Publications (21)34.82 Total impact
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Article: Parallel evolution in eight-barbel loaches of the genus Lefua (Balitoridae, Cypriniformes) revealed by mitochondrial and nuclear DNA phylogenies.
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ABSTRACT: The evolutionary history of eight-barbel loaches of the genus Lefua contains important phylogenetic information that will aid in resolution of the faunal formations and evolutionary histories of Japanese and East Asian freshwater fishes. Our sequencing of the mitochondrial D-loop region in a large number of samples allowed construction of the most comprehensive phylogeny of these loaches to date; we demonstrated monophyly of five Lefua species and identified populations of Lufua. sp. and Lefua echigonia. Loaches inhabiting the Tokai region in Japan were morphologically and ecologically indistinguishable from Lefua sp. However, they were included in the L. echigonia lineage. We determined a novel phylogeny by sequencing the nuclear ribosomal S7 subunit and showed that nuclear DNA phylogeny essentially matched the mitochondrial DNA phylogeny. Loaches from the Tokai region were part of the L. echigonia lineage, indicating parallel evolution between Tokai loaches and Lefua sp. in western Japan. We presented the most robust phylogeny to date using concatenated mitochondrial and nuclear sequences. The wealth of molecular information allowed us to speculate on evolutionary processes in the genus Lefua.Molecular Phylogenetics and Evolution 05/2011; 60(3):416-27. · 3.61 Impact Factor -
Chapter: Japan: Vents and Seeps in Close Proximity
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ABSTRACT: Since the discovery of dense animal communities associated with deep-sea hydrothermal venting (Lonsdale 1997), biological knowledge of those animals has accumulated (Van Dover 2000). Some unique animals associated with vent fields were found to depend on chemosynthetic primary production (Corliss et al. 1979). Subsequently, similar chemosynthetic animal assemblages were also discovered associated with deep-sea methane-seep areas, whale falls, and sunken wood (Paull et al. 1984; Smith et al. 1989). To understand the pathways of adaptation to these environments, species shared between different habitats are of particular interest (Distel et al. 2000; Lorion et al. 2008). On a global scale, the number of species shared between vents and seeps is less than 10% of the total recorded vent or seep species (e.g. Tunnicliffe et al. 1998, 2003; Sibuet and Olu 1998). In the vent and seep communities around Japan, however, this figure exceeds 20% (based on a faunal list provided by Fujikura et al. 2008), although the identification of species is still in progress. This relatively high abundance of both vent- and seep-inhabiting species suggests close relationships between vent and seep communities around Japan. A high similarity between megafaunal communities at vents and seeps around Japan was already noted by Fujikura et al. (1995); however, that study was based on species abundances investigated at only a single vent and two methane-seep communities. To date, at least 55 vent and seep communities have been discovered around Japan (Fujikura et al. 2008), and further analyses are required to elucidate the nature of this similarity.09/2010: pages 379-401; -
Article: Population divergence of Biwia zezera (Cyprinidae: Gobioninae) and the discovery of a cryptic species, based on mitochondrial and nuclear DNA sequence analyses.
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ABSTRACT: Mitochondrial and nuclear DNA analyses were used to examine the native distribution range and population structure of Biwia zezera (Cyprinidae: Gobioninae) based on specimens from the species' presumed distribution range. We found two greatly differentiated groups, with 8.6% uncorrected sequence differences in the mtDNA cytochrome b gene; one group was distributed exclusively in the Yodo River system (excluding Lake Biwa and rivers flowing into the lake). This differentiation was supported by results from three nuclear DNA loci, and it was concluded that the Yodo population is an undescribed cryptic species. Based on mtDNA haplotype distribution and endemicity, B. zezera was determined to be indigenous to the Ise Bay area (Nobi Plain), Lake Biwa basin (excluding the Yodo River outlet and its tributaries), the Sanyo region, and northern Kyushu. The population in the Ise Bay area was the most differentiated from the others, while that in Kyushu was the second-most differentiated. It was confirmed that an endemic population closely related to the Lake Biwa population is naturally distributed in the Sanyo region.ZOOLOGICAL SCIENCE 08/2010; 27(8):647-55. · 0.95 Impact Factor -
Article: Extracellular and mixotrophic symbiosis in the whale-fall mussel Adipicola pacifica: a trend in evolution from extra- to intracellular symbiosis.
