An insertional mutation in the rice PAIR2 gene, the ortholog of Arabidopsis ASY1, results in a defect in homologous chromosome pairing during meiosis
An insertional mutation in the rice PAIR2 gene, the ortholog of Arabidopsis ASY1, results in a defect in homologous chromosome pairing during meiosis
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DOI：
10.1007/s00438-003-0934-z
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发表时间：
2004-03-01
影响因子：
3.1
通讯作者：
Kurata, N
中科院分区：
文献类型：
--
作者：
Nonomura, KI;Nakano, M;Kurata, N
为了阐明在单子叶植物中建立同源染色体配对的遗传系统，我们分离了一个水稻的无杂种突变体，命名为pair2（水稻减数分裂2中的同源配对畸变），其中在pachytene和diakinesis观察到24个完全不配对的单价染色体。该突变是由反转录转座子Tos17的插入引起的，通过与相应的野生型基因的转化证实了该突变的互补。该元件插入的基因与拟南芥的ASY1基因和酿酒酵母的HOP1基因同源。成熟的PAIR2 mRNA和几种剪接变体在野生型生殖组织中高表达，在营养组织中也低表达。原位杂交和BrdU掺入实验表明，PAIR2在雄性和雌性减数分裂细胞中特异性表达增强，而在减数分裂前S期和花粉成熟期则没有。本研究的结果表明，在减数分裂中，PAIR2基因对同源染色体配对至关重要，就像ASY1和HOP1基因一样。该研究还提出了一种可能性，即位于不同染色体上的PAIR2基因的高度同源拷贝实际上是一个假基因。
To elucidate the genetic system that establishes homologous chromosome pairing in monocot plants, we have isolated an asynaptic mutant of rice, designated pair2 (homologous pairing aberration in rice meiosis 2), in which 24 completely unpaired univalents are observed at pachytene and diakinesis. The mutation was caused by an insertion of the retrotransposon Tos17, as demonstrated by complementation of the mutation by transformation with the corresponding wild-type gene. The gene in which the element was inserted is orthologous to the ASY1 gene of Arabidopsis thaliana and the HOP1 gene of Saccharomyces cerevisiae. Mature PAIR2 mRNA and several splicing variants were found to be highly expressed in wild-type reproductive tissues, and lower expression was also detected in vegetative tissues. In situ hybridization and BrdU incorporation experiments revealed that PAIR2 expression is specifically enhanced in male and female meiocytes, but not in those at pre-meiotic S phase or in the pollen maturation stages. The results obtained in this study suggest that the PAIR2 gene is essential for homologous chromosome pairing in meiosis, as in the case of the genes ASY1 and HOP1. The study also suggested the possibility that a highly homologous copy of the PAIR2 gene located on a different chromosome is in fact a pseudogene.