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ABSTRACT: A new chloroplastic Cu/Zn-superoxide dismutase (SOD) isoenzyme was identified in Arabidopsis thaliana ecotype Cvi. Genetic analyses indicated that the new isoenzyme was encoded by a Cvi-specific allele of Csd2 that was named Csd2-2. Paraquat treatments of A. thaliana ecotypes Ler and Cvi resulted in higher levels of chloroplastic Cu/Zn-SOD activity in Cvi, suggesting that the Cvi isoenzyme has a higher stability and/or turnover rate than the Ler variant under photo-oxidative conditions. In addition, Cvi showed a higher tolerance to paraquat treatments. Hybrid plant populations expressing Csd2-2 also exhibited an increased tolerance, suggesting that the Cvi isoenzyme is one of the factors that contribute to a better fitness in photo-oxidative stress conditions.
Journal of Experimental Botany 08/2001; 52(360):1417-25. · 5.36 Impact Factor
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ABSTRACT: The structural requirements for dimerization of RCI14A and RCI14B, two 14-3-3 isoforms from Arabidopsis thaliana, have been analyzed by testing truncated forms of RCI14A for dimerization with full-length RCI14A and RCI14B. The results show that only the fourth helix of the truncated partner is essential for dimerization, which represents a difference from what is known for animal isoforms. On the other hand, the effect of calcium has been tested in RCI14A homodimerization. Millimolar concentrations of calcium exert a negative, dose-dependent effect that involves the C-terminal domain of RCI14A and might modulate interactions with other cellular components or among Arabidopsis 14-3-3 isoforms.
FEBS Letters 01/2000; 462(3):377-82. · 3.54 Impact Factor
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ABSTRACT: Two genes (SCR1 and SCR2) encoding natural cycloheximide resistance in the budding yeast Schwanniomyces occidentalis have been cloned by expression in Saccharomyces cerevisiae. Both genes determine resistance to the inhibitory action of cycloheximide on the ribosome, SCR1 and SCR2 are present as single copies in Schwanniomyces occidentalis, where they map on chromosomes II and V, respectively. The nucleotide sequence of SCR2 contains an open reading frame of 321 nucleotides which is interrupted by an intron of 452 nucleotides. It encodes a polypeptide of 106 amino acids of molecular mass 12.25 kDa and pI 11.19. The deduced amino acid sequence shows a high degree of similarity to the L41 protein of the 60S ribosomal subunit from several eukaryotic organisms. The intron and the 5' non-coding region of SCR2 possess conserved elements which are typical of yeast ribosomal protein genes. A single amino acid change determines the resistance or sensitive phenotype to cycloheximide of the 80S ribosome since replacement of Gln56 in L41 from Schwanniomyces with Pro, by site-directed mutagenesis, confers cycloheximide sensitivity. SCR2 may serve as a practical yeast cloning marker if integrated in a multicopy plasmid.
European Journal of Biochemistry 05/1993; 213(2):849-57. · 3.58 Impact Factor
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ABSTRACT: The SGA and STA2 genes that, respectively, encode the intra- and extracellular glucoamylases of Saccharomyces cerevisiae are coregulated negatively, at the level of transcription, by the STA10 gene. This finding was re-examined by determining the effects of STA10 on the expression of gene constructs containing different fragments from the SGA and STA2 promoter regions fused to the lacZ gene. Repression was observed only for promoter fragments carrying the sequence GTACAAG indicating that this element is responsible for the coregulation of SGA and STA2 by STA10.