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ABSTRACT: Deep-sea mussels harboring chemoautotrophic symbionts from hydrothermal vents and seeps are assumed to have evolved from shallow-water asymbiotic relatives by way of biogenic reducing environments such as sunken wood and whale falls. Such symbiotic associations have been well characterized in mussels collected from vents, seeps and sunken wood but in only a few from whale falls. Here we report symbioses in the gill tissues of two mussels, Adipicola crypta and Adipicola pacifica, collected from whale-falls on the continental shelf in the northwestern Pacific. The molecular, morphological and stable isotopic characteristics of bacterial symbionts were analyzed. A single phylotype of thioautotrophic bacteria was found in A. crypta gill tissue and two distinct phylotypes of bacteria (referred to as Symbiont A and Symbiont C) in A. pacifica. Symbiont A and the A. crypta symbiont were affiliated with thioautotrophic symbionts of bathymodiolin mussels from deep-sea reducing environments, while Symbiont C was closely related to free-living heterotrophic bacteria. The symbionts in A. crypta were intracellular within epithelial cells of the apical region of the gills and were extracellular in A. pacifica. No spatial partitioning was observed between the two phylotypes in A. pacifica in fluorescence in situ hybridization experiments. Stable isotopic analyses of carbon and sulfur indicated the chemoautotrophic nature of A. crypta and mixotrophic nature of A. pacifica. Molecular phylogenetic analyses of the host mussels showed that A. crypta constituted a monophyletic clade with other intracellular symbiotic (endosymbiotic) mussels and that A. pacifica was the sister group of all endosymbiotic mussels. These results strongly suggest that the symbiosis in A. pacifica is at an earlier stage in evolution than other endosymbiotic mussels. Whale falls and other modern biogenic reducing environments may act as refugia for primal chemoautotrophic symbioses between eukaryotes and prokaryotes since the extinction of ancient large marine vertebrates.PLoS ONE 01/2010; 5(7):e11808. · 4.09 Impact Factor -
Article: Evolutionary process of deep-sea bathymodiolus mussels.
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ABSTRACT: Since the discovery of deep-sea chemosynthesis-based communities, much work has been done to clarify their organismal and environmental aspects. However, major topics remain to be resolved, including when and how organisms invade and adapt to deep-sea environments; whether strategies for invasion and adaptation are shared by different taxa or unique to each taxon; how organisms extend their distribution and diversity; and how they become isolated to speciate in continuous waters. Deep-sea mussels are one of the dominant organisms in chemosynthesis-based communities, thus investigations of their origin and evolution contribute to resolving questions about life in those communities. We investigated worldwide phylogenetic relationships of deep-sea Bathymodiolus mussels and their mytilid relatives by analyzing nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4) genes. Phylogenetic analysis of the concatenated sequence data showed that mussels of the subfamily Bathymodiolinae from vents and seeps were divided into four groups, and that mussels of the subfamily Modiolinae from sunken wood and whale carcasses assumed the outgroup position and shallow-water modioline mussels were positioned more distantly to the bathymodioline mussels. We provisionally hypothesized the evolutionary history of Bathymodilolus mussels by estimating evolutionary time under a relaxed molecular clock model. Diversification of bathymodioline mussels was initiated in the early Miocene, and subsequently diversification of the groups occurred in the early to middle Miocene. The phylogenetic relationships support the "Evolutionary stepping stone hypothesis," in which mytilid ancestors exploited sunken wood and whale carcasses in their progressive adaptation to deep-sea environments. This hypothesis is also supported by the evolutionary transition of symbiosis in that nutritional adaptation to the deep sea proceeded from extracellular to intracellular symbiotic states in whale carcasses. The estimated evolutionary time suggests that the mytilid ancestors were able to exploit whales during adaptation to the deep sea.PLoS ONE 01/2010; 5(4):e10363. · 4.09 Impact Factor -
