论文部分内容阅读
玉米S型细胞质雄性不育系(CMS-S)及其近等基因恢复系是研究核-质互作机制的重要遗传资源和理想模式体系.目前认为,CMS-S花粉败育是由其线粒体内细胞质不育基因orf355-orf77表达的毒性蛋白引起,而核育性恢复基因Rf3可通过引发orf355-orf77转录本的降解而解除其毒性作用,使花粉育性得以恢复.本研究采用Northern杂交和3’RACE技术确定了orf355-orf77转录本的剪切位点,并发现在育性恢复的花粉中,orf355-orf77转录本被剪切成小片段之后聚合了poly(A)序列,推测这一过程加速了mRNA分子的降解,是育性恢复的关键环节.利用生物信息学方法分析了orf355-orf77转录本6个剪切位点的侧翼序列,发现在剪切位点下游10个碱基的位置均含有5’-CCACA-3’序列,推测该序列受到特定功能蛋白的识别,然后募集核酸内切酶对其进行剪切.研究结果可为揭示玉米CMS-S育性恢复机理提供重要的理论依据.
S-type cytoplasmic male sterility (CMS-S) and its near-isogenic restorer lines are important genetic resources and ideal model systems for studying the nuclear-physic interaction mechanism. Now it is believed that CMS-S pollen abortion is caused by its mitochondria Orf355-orf77, and the nuclear fertility restorer gene Rf3 can release its toxicity by inducing the degradation of orf355-orf77 transcript, so that the pollen fertility can be restored.In this study, Northern hybridization and The 3’RACE technique identified the cleavage site of the orf355-orf77 transcript and found that the poly (A) sequence was polymerized after orf355-orf77 transcripts were cut into small fragments in fertile restored pollen, suggesting that this process Accelerate the degradation of mRNA molecules is a key part of fertility restoration.By using bioinformatics analysis of the orf355-orf77 transcripts of the six cleavage site flanking sequences found in the cutting site downstream of the 10-base position All of which contained 5’-CCACA-3 ’sequence, which was presumed that the sequence was recognized by a specific functional protein and then raised with endonuclease to cut it.The research results may provide an important theory to reveal the fertility restoration mechanism of CMS-S in maize in accordance with.