摘要
以水稻 (OryzasativaL .)精细胞与二细胞花粉的差减文库中得到的在精细胞中优势表达的克隆作为探针 ,筛选水稻精细胞cDNA文库 ,得到对应的两个全长cDNA克隆。序列分析表明两个全长cDNA阳性克隆长度分别为2 2 78bp和 2 4 37bp ,共同拥有一个由 5 79个氨基酸组成的开放读码框 ,分子量为 6 6 .7kD ,等电点为 4 .885。在Gen Bank中比较显示与拟南芥的肌球重链蛋白有一定的同源性 (46 % ) ,并具有肌球蛋白特色的结构域。资料显示肌球蛋白在高等植物生殖发育过程中起着重要作用。Southern杂交结果表明此基因在水稻基因组中以单拷贝形式存在。Northern杂交结果显示RSSG5 8基因在水稻精细胞中表达量很高 ,在其他组织和细胞中未检测到表达 ,同时还表明在精细胞中存在两类大小不同的转录本。用更为灵敏的RT_PCR方法进行检测分析表明此基因在叶、花粉母细胞期幼穗、单细胞花粉、二细胞花粉、成熟花粉、授粉子房和精细胞中均有表达 ,但在精细胞中表达量远远高于其他组织细胞 。
Myosins, a large family of structurally diverse mechanoenzymes, which, upon interaction with actin filaments, convert energy from ATP hydrolysis into mechanical force, play an important role in male reproductive processes. In this study we report the rice ( Oryza sativa L.) RSSG58 gene, which was cloned from the cDNA library of rice sperm cells by using sperm cell mainly expression subtractive clone as probe. This gene encodes a putative 66.7 W polypeptide, which shows similarity to the myosin heavy chain of Arabidopsis thaliana, and consists of 579 amino acids with an isoelectric point (pI) of 4.885. RSSG58, which is a member of a divergent gene family, generates transcripts of 2 278 bp and 2 437 bp that differ only in their polyadenylation sites. Southern hybridization showed that RSSG58 has only one copy in rice genome and RSSG58 transcripts are most abundant in sperm cells, with two distinct signals. The RT-PCR analysis indicated that the transcriptions of the RSSG58 gene were various in the different development stages and tissues. The greatest accumulation of RSSG58 mRNA was detected in sperm cells, while weaker expression was detected in leaves, microspore mother cells, unicellular microspore pollen stage, two-cell stage pollens, mature pollens and pollinated ovaries. These results suggest that RSSG58 is especially abundantly expressed in rice sperm cells.
基金
国家自然科学基金 (3 0 2 70 0 90 )
教育部博士点基金 (980 610 0 1)
四川省重点科研项目~~