Article: Interaction of Chicken Liver Tropomyosin with Glutamate Dehydrogenase
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ABSTRACT: Tropomyosin (TM) is one of the actin-regulatory proteins and stabilizes the filamentous structure of F-actin. Although it has been suggested that multiple TM isoforms play important roles in nonmuscle cells and several TM-binding proteins have been identified and characterized, the functional properties of nonmuscle TM isoforms are not well understood. In order to investigate the roles of TM in nonmuscle cells, we searched for novel nonmuscle TM-binding proteins from the chicken liver total acetone powder extract by TM-affinity column chromatography. As a consequence, a protein of 57 kDa was mainly eluted from the column and its partial amino acid sequence of the protease-digested fragment was determined. Homology search using SWISS-PLOT showed that the 57 kDa protein was nearly identical to chicken glutamate dehydrogenase (GDH: EC 1.4.1.3). Purified GDH had the ability to bind to the TM-affinity column, indicating that GDH associated directly with liver TM. The binding of GDH to TM was abolished in the presence of 0.1 mM ATP, that is known to decrease the rate of the GDH enzymatic activity at pH 7.5. Thus, we have demonstrated the interaction between nonmuscle TM and GDH for the first time.ZOOLOGICAL SCIENCE 02/2009; · 0.95 Impact Factor -
Article: Developmental Stage-Dependent Expression of Troponin T Isoforms in Chicken Embryonic Breast Muscles Grafted on Chorio-Allantoic Membrane
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ABSTRACT: To examine whether the expression pattern of muscle-specific protein in embryonic muscle tissues at the different developmental stages depends on the types of myogenic cells, chicken breast muscle (pectoralis major) tissues of 10-day, 14-day, and 18-day old embryos (E10, E14, and E18, respectively) were grafted on chorio-allantoic membrane (CAM) of 9-day-old chicken embryos and cultured for 12 days at the longest, since the chorio-allantoic grafting is useful in pursuing muscle-cell lineage during muscle differentiation. The muscle fiber formation and expression of troponin T (TnT) isoforms in grafts were investigated by histological and immunohistochemical methods with anti-fast-muscle-type and anti-slow-muscle-type TnT (rabbit sera). In grafts of E10 breast muscle, most muscle fibers continued to develop without degeneration and TnT isoform expression of the fibers changed from the concomitant expression of fast-muscle-type (Ftype) and slow-muscle-type (S-type) to the expression of F-type only. In grafts of E14 and E18 breast muscles, the muscle fibers first degenerated with pyknotic nuclei and hyaline cytoplasm, and then new muscle fibers expressing F-type TnT isoforms were formed by the fusion of basophilic cells. The new muscle fibers in grafts of E14 muscles were different from those of E18 ones in that the former also expressed S-type TnT isoforms. In this paper, developmental stage-dependent TnT isoform expression of the embryonic breast muscles grafted on CAM is discussed in connection with cell-type difference of grafted muscle cells.ZOOLOGICAL SCIENCE 01/2009; · 0.95 Impact Factor -
Article: Incongruence between mtDNA phylogeny and morphologial and ecological characters in loaches of the genus Lefua (Balitoridae, Cypriniformes).
