Jong-A Park

Yonsei University, Seoul, Seoul, South Korea

Are you Jong-A Park?

Claim your profile

Publications (9)28.66 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study addresses the physiological functions of the Ran-binding protein homolog NbRanBP1 in Nicotiana benthamiana. Virus-induced gene silencing (VIGS) of NbRanBP1 caused stunted growth, leaf yellowing, and abnormal leaf morphology. The NbRanBP1 gene was constitutively expressed in diverse tissues and an NbRanBP1:GFP fusion protein was primarily localized to the nuclear rim and the cytosol. BiFC analysis revealed in vivo interaction between NbRanBP1 and NbRan1 in the nuclear envelope and the cytosol. Depletion of NbRanBP1 or NbRan1 reduced nuclear accumulation of a NbBTF3:GFP marker protein. In the later stages of development, NbRanBP1 VIGS plants showed stress responses such as reduced mitochondrial membrane potential, excessive production of reactive oxygen species, and induction of defense-related genes. The molecular role of RanBP1 in plants is discussed in comparison with RanBP1 function in yeast and mammals.
    Molecules and Cells 06/2008; 26(3):270-7. · 2.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BTF3 (betaNAC) was originally isolated as a general transcription factor required for RNA polymerase II-dependent transcription, and later found to be a beta-subunit of nascent-polypeptide-associated complex that has been implicated in regulating protein localization during translation. In this study, virus-induced gene silencing of NbBTF3 encoding a Nicotiana benthamiana homolog of human BTF3 caused leaf yellowing and abnormal leaf morphology without altering the overall growth of the plant. The NbBTF3 gene is constitutively expressed and the NbBTF3-GFP fusion protein is primarily targeted to the nucleus. At the cellular level, downregulation of NbBTF3 expression reduced the chloroplast sizes and chlorophyll contents. The affected cells produced excessive amounts of reactive oxygen species. Furthermore, the transcript level of various plastid- and mitochondria-encoded genes was severely reduced in the NbBTF3-depleted leaf cells. These findings indicate that depletion of NbBTF3 activity preferentially affected development and/or physiology of chloroplasts and mitochondria in plants, possibly by hampering efficient translocation of the nascent organellar proteins into the organelles.
    Planta 06/2007; 225(6):1459-69. · 3.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Xyloglucan endotransglucosylase/hydrolase (XTH) has been recognized as a cell wall-modifying enzyme, participating in the diverse physiological roles. From water-stressed hot pepper plants, we isolated three different cDNA clones (pCaXTH1, pCaXTH2, and pCaXTH3) that encode XTH homologs. RT-PCR analysis showed that three CaXTH mRNAs were concomitantly induced by a broad spectrum of abiotic stresses, including drought, high salinity and cold temperature, and in response to stress hormone ethylene, suggesting their role in the early events in the abiotic-related defense response. Transgenic Arabidopsis plants that constitutively expressed the CaXTH3 gene under the control of the CaMV 35S promoter exhibited abnormal leaf morphology; the transgenic leaves showed variable degrees of twisting and bending along the edges, resulting in a severely wrinkled leaf shape. Microscopic analysis showed that 35S-CaXTH3 leaves had increased numbers of small-sized cells, resulting in disordered, highly populated mesophyll cells in each dorsoventral layer, and appeared to contain a limited amount of starch. In addition, the 35S-CaXTH3 transgenic plants displayed markedly improved tolerance to severe water deficit, and to lesser extent to high salinity in comparison with the wild-type plants. These results indicate that CaXTH3 is functional in heterologous Arabidopsis cells, thereby effectively altering cell growth and also the response to abiotic stresses. Although the physiological function of CaXTHs is not yet clear, there are several possibilities for their involvement in a subset of physiological responses to counteract dehydration and high salinity stresses in transgenic Arabidopsis plants.
    FEBS Letters 06/2006; 580(13):3136-44. · 3.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The very long chain fatty acids (VLCFAs) are synthesized by the microsomal fatty acid elongation system in plants. We investigated cellular function of NbECR putatively encoding enoyl-CoA reductase that catalyzes the last step of VLCFA elongation in Nicotiana benthamiana. Virus-induced gene silencing of NbECR produced necrotic lesions with typical cell death symptoms in leaves. In the affected tissues, ablation of the epidermal cell layer preceded disintegration of the whole leaf cell layers, and disorganized cellular membrane structure was evident. The amount of VLCFAs was reduced in the NbECR VIGS lines, suggesting NbECR function in elongation of VLCFAs. The results demonstrate that NbECR encodes a putative enoyl-CoA reductase and that the NbECR activity is essential for membrane biogenesis in N. benthamiana.
    FEBS Letters 09/2005; 579(20):4459-64. · 3.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Retinoblastoma protein (Rb) plays a key role in cell cycle control, cell differentiation, and apoptosis in animals. In this study, we used virus-induced gene silencing (VIGS) to investigate the cellular functions of Rb in higher plants. VIGS of NbRBR1, which encodes the Nicotiana benthamiana Rb homolog, resulted in growth retardation and abnormal organ development. At the cellular level, Rb suppression caused prolonged cell proliferation in tissues that are normally differentiated, which indicates that Rb is a negative regulator of plant cell division. Furthermore, differentiation of the epidermal pavement cells and trichomes was partially retarded, and stomatal clusters formed in the epidermis, likely due to uncontrolled cell division of stomata precursor cells. Rb suppression also caused extra DNA replication in endoreduplicating leaf cells, suggesting a role of Rb in the endocycle. These Rb phenotypes were accompanied by stimulated transcription of E2F and E2F-regulated S-phase genes. Thus, disruption of Rb function in plants leads to ectopic cell division in major organs that correlates with a delay in cell differentiation as well as increased endoreduplication, which indicates that Rb coordinates these processes in plant organ development.
