Alternative splicing can generate multiple mRNAs that differ in their untranslated regions or coding sequences, and these differences might affect mRNA stability or result in different protein isoforms with diverse functions and/or localizations. In this study, we isolated a sterile mutant in rice with abnormal meiosis of microspore mother cells and megaspore mother cells that carried a point mutation in OsRAD1 gene. Cloning of OsRAD1 cDNAs revealed three transcript variants, named as OsRAD1.1, OsRAD1.2 and OsRAD1.3, respectively, which were derived from alternative splicing of the last intron. Proteins derived from the three transcripts were mostly identical except the difference in the very C-terminal domain. The three transcripts exhibited similar expression patterns in various tissues, but the expression level of OsRAD1.1 was the highest. Specific knockout of OsRAD1.1 led to sterility, while knockout of OsRAD1.2 and OsRAD1.3 together did not change the plant fertility. Overexpression of OsRAD1.2 and OsRAD1.3 cDNAs in OsRAD1.1-specific mutant did not complement the plant fertility. Yeast two-hybrid assay showed that OsRAD1.1, but not OsRAD1.2 and OsRAD1.3, interacted with the three other meiosis proteins OsHUS1, OsRAD9 and OsRAD17, suggesting that the C-terminal domain of OsRAD1.1 is critical for the protein function.

选择性剪接可产生在其非翻译区或编码序列方面不同的多个mRNA，这些差异可能影响mRNA的稳定性或导致具有不同功能和/或定位的不同蛋白同工型。在这项研究中，我们从水稻中分离出一个无菌突变体，该突变体的小孢子母细胞和大孢子母细胞减数分裂异常，并在OsRAD1基因中发生了点突变。OsRAD1 cDNA的克隆揭示了三个转录物变体，分别为OsRAD1.1，OsRAD1.2和OsRAD1.3分别来自最后一个内含子的可变剪接。源自这三个转录本的蛋白质几乎完全相同，只是在C末端结构域不同。这三个转录本在各种组织中表现出相似的表达模式，但OsRAD1.1的表达水平最高。特定敲除OsRAD1.1导致不育，而同时敲除OsRAD1.2和OsRAD1.3不会改变植物的育性。的表达OsRAD1.2和OsRAD1.3在cDNA中OsRAD1.1特异性突变体不能补充植物的育性。酵母两杂交试验表明，OsRAD1.1，而不是OsRAD1.2和OsRAD1.3，与其他三种减数分裂蛋白OsHUS1，OsRAD9和OsRAD17相互作用，这表明OsRAD1.1的C端结构域对该蛋白至关重要功能。