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ABSTRACT: To elucidate the phylogenetic position of Lefua loaches from Aichi and Shizuoka Prefectures of Honshu Island, Japan, we determined their nucleotide sequences for the mitochondrial D-loop region and compared these to sequences from four other Lefua species: L. costata, L. nikkonis, L. echigonia, and L. sp. Loaches identified as L. sp. on the basis of morphology comprised a clade (the L. sp. Tokai population) that grouped together with L. echigonia; hence, the processes involved in evolution within the genus Lefua were unclear. We performed randomly amplified polymorphic DNA (RAPD) analyses to obtain genetic information on nuclear DNA. The RAPD patterns of the L. sp. Tokai population differed from those of the local L. echigonia and L. sp. populations. The L. sp. Tokai population was similar to L. echigonia with regard to mitochondrial DNA but differed from L. echigonia and L. sp. with respect to nuclear DNA; this indicated that the evolutionary background of the L. sp. Tokai population was unique. We suggest that introgression of mitochondria occurred from L. echigonia to the L. sp. Tokai population, and speculate on the process of evolution of the latter population of Lefua. As with six L. echigonia populations and two L. sp. populations, we regard the L. sp. Tokai population as an evolutionary significant unit (ESU) that qualifies for protection as an endangered loach.ZOOLOGICAL SCIENCE 08/2007; 24(7):666-75. · 0.95 Impact Factor -
Article: Evolutionary relationships of deep-sea mussels inferred by mitochondrial DNA sequences
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ABSTRACT: In order to elucidate the evolutionary process of deep-sea Bathymodiolus mussels, we investigated the phylogenetic relationships of 16 species worldwide by analyzing nucleotide sequences of the mitochondrial COI and ND4 genes. Deep-sea mussels were clustered into three groups by basal trichotomous divergence. The first was composed of four species found in Japanese waters and one species from the Gulf of Mexico, which contain methanotrophic endosymbiotic bacteria. The second included nine species distributed in the West and East Pacific, Indian, and Atlantic Oceans. Members of the second group were trichotomously divided into the Indo-West Pacific, Atlantic, and East Pacific subclusters. The Indo-West Pacific subcluster was composed of three very closely related species with mutual genetic distances at the intraspecific level (av. 0.019 in COI and 0.009 in ND4 relative to av. 0.156 in COI and 0.265 in ND4 among Bathymodiolus species other than Cluster A species), suggesting some gene flow among these species. The third consisted of two West Pacific species. Species in the second and third groups contain mainly thioautotrophic endosymbionts, including some species harboring both methanotrophs and thioautotrophs.Marine Biology 07/2006; 149(5):1111-1122. · 2.28 Impact Factor -
Article: Tissue specificity of arthropod tropomyosin
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ABSTRACT: In order to elucidate whether tropomyosin isoforms have different tissue-specific functions, we examined tissue specificity of tropomyosin by two-dimensional gel electrophoresis and immunoreplica tests using three arthropod species. These arthropods showed molecular heterogeneity and tissue specificity of tropomyosin in muscle and nonmuscle tissues. The beetle (Insecta) and centipede (Chilopoda) had three different isoforms. The scorpion (Arachnida) had six isoforms, two of which were nonmuscle-specific. In addition to these isoforms, all the species contained nonmusclespecific isoforms of high electrophoretic mobilities and another isoform with a high electrophoretic mobility was found in the beetle heart and intestine. We summarized the results including the data from our previous studies on the horseshoe crab (Merostomata) and five crustaceans (Crustacea) and found that most isoforms were not shared by every tissue but detected in some particular tissues. In that sense, they were tissue specific, but each of them was not restricted to a single tissue. However, crustacean cardiac isoforms were contained exclusively in the hearts, and some of the nonmuscle isoforms were not found in other tissues; thus they were tissue specific in the strict sense. Considering our results and those on vertebrate tropomyosin together, we suggest that the existence of different isoforms alone does not imply straightforwardly different functions among the isoforms and that only strictly tissue-specific isoforms can be assumed to have functions peculiar to their tissues. © 1993 wiley-Liss, Inc.Journal of Experimental Zoology 06/2005; 267(5):501 - 509. -