    The Plant Journal 05/2005; 42(2):153-63. · 6.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Most of the proline-rich cell wall glycoprotein genes isolated from higher plants are preferentially expressed in the transmitting tissues of the flower organ. In conducting expressed sequence tag (EST) analysis, which was prepared from 5-day-old early roots of hot pepper (Capsicum annuum L. cv. Pukang), we identified a cDNA clone, pCaPRP1, encoding a putative cell wall proline-rich glycoprotein. CaPRP1 (Mr=28 kDa, pI=9.98) was most closely related to Nicotiana alata NaPRP4 (71%), while most distantly related to soybean PvPRP (37%). The predicted primary structure of CaPRP1 contains a putative N-terminal signal peptide, six repeats of the Lys-Pro-Pro tripeptide, four repeats of a five-amino acid sequence [Pro-(Ser/The)-Pro-Pro-Pro] and one potential N-glycosylation site (Asn-Asn-Ser). In contrast to most proline-rich cell wall glycoprotein genes, CaPRP1 was highly expressed in rapidly elongating very early roots and young leaves as well as developing flower tissues. Although the physiological function of CaPRP1 is not yet clear, there are several possibilities for its role in cell expansion and elongation during early development of hot pepper plants.
    Biochimica et Biophysica Acta 10/2004; 1674(1):103-8. · 4.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Among various abiotic stresses, water deficit is one of the most severe environmental factors responsible for the reduction of crop yield in many parts of the world. By means of the mRNA differential display technique, seven cDNAs (pCa-DIs for Capsicum annuum drought induced) have been isolated that are rapidly induced when hot pepper plants are subjected to water stress (5–20% loss of fresh weight). For all of the isolated Ca-DIs, database search provided significant sequence similarity to previously described genes from different plant species. The predicted proteins encoded by the Ca-DI genes are putatively involved in processes as diverse as primary metabolism, protein degradation, cell wall modification and stress response, suggesting the complexity of cellular responses to drought stress in hot pepper plants. Particularly, we analyzed the detailed structural property and expression pattern of the Ca-DI4 (Ca-LEAL1) gene. Sequence homology studies indicate that Ca-LEAL1 (Mr=19.3 kDa) belongs to a new family of atypical hydrophobic late embryogenesis-abundant-like (LEA-like) proteins. Expression analysis showed that Ca-LEAL1 was strongly activated by drought and salt stresses, and also in response to mechanical wounding in both local and systemic leaves. Moreover, the level of Ca-LEAL1 transcript was rapidly enhanced by exogenous application of ABA and ethylene. These results are consistent with the notion that an atypical hydrophobic Ca-LEAL1 protein is subject to control by diverse environmental factors and that ethylene, in conjunction with ABA, plays an important role in the regulation of the stress gene in hot pepper plants. The possible physiological functions of Ca-LEAL1 as well as other Ca-DI proteins in the adaptive process against drought stress are discussed
    Plant Science. 01/2003;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two cDNAs, pNGPI-1 and pNGPI-2, encoding Nicotiana glutinosa proteinase inhibitor II (PI-II) have been cloned, sequenced and identified. The deduced amino acid sequences are 54–82% identical to those of other plant PI-II. The NGPI-1 protein is composed of eight repeated domains, while NGPI-2 contains six repeated regions, each with a putative reactive site. The expression of NGPI-1 is highly regulated in a developmental- and tissue-specific manner, with the transcript being detected in young leaves and floral organs of N. glutinosa plants. In mature leaves, the NGPI-1 gene is rapidly activated by distinct temporal induction patterns in response to pathogen-related (biotic) and wound-related (abiotic) stresses.
    Biochimica et Biophysica Acta 07/2000; · 4.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two cDNAs, pNGPI-1 and pNGPI-2, encoding Nicotiana glutinosa proteinase inhibitor II (PI-II) have been cloned, sequenced and identified. The deduced amino acid sequences are 54–82% identical to those of other plant PI-II. The NGPI-1 protein is composed of eight repeated domains, while NGPI-2 contains six repeated regions, each with a putative reactive site. The expression of NGPI-1 is highly regulated in a developmental- and tissue-specific manner, with the transcript being detected in young leaves and floral organs of N. glutinosa plants. In mature leaves, the NGPI-1 gene is rapidly activated by distinct temporal induction patterns in response to pathogen-related (biotic) and wound-related (abiotic) stresses.
    Biochimica Et Biophysica Acta-gene Structure and Expression - BBA-GENE STRUCT EXPRESS. 01/2000; 1492(1):211-215.

Publication Stats

218 Citations
28.66 Total Impact Points

Institutions

  • 2000–2008
    • Yonsei University
      • Department of Biology
      Seoul, Seoul, South Korea
  • 2007
    • Korea Research Institute of Bioscience and Biotechnology KRIBB
      • Laboratory of Plant Genomics
      Ansan, Gyeonggi, South Korea