The rice OsRad21-4, an orthologue of yeast Rec8 protein, is required for efficient meiosis.
In yeast, Rad21/Scc1 and its meiotic variant Rec8 are key players in the establishment and subsequent dissolution of sister chromatid cohesion for mitosis and meiosis, respectively, which are essential for chromosome segregation. Unlike yeast, our identification revealed that the rice genome has 4 RAD21-like genes that share lower than 21% identity at polypeptide levels, and each is present as a single copy in this genome. Here we describe our analysis of the function of OsRAD21-4 by RNAi. Western blot analyses indicated that the protein was most abundant in young flowers and less in leaves and buds but absent in roots. In flowers, the expression was further defined to premeiotic pollen mother cells (PMCs) and meiotic PMCs of anthers. Meiotic chromosome behaviors were monitored from male meiocytes of OsRAD21-4-deficient lines mediated by RNAi. The male meiocytes showed multiple aberrant events at meiotic prophase I, including over-condensation of chromosomes, precocious segregation of homologues and chromosome fragmentation. Fluorescence in situ hybridization experiments revealed that the deficient lines were defective in homologous pairing and cohesion at sister chromatid arms. These defects resulted in unequal chromosome segregation and aberrant spore generation. These observations suggest that OsRad21-4 is essential for efficient meiosis.
Zhang
Liangran
L
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Research Center of Molecular & Developmental Biology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Tao
Jiayi
J
Wang
Shunxin
S
Chong
Kang
K
Wang
Tai
T
D000595:Amino Acid Sequence; D002470:Cell Survival; D002842:Chromatids / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone; D032461:Chromosomes, Plant / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D035264:Flowers / Q000166:cytology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008540:Meiosis / Q000502:physiology*; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D051479:Plant Infertility; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D002868:Chromosomal Proteins, Non-Histone; D018076:DNA, Complementary; D010940:Plant Proteins; C502898:REC8 protein, S cerevisiae; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins