SPO11 dependent initiation of meiotic double strand breaks in Arabidopsis thaliana

在几乎所有的真核生物中，减数分裂重组过程都依赖于由减数分裂特异性转酯酶SPO 11引发的双链断裂（DSB）。在动物和真菌中，一个单一的SPO 11基因是足够的，而在植物中，其中两个，AtSPO 11 -1和2，是必不可少的减数分裂DSB的启动。这两种SPO 11蛋白在功能形式上都是必需的，否则在拟南芥中不进行DSB诱导，并且由于减数分裂期间的随机染色体分离，植物几乎不育。因此，我们想研究这两个SPO 11基因在拟南芥中的功能是否是物种和/或序列特异性的，或者它们是否可以被拟南芥SPO 11基因互补，其中部分序列在两个基因之间互换（交换DNA）。此外，我们将使用来自陆地植物（番木瓜和小立碗藓）的正向同源SPO 11 -1和-2基因以及来自较小相关生物（莱茵衣藻和小家鼠）的cDNA，用于拟南芥SPO 11突变体的异源互补。使用异源基因或cDNA和截短或部分交换的拟南芥DNA互补的SPO 11 -1和2突变体，我们应该能够回答以下问题。SPO 11蛋白的特定序列是否是减数分裂DSB正确起始所必需的，哪个序列区域决定了SPO 11 -1和2之间的差异？

The meiotic recombination process depends in nearly all eukaryotes on the initiation of double strand breaks (DSBs) by SPO11, a meiosis specific transesterase. In animals and fungi a single SPO11 gene is sufficient whereas in plants two of them, AtSPO11-1 and 2, are essential for the initiation of meiotic DSBs. Both SPO11 proteins are necessary in a functional form otherwise no DSB induction is performed in Arabidopsis and the plants are nearly sterile due to random chromosome segregation during meiosis. Therefore, we want to investigate whether the functions of these two SPO11 genes in Arabidopsis thaliana are species- and/or sequence-specific or if they can be complemented by Arabidopsis SPO11 genes in which parts of the sequences are interchanged between both genes (swap DNAs). Furthermore, we will use the orthologous SPO11-1 and -2 genes from land plants (Carica papaya and Physcomitrella patens) and cDNAs from lesser related organisms (Chlamydomonas reinhardtii and Mus musculus) for heterologous complementation of SPO11 mutants from Arabidopsis. Using heterologous genes or cDNAs and truncated or partially swapped DNAs of Arabidopsis for the complementation of SPO11-1 and 2 mutants, we should be able to answer the following questions. Is a specific sequence of the respective SPO11 protein necessary for proper initiation of meiotic DSBs and which sequence region is defining the difference between SPO11-1 and 2?