title: Identification of nucleosome assembly protein 1 (NAP1) as an interacting partner of plant ribosomal protein S6 (RPS6) and a positive regulator of rDNA transcription.
abstract: The ribosomal protein S6 (RPS6) is a downstream component of the signaling mediated by the target of rapamycin (TOR) kinase that acts as a central regulator of the key metabolic processes, such as protein translation and ribosome biogenesis, in response to various environmental cues. In our previous study, we identified a novel role of plant RPS6, which negatively regulates rDNA transcription, forming a complex with a plant-specific histone deacetylase, AtHD2B. Here we report that the Arabidopsis RPS6 interacts additionally with a histone chaperone, nucleosome assembly protein 1(AtNAP1;1). The interaction does not appear to preclude the association of RPS6 with AtHD2B, as the AtNAP1 was also able to interact with AtHD2B as well as with an RPS6-AtHD2B fusion protein in the BiFC assay and pulldown experiment. Similar to a positive effect of the ribosomal S6 kinase 1 (AtS6K1) on rDNA transcription observed in this study, overexpression or down regulation of the AtNAP1;1 resulted in concomitant increase and decrease, respectively, in rDNA transcription suggesting a positive regulatory role played by AtNAP1 in plant rDNA transcription, possibly through derepression of the negative effect of the RPS6-AtHD2B complex.
authors.affiliation: Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea.
authors.forename: Ora
authors.initials: O
authors.lastname: Son
authors.affiliation: Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea; Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Sunghan
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea.
authors.forename: Yun-Jeong
authors.initials: YJ
authors.lastname: Shin
authors.affiliation: College of Pharmacy, Sookmyung Women's University, Seoul 140-742, Republic of Korea.
authors.forename: Woo-Young
authors.initials: WY
authors.lastname: Kim
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea. Electronic address: heejkoh@snu.ac.kr.
authors.forename: Hee-Jong
authors.initials: HJ
authors.lastname: Koh
authors.affiliation: Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea. Electronic address: ccheon@sookmyung.ac.kr.
authors.forename: Choong-Ill
authors.initials: CI
authors.lastname: Cheon
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D004275:DNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011523:Protoplasts / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D004275:DNA, Ribosomal; D008164:Luminescent Proteins; D009707:Nucleosomes; C543707:RPS6 protein, Arabidopsis; C054562:yellow fluorescent protein, Bacteria; D019869:Phosphatidylinositol 3-Kinases; C512171:TOR protein, Arabidopsis; C521258:HDT2 protein, Arabidopsis; D006655:Histone Deacetylases; D000251:Adenosine Triphosphatases; C498859:NAP1 protein, Arabidopsis
keywords: Histone deacetylase 2B; Nucleosome assembly protein 1; Ribosomal protein S6; TOR; rDNA transcription