Arabidopsis GLUTAMINE-RICH PROTEIN23 is essential for early embryogenesis and encodes a novel nuclear PPR motif protein that interacts with RNA polymerase II subunit III.
Precise control of gene expression is critical for embryo development in both animals and plants. We report that Arabidopsis thaliana GLUTAMINE-RICH PROTEIN23 (GRP23) is a pentatricopeptide repeat (PPR) protein that functions as a potential regulator of gene expression during early embryogenesis in Arabidopsis. Loss-of-function mutations of GRP23 caused the arrest of early embryo development. The vast majority of the mutant embryos arrested before the 16-cell dermatogen stage, and none of the grp23 embryos reached the heart stage. In addition, 19% of the mutant embryos displayed aberrant cell division patterns. GRP23 encodes a polypeptide with a Leu zipper domain, nine PPRs at the N terminus, and a Gln-rich C-terminal domain with an unusual WQQ repeat. GRP23 is a nuclear protein that physically interacts with RNA polymerase II subunit III in both yeast and plant cells. GRP23 is expressed in developing embryos up to the heart stage, as revealed by beta-glucuronidase reporter gene expression and RNA in situ hybridization. Together, our data suggest that GRP23, by interaction with RNA polymerase II, likely functions as a transcriptional regulator essential for early embryogenesis in Arabidopsis.
Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China.
Yong-He
YH
Ding
Nai-You
NY
Liu
Zuo-Shun
ZS
Tang
Jie
J
Liu
Wei-Cai
WC
Yang
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D017124:Conserved Sequence; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism*; D015183:Restriction Mapping; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism*
D029681:Arabidopsis Proteins; C511742:GRP23 protein, Arabidopsis; D010446:Peptide Fragments; D021122:Protein Subunits; D014157:Transcription Factors; D012319:RNA Polymerase II