Article: Tissue specificity of crustacean tropomyosin
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ABSTRACT: The tropomyosin isoform distribution in muscle and nonmuscle tissues of crustaceans was investigated by two-dimensional gel electrophoresis and immunoreplica tests. All five crustacean species examined in this study showed extensive molecular heterogeneity and tissue specificity of tropomyosin. The results were different from those previously reported with the horseshoe crab, that is, horseshoe crab tropomyosin was heterogeneous but not tissue-specific. In this respect, therefore, the distribution of crustacean tropomyosin isoforms is more similar to that of vertebrate tropomyosin isoforms rather than that of horseshoe crab tropomyosin isoforms. Furthermore, crustacean nonmuscle tissues contained tropomyosin isoforms of high electrophoretic mobilities, which were possible counterparts of so-called vertebrate nonmuscle isoforms of low molecular weights. However, it is rather difficult to expect that each tropomyosin isoform has a tissue-specific function, since the patterns of isoform composition were not consistent among the examined crustaceans except for those of cardiac isoforms, which were unique to the hearts in all the examined crustaceans and correlated with the expression of presumed actin of compound peptides, which specifically appeared in the hearts. Therefore, the cardiac isoforms of crustacean tropomyosin are suggested to play tissue-specific regulatory roles. © 1992 Wiley-Liss, Inc.Journal of Experimental Zoology 05/2005; 263(3):235 - 244. -
Article: Phylogeography of loaches of the genus lefua (balitoridae, cypriniformes) inferred from mitochondrial DNA sequences.
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ABSTRACT: In order to elucidate phylogenetic relationships and intraspecific variations and to infer the evolutionary process of loaches of the genus Lefua, we analyzed nucleotide sequences of the mitochondrial D-loop region of 100 specimens obtained from 97 localities in Japan and Korea. The genus Lefua includes three described species, L. nikkonis, L. echigonia, and L. costata and an undescribed species, Lefua sp. Our results showed that each species of Lefua formed a monophyletic group, indicating clearly that Lefua species can be genetically distinguished from one another. Lefua nikkonis was the most closely related to L. costata, while L. sp. was the most closely related to L. echigonia. Specimens of L. sp. were grouped into two intraspecific populations and specimens of L. echigonia were grouped into six populations. These populations were well separated geographically from one another by mountain ranges and highlands. We estimated the evolutionary time for splitting of the species and intraspecific populations, and speculated on the evolutionary process of the genus Lefua. Species of Lefua are severely threatened. Fundamental genetic information is indispensable for conservation. We presented genetic background in order to protect these threatened loaches.ZOOLOGICAL SCIENCE 03/2005; 22(2):157-68. · 0.95 Impact Factor -
Article: Genomic structure of the chicken slow skeletal muscle troponin T gene.
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ABSTRACT: Troponin T (TnT) is a key protein for Ca(2+)-sensitive molecular switching of muscle contraction. In vertebrates, three TnT genes have been identified, which produce isoforms characteristic of cardiac, fast skeletal, and slow skeletal muscles through alternative splicing in a tissue-specific and developmentally regulated manner. The diversification of myofibers into forms with specific metabolic and contractile characteristics is thought to be closely associated with the differential expression of these TnT isoforms. Herein, we determined the nucleotide sequence of the chicken slow skeletal muscle TnT gene and its upstream region. The gene was simpler in structure than the two other chicken genes. The transcription initiation site was positioned 183 bp upstream of the 3' end of exon 1. Alternative splicing of exon 5 using an internal acceptor site generated two distinct slow skeletal muscle troponin T (sTnT) transcripts. We identified possible regulatory elements, M-CAT-like, CACC-box, and E-box (E-box1 to E-box3) motifs in the upstream region and an E-box motif (E-box4) in exon 1.Gene 10/2004; 338(2):243-56. · 2.34 Impact Factor -
Article: Change from a hard to soft diet alters the expression of insulin-like growth factors, their receptors, and binding proteins in association with atrophy in adult mouse masseter muscle.