FEMS Microbiology Letters 05/1992; 71(1):57-62. · 2.04 Impact Factor
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ABSTRACT: In CYH2/cyh2 heterozygous diploids of the yeast Saccharomyces cerevisiae resistance is dominant over sensitivity at low (0.5-5 micrograms/ml) cycloheximide (cyh) concentrations. The cyh-resistant haploid strain MMY1 confers relatively high (10 micrograms/ml) cyh-resistance to heterozygous diploids constructed by mating this strain with cyh-sensitive haploid strains. We present here a genetic and biochemical study of strain MMY1. Analysis of tetrads obtained from a MMY1 heterozygous diploid showed that two unlinked nuclear mutations, determining high- and low-cycloheximide resistance, were present in MMY1. From a genomic library of this strain, constructed in vector YCp50, two plasmids (pRC1 and pRC13) have been isolated which, respectively, confer high- and low-resistance phenotypes to cyh-sensitive S. cerevisiae strains. The restriction maps of pRC1 and pRC13 are totally unrelated. This finding suggests that the genes harboring the two mutations encoding cyh-resistance from MMY1 were cloned in plasmids pRC1 and pRC13, respectively. Pulse field gel electrophoresis showed that the DNA insert of pRC1 maps at either chromosome VII or XV, whereas that from pRC13 maps at chromosome XI. This latter gene appears to define a previously unreported locus and has been named cyh5. By restriction and nucleotide sequencing analysis, the cyh gene present in pRC1 has been shown to correspond to cyh2, which maps at chromosome VII. These results suggest that the dominant cyh-resistance phenotype conferred by MMY1 in heterozygous diploids is promoted by the presence of both cyh2 and cyh5.(ABSTRACT TRUNCATED AT 250 WORDS)
Current Genetics 06/1991; 19(5):353-8. · 2.56 Impact Factor
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ABSTRACT: A new gene (SW A2) encoding a secretory alpha-amylase activity from Schwanniomyces occidentalis has been cloned from this yeast and then expressed in Saccharomyces cerevisiae. Both Sw, occidentalis and a transformant of S. cerevisiae incorporating SW A2 contain a transcript of 2.1 kb which hybridizes to DNa carrying the SW A2 gene. This indicates that the transcript is a product of the SW A2 gene. Transcription of the SW A2 gene seems to be regulated in both Sw. occidentalis and S. cerevisiae. Furthermore, the secretion of alpha-amylase activity is drastically repressed by glucose in both Sw. occidentalis and a transformant of S. cerevisiae containing SW A2.
FEBS Letters 03/1991; 279(1):41-4. · 3.54 Impact Factor
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ABSTRACT: A gene (SWA1) encoding an alpha-amylase activity from Schwanniomyces castellii has been cloned and expressed, via yeast cloning vector YEp13, in Saccharomyces cerevisiae. By using a riboprobe which is internal to the SWA1 gene, a 1.55 kb transcript was detected in the poly(A)+ RNA from both Sw. castellii and a S. cerevisiae clone harboring the SWA1 gene. This transcript should, therefore, correspond to the SWA1 gene. In addition, the DNA strand determining the alpha-amylase activity has been defined. Transcription of the SWA1 gene appears to be highly regulated in Sw. castellii, whereas it is constitutive in the S. cerevisiae harboring this gene.
FEBS Letters 10/1989; 255(2):455-9. · 3.54 Impact Factor
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ABSTRACT: A new gene (SW A2) encoding a secretory α-amylase activity from Schwanniomyces occidentalis has been cloned from this year and then expressed in Saccharomyces cerevisiae. Both Sw. occidentalis and a transformant of S. cerevisiae incorporating SW A2 contain a transcript of 2.1 kb which hybridizes to DNA carrying the SW A2 gene. This indicates that the transcript is a product of the SW A2 gene. Transcription of the SW A2 gene seems to be regulated in both Sw. occidentalis and S. cerevisiae. Furthermore, the secretion of α-amylase activity is drastically expressed by glucose in both Sw. occidentalis and a transformant of S. cerevisiae containing SW A2.
FEBS Letters.
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ABSTRACT: A 2.1-kb DNA fragment containing the SWA2 gene determining an alpha-amylase from Schwanniomyces occidentalis has been sequenced. It contains an open reading frame of 1521 bp which has the potential to encode a 507 amino-acid protein of M(r) 55966. Its deduced amino-acid sequence shows significant similarities to the sequence of other studied alpha-amylases. These similarities identify a consensus sequence, F(LIV)(ED)NHD, which is shared in addition by most maltases, invertases and glucoamylases.
Current Genetics 24(1-2):75-83. · 2.56 Impact Factor
