Poster: Reproductive development
Abs #
357: RNAi-mediated silencing of OsRAD, a member of novel subclass of the RAD2/XPG nuclease family causes pollen abortion and male sterility in rice.
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Presenter: |
Moritoh, Satoru , s-morito@bs.aist-nara.ac.jp |
Authors | Moritoh, Satoru (A) Kawahara, Mihoko (A) Izawa, Takeshi (A) (B) Shimamoto, Ko (A) | | Affiliations: |
(A): Nara Institute of Science and Technology (NAIST)
(B): Present address: National Institute of Agrobiological Sciences
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Nucleases play important roles in nucleic acid metabolism in every organism, and are involved in a variety of basic cellular and genetic processes. Using rice Ac transposon tagged lines we cloned one of the RAD2/XPG nuclease family members in rice. We named this gene OsRAD. The OsRAD gene has the conserved XPG-N and XPG-I domains and shares similarity with three subclasses of RAD2/XPG nuclease family, RAD2/XPG, FEN1/RAD27, and EXO1, which function in DNA repair, DNA replication, and recombination. Database searches and phylogenetic analyses suggest that OsRAD gene is a member of novel subclass of the RAD2/XPG nuclease family and putative counterparts exist in humans, mice, Drosophila, Arabidopsis and many higher plants. However, the information about these genes is very limited. Therefore, the purpose of this study was to characterize the function of the OsRAD gene in rice. RT-PCR analysis showed that it was expressed in the leaf, root, and flower. A GFP fusion protein of OsRAD was localized in the nucleus. For functional analysis studies, we generated rice OsRAD-RNAi transgenic cell cultures and plants with silenced OsRAD expression. Many of OsRAD-RNAi plants displayed low fertilities and some of them were male sterile. Iodine staining and transverse sections of anthers of these OsRAD-RNAi plants revealed the absence of mature pollen. Normal male meiosis was observed but early male microspores were affected in these OsRAD-RNAi plants. Our results suggest that the OsRAD gene may play an essential role in rice male microspore development. We are now trying to examine a nuclease activity of recombinant OsRAD protein.