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ABSTRACT: To study the role of insulin-like growth factors (IGFs) in the atrophy of mouse masseter muscle in response to a change from a hard to a soft diet, we analyzed the amounts of mRNA and the immunolocalization for IGF-I, IGF-II, their receptors (IGFRs), and binding proteins (IGFBPs). Sixteen male ICR mice were fed a hard diet after weaning; they were divided into two groups at 6 months of age and fed a hard or a soft diet for 1 week. The soft diet treatment decreased masseter weight by 19% ( P<0.01) and the minimal diameter of masseter myofibers by 19% ( P<0.01), verifying that a soft diet led to atrophy of mouse masseter muscle. The soft diet treatment induced a 30% reduction in the amount of IGF-I mRNA ( P<0.05) in preparations of whole masseter tissues. Immunohistochemical findings suggested that a reduction in the expression of IGF-I protein took place in the neural tissues, not in the masseter myofibers. The soft diet treatment induced a 56% decrease in IGF-II mRNA ( P<0.05), a 21% increase in IGFR2 mRNA ( P<0.01), and a 38% decrease in IGFBP5 mRNA ( P<0.01). Immunohistochemical results suggested that these changes at the protein level occurred in the masseter myofibers. No significant or marked difference in the mRNA amount or immunostaining pattern for IGFR1, IGFBP3, IGFBP4, or IGFBP6 was found between the soft and hard diet groups. No IGFBP1 or IGFBP2 mRNA was detected. Thus, IGF-I, IGF-II, IGFR2, and IGFBP5 seem to play a role in the atrophy of mouse masseter muscle in response to the change from a hard to a soft diet in an autocrine and/or paracrine manner.Cell and Tissue Research 01/2004; 315(1):97-105. · 3.11 Impact Factor -
Article: Phylogenetic relationships and intraspecific variations of loaches of the genus Lefua (Balitoridae, Cypriniformes).
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ABSTRACT: Three nominal species are known in East Asian balitorid loaches of the genus Lefua, i.e. L. echigonia, L. nikkonis, and L. costata. Lefua echigonia, with large morphological variations was recently separated into two groups, L. echigonia including the holotype and L. sp., based on morphological and ecological traits. We performed protein and DNA analyses to elucidate phylogenetic relationships among loaches of the genus Lefua and to settle the taxonomic status of L. sp. We also investigated intraspecific variations in L. echigonia s. str. to shed light on the process of formation of freshwater fish fauna in Japan. Protein analyses using two-dimensional gel electrophoresis showed that genetic distances between L. sp. and L. echigonia s. str. and between L. sp. and L. nikkonis were as large as that between L. echigonia s. str. and L. nikkonis. DNA analyses of the mitochondrial D-loop region showed that L. sp. and L. echigonia s. str. were monophyletic, respectively, while neither L. nikkonis nor L. costata was monophyletic and these species formed together a clade. The results supported the specific status of L. sp. and proposed reevaluation of the taxonomic status of L. nikkonis and L. costata. DNA analyses also showed that L. sp. was more closely related to L. echigonia s. str. than to the L. nikkonis-L. costata complex, and four local populations were distinguished in L. echigonia s. str. Distribution patterns of the four local populations of L. echigonia s. str. in Japan were approximately congruent with those of the medaka, Oryzias latipes, suggesting that differentiation in the two distantly related fishes have a common historical background.ZOOLOGICAL SCIENCE 05/2003; 20(4):501-14. · 0.95 Impact Factor -
Article: Expression of multiple troponin T isoforms in chicken breast muscle regeneration induced by sub-serous implantation.
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ABSTRACT: Chicken fast-muscle type (F-type) troponin T (TnT) isoforms are classified into two types, leg-muscle type (L-type) and breast-muscle type (B-type), which are generated by exclusion and inclusion of exon x series-derived sequences in mRNAs, respectively. The B-type isoforms are further classified into neonatal breast-muscle (BN), young chicken breast-muscle (BC), and adult chicken breast-muscle (BA) subtypes. It is known that the multiple F-type TnT isoforms are transiently expressed in the breast muscle tissue during normal development. To examine whether the transition of the isoforms was fixed in muscle cell lineage, breast muscle pieces (pectoralis major) of 1-day old chicks were cultured under gizzard serous membrane of the same chicks for 60 days at the longest. TnT isoform expression of the implants was monitored by immunoblotting and immunostaining using anti-F-type TnT against both L-type and B-type isoforms, anti-exon x3 against only B-type isoforms, and anti-S-type TnT against slow-muscle-type (S-type) isoforms. Muscle fibers in the implant degenerated first, and then new myotubes expressing L-type isoforms were formed by the fusion of myoblasts from surviving satellite cells. When the maturation of the myotubes into myofibers proceeded, BN-, BC-, and BA-subtype isoforms were expressed in the order of developmental stage specific-manner, indicating that the order of appearance of these isoforms was fixed in muscle cell lineage. In immunostaining of the implants recovered on the 60th day after implantation, at least three kinds of the regenerated myofibers were observed, expressing mainly B-type, both B-type and L-type, and only L-type isoforms. The immunohistochemical results suggested that the regulation of alternative splicing of F-type TnT pre-mRNAs was different among individual myofibers, and that the regulation was programmed in myogenic cells, probably satellite cells, which were the primary source of the fibers.Differentiation 06/2002; 70(2-3):92-100. · 2.81 Impact Factor -
Article: Biochemical and immunohistochemical studies on tropomyosin and glutamate dehydrogenase in the chicken liver.
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ABSTRACT: Recently, we have reported a novel tropomyosin (TM) -binding protein, glutamate dehydrogenase (GDH) and demonstrated by affinity column chromatography that chicken liver TM interacts with GDH in an ATP-dependent manner. To elucidate the physiological roles of the interaction between TM and GDH, we performed co-sedimentation assays of TM and GDH with F-actin, because it is known that TM exerts its physiological functions by associating with actin filaments. The results showed that TM and GDH co-pelleted with F-actin. GDH alone also co-precipitated with F-actin, but the amount of GDH sedimenting with F-actin was increased in the presence of chicken liver TM, suggesting that GDH is involved in the regulation of the actin cytoskeleton. We also prepared crude GDH from the nuclear and mitochondrial fractions obtained by subcellular fractionation of the chicken liver cells. Semi-nondenaturing 2D-PAGE revealed that partially purified GDH from the nuclear fraction was associated with TM, but not GDH from the mitochondrial fraction, suggesting preferential binding of TM to GDH. We determined the nucleotide sequence of chicken GDH cDNA and showed that the GDH transcript was widely expressed in the chicken organs. We examined the localization of TM and GDH by immunohistochemistry and revealed that they were distributed in the cytoplasm of the adult chicken liver. From these results, we propose two hypotheses on the physiological roles of the interaction between TM and GDH in nonmuscle cells.ZOOLOGICAL SCIENCE 04/2002; 19(3):275-86. · 0.95 Impact Factor -
Article: Developmental changes of cardiac and slow skeletal muscle troponin T expression in chicken cardiac and skeletal muscles.
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ABSTRACT: Numerous troponin T (TnT) isoforms are produced by alternative splicing from three genes characteristic of cardiac, fast skeletal, and slow skeletal muscles. Apart from the developmental transition of fast skeletal muscle TnT isoforms, switching of TnT expression during muscle development is poorly understood. In this study, we investigated precisely and comprehensively developmental changes in chicken cardiac and slow skeletal muscle TnT isoforms by two-dimensional gel electrophoresis and immunoblotting with specific antisera. Four major isoforms composed of two each of higher and lower molecular weights were found in cardiac TnT (cTnT). Expression of cTnT changed from high- to low-molecular-weight isoforms during cardiac muscle development. On the other hand, such a transition was not found and only high-molecular-weight isoforms were expressed in the early stages of chicken skeletal muscle development. Two major and three minor isoforms of slow skeletal muscle TnT (sTnT), three of which were newly found in this study, were expressed in chicken skeletal muscles. The major sTnT isoforms were commonly detected throughout development in slow and mixed skeletal muscles, and at developmental stages until hatching-out in fast skeletal muscles. The expression of minor sTnT isoforms varied from muscle to muscle and during development.ZOOLOGICAL SCIENCE 03/2002; 19(2):215-23. · 0.95 Impact Factor -
Article: Differential expression of mutually exclusive exons of the fast skeletal muscle troponin T gene in the chicken wing and leg muscles.
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ABSTRACT: To determine the physiological significance of developmentally regulated and muscle tissue-specific expression of troponin T (TnT) isoforms and also to elucidate mechanisms of alternative splicing, we investigated splicing patterns of fast skeletal muscle TnT by sequencing cDNAs obtained from the chicken wing and leg muscles. The chicken fast skeletal muscle TnT gene has 27 exons, and produces potentially 2(15) transcripts if alternative exons are randomly spliced. For the fourteen alternative exons in the 5'-region of the gene, we found 7 and 12 splice variants in the wing biceps brachii and leg gastrocnemius, respectively. Out of 19, 12 variants were newly found in this study. Twenty two different splice variants were reported by the previous studies, but this number has now increased to 34 in the chicken TnT gene, suggesting that alternative splicing is not random, but strictly regulated. We also investigated splicing patterns of mutually exclusive exons 16 and 17 in the 3'-region of the gene. Approximately equal amounts of cDNAs containing exons 16 and 17 were detected in proximal regions of adult biceps brachii and gastrocnemius, respectively, whereas cDNA with exon 17 dominated in distal regions. Only cDNA containing exon 17 was found in both proximal and distal regions of 5-day-old gastrocnemius. The inclusion of exon 16 into cDNAs was detected in the proximal region of 15-day-old gastrocnemius and increased during development.Journal of Muscle Research and Cell Motility 02/2002; 23(3):235-43. · 1.98 Impact Factor -
Article: The gradual expression of troponin T isoforms in chicken wing muscles
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ABSTRACT: Troponin T (TnT) is one of the muscle regulatory proteins and is thought to be related to unique contractile properties in diverse muscles and also to myogenesis. The expression of TnT isoforms in the chicken wing muscles was investigated by two-dimensional gel electrophoresis and immunoblotting with an antiserum against fast skeletal muscle TnT. The upper arm muscles, M. biceps brachii and M. triceps brachii, showed striking differential expression of high molecular weight B type and low molecular weight L type TnT isoforms in the proximal, middle and distal portions of each muscle. The ratio of the total quantity of B type TnT isoforms to that of L type TnT isoforms decreased gradually along the proximo-distal axis of the wing. The upper arm muscles, M. deltoideus and M. tensor patagii longus, and most of the lower arm muscles examined in this study did not show such differential expression. The lower arm muscles, M. flexor carpi ulnaris and M. extensor carpi radialis longus, showed some gradual expression of TnT isoforms, but the B/L ratio in the former slightly increased along the proximo-distal axis. The gradual expression in M. biceps brachii was not found in the 1-day-old chick, but was established by 30 days post-hatching. The biological significance of differential expression of TnT isoforms in different muscles and even in single muscles was speculated upon with respect to muscle contractile regulation and myogenesis.Journal of Muscle Research and Cell Motility 11/2001; 22(8):693-701. · 1.98 Impact Factor
Top co-authors
Top Journals
Institutions
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2006–2011
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Yamanashi University
- Faculty of Education and Human Sciences
Kōfu-shi, Yamanashi-ken, Japan
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2010
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Kyoto University
- Department of Zoology
Kyoto, Kyoto-fu, Japan -
Japan Agency for Marine-Earth Science Technology
Yokosuka, Kanagawa-ken, Japan
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2009
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Keio University
Tokyo, Tokyo-to, Japan
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2002–2009
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University of Tsukuba
- Institute of Biological Sciences
Tsukuba, Ibaraki-ken, Japan
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1998
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Fisheries Research Agency
Yokohama-shi, Kanagawa-ken, Japan
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