| Summary: | 碩士 === 國立中興大學 === 生物科技學研究所 === 92 === Abstract
? In plants, intracellular Ca2+ levels are modulated in response to various biotic or abiotic signals. The calcium-dependent calmodulin-independent protein kinases (CDPKs) play critical roles in transducing calcium signals by reversibly phosphorylating substrate proteins. Encoded by a multigene family, CDPKs had been found expressed with distinct profiles or localized to specific subcellular locations, indicating their roles in various physiological responses. OSCK1 and OSCK2 are pollen-specific CDPK genes isolated from rice. As calcium was known to play crucial roles in pollen development, we had used the kinase domain of OSCK1 as a bait in yeast two-hybrid screens to peruse the OSCK1-interaction proteins (OIPs). Blast search of GenBank predicted that OIP1, 13, 30, 18 and 28 encoding proteins homologous to a Hsp70/Hsp90 organizing-like protein (C terminal half only), a phosphatidylinositol phosphatidylcholine transfer protein (C-terminal only), a RuvB-like DNA helicase (near full-length) and two CDPKs, respectively. In this study, analyses of gene expression profiles by RT-PCR suggested that OIP1 were expressed in various tissues. OIP13, OIP18 and OIP28 were expressed predominantly in spikelet and mature pollen, although OIP28 was detected also in callus. On the opposite, OIP30 was highly expressed in the vegetative tissues but surprisingly, barely detectable in the mature pollen. Moreover, Gene-transformed rice putatively interfere the endogenous OSCK1 and OSCK2 expressions resulted in early flowering, long rachilla and grain loss on rachis segment etc., if compared with vector-transformed rice.
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