A functional component of the transcriptionally active chromosome complex, Arabidopsis pTAC14, interacts with pTAC12/HEMERA and regulates plastid gene expression.
The SET domain-containing protein, pTAC14, was previously identified as a component of the transcriptionally active chromosome (TAC) complexes. Here, we investigated the function of pTAC14 in the regulation of plastid-encoded bacterial-type RNA polymerase (PEP) activity and chloroplast development. The knockout of pTAC14 led to the blockage of thylakoid formation in Arabidopsis (Arabidopsis thaliana), and ptac14 was seedling lethal. Sequence and transcriptional analysis showed that pTAC14 encodes a specific protein in plants that is located in the chloroplast associated with the thylakoid and that its expression depends on light. In addition, the transcript levels of all investigated PEP-dependent genes were clearly reduced in the ptac14-1 mutants, while the accumulation of nucleus-encoded phage-type RNA polymerase-dependent transcripts was increased, indicating an important role of pTAC14 in maintaining PEP activity. pTAC14 was found to interact with pTAC12/HEMERA, another component of TACs that is involved in phytochrome signaling. The data suggest that pTAC14 is essential for proper chloroplast development, most likely by affecting PEP activity and regulating PEP-dependent plastid gene transcription in Arabidopsis together with pTAC12.
College of Life Sciences, Nanjing Normal University, Jiangsu 210046, China.
Zhi-Ping
ZP
Gao
Qing-Bo
QB
Yu
Tuan-Tuan
TT
Zhao
Qian
Q
Ma
Guo-Xiang
GX
Chen
Zhong-Nan
ZN
Yang
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D008027:Light; D008780:Methyltransferases; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D018087:Plastids / Q000235:genetics*; D025941:Protein Interaction Mapping; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020524:Thylakoids / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D018744:DNA, Plant; D012333:RNA, Messenger; D018749:RNA, Plant; D014157:Transcription Factors; D008780:Methyltransferases; C581072:pTAC14 protein, Arabidopsis; D012321:DNA-Directed RNA Polymerases