pTAC10, a Key Subunit of Plastid-Encoded RNA Polymerase, Promotes Chloroplast Development.
Regulation of photosynthetic gene expression by plastid-encoded RNA polymerase (PEP) is essential for chloroplast development. The activity of PEP largely relies on at least 12 PEP-associated proteins (PAPs) encoded in the nuclear genome of plant cells. A recent model proposed that these PAPs regulate the establishment of the PEP complex through broad PAP-PEP or PAP-PAP interactions. In this study, we identified the Arabidopsis (Arabidopsis thaliana) seedling-lethal mutantptac10-1, which has defects in chloroplast development, and found that the mutant phenotype is caused by the suppression ofPLASTID S1 RNA-BINDING DOMAIN PROTEIN(pTAC10/PAP3). Analysis of the heterozygous mutant andpTAC10-overexpressing transgenic plants indicated that the expression level ofpTAC10is tightly linked to chloroplast development. Characterization of the interaction of pTAC10 with PAPs revealed that pTAC10 interacts with other PAPs, such as FSD2, FSD3, TrxZ, pTAC7, and pTAC14, but it does not interact with PEP core enzymes, such as rpoA and rpoB. Analysis of pTAC10 interactions using truncated pTAC10 proteins showed that the pTAC10 carboxyl-terminal region downstream of the S1 domain is involved in the pTAC10-PAP interaction. Furthermore, overexpression of truncatedpTAC10slacking the C-terminal regions downstream of the S1 domain could not rescue theptac10-1mutant phenotype and induced an abnormal whitening phenotype in Columbia-0 plants. Our observations suggested that these pTAC10-PAP interactions are essential for the formation of the PEP complex and chloroplast development.
Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea (S.H.C., S.L., T.Y.U., Y.D.C., G.J.); and.|Graduate School of International Agricultural Technology and Crop Biotechnology Institute/Green BioScience and Technology, Seoul National University, Pyeongchang 232-916, Korea (J.-K.K.).
Sun Hyun
http://orcid.org/0000-0001-6196-4098
SH
Chang
Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea (S.H.C., S.L., T.Y.U., Y.D.C., G.J.); and.|Graduate School of International Agricultural Technology and Crop Biotechnology Institute/Green BioScience and Technology, Seoul National University, Pyeongchang 232-916, Korea (J.-K.K.).
Sangyool
http://orcid.org/0000-0003-1670-0928
S
Lee
Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea (S.H.C., S.L., T.Y.U., Y.D.C., G.J.); and.|Graduate School of International Agricultural Technology and Crop Biotechnology Institute/Green BioScience and Technology, Seoul National University, Pyeongchang 232-916, Korea (J.-K.K.).
Tae Young
http://orcid.org/0000-0002-4787-6400
TY
Um
Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea (S.H.C., S.L., T.Y.U., Y.D.C., G.J.); and.|Graduate School of International Agricultural Technology and Crop Biotechnology Institute/Green BioScience and Technology, Seoul National University, Pyeongchang 232-916, Korea (J.-K.K.).
Ju-Kon
http://orcid.org/0000-0001-8905-7617
JK
Kim
Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea (S.H.C., S.L., T.Y.U., Y.D.C., G.J.); and.|Graduate School of International Agricultural Technology and Crop Biotechnology Institute/Green BioScience and Technology, Seoul National University, Pyeongchang 232-916, Korea (J.-K.K.).
Yang
http://orcid.org/0000-0003-4706-5154
Y
Do Choi
Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea (S.H.C., S.L., T.Y.U., Y.D.C., G.J.); and yk3@snu.ac.kr.|Graduate School of International Agricultural Technology and Crop Biotechnology Institute/Green BioScience and Technology, Seoul National University, Pyeongchang 232-916, Korea (J.-K.K.) yk3@snu.ac.kr.
Geupil
http://orcid.org/0000-0001-8637-1782
G
Jang
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism* / Q000648:ultrastructure; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D030821:Plants, Genetically Modified; D018087:Plastids / Q000201:enzymology*; D011485:Protein Binding
D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; C000627973:pTAC10 protein, Arabidopsis; D012321:DNA-Directed RNA Polymerases