Processing of meiotic DNA recombination intermediates in Arabidopsis thaliana

在第一个资助期，我们更详细地分析了RTR复合体AtTOP3α和AtRMI1的成员，研究了这些蛋白质的单个结构域在体细胞和减数分裂重组中的功能作用，以及与已知的减数分裂重组基因的遗传相互作用。此外，我们还表征了最近发现的RTR复合体成员AtRMI2的同源物在基因组稳定性和减数分裂中的功能。关于我们通过RTR复合体抑制超重组的工作，我们开始分析这些基因的遗传或物理相互作用伙伴的潜在同源物。在这里，我们能够鉴定Fanconi贫血蛋白FANCM和动物抗重组酶RTEL1的植物同源物。在初步工作中，我们可以证明AtFANCM在停滞的复制叉处参与抑制体细胞HR，其途径与RECQ4A平行。我们发现AtFANCM在减数分裂重组中有一个令人惊讶的功能，它的突变可以抑制Atmsh4突变体的不育表型。这表明AtFANCM在调控非交叉和交叉输出之间的路径选择中发挥了作用-在减数分裂重组中，我们希望使用一些遗传学和细胞学方法进一步定义这种重组。拟南芥具有两个不相关的反重组酶AtSRS2和AtRTEL1，它们似乎是冗余作用的。由于rtel1突变植株表现出育性缺陷，我们也想研究该解旋酶在减数分裂中的可能功能。

During the first funding period, we analyzed the members of the RTR complex AtTOP3α and AtRMI1 in more detail, addressing the functional role of individual domains of the proteins in somatic and meiotic recombination as well as the genetic interaction with known meiotic recombination genes. Additionally we characterized the function of a homolog of a more recently discovered member of the RTR complex, AtRMI2, in genome stability and meiosis. In relation to our work on hyperrecombination suppression through the RTR complex, we started to analyze potential homologs of genetic or physical interaction partners of these genes. Here, we were able to identify plant homologs of the Fanconi anemia protein FANCM and of the animal antirecombinase RTEL1. In preliminary work, we could show that AtFANCM is involved in the suppression of somatic HR at stalled replication forks in a pathway parallel to that of RECQ4A. We discovered a surprising function of AtFANCM in meiotic recombination, where its mutation can suppress the sterile phenotype of Atmsh4 mutants. This points to a role of AtFANCM in the regulation of pathway choice between noncrossover and crossover out-comes in meiotic recombination that we would like to define further using a number of genetic and cytological methods. Arabidopsis possesses two unrelated antirecombinases AtSRS2 and AtRTEL1 that seem to act redundantly. Since rtel1 mutant plants show a fertility defect, we would like to investi-gate possible functions of this helicase in meiosis as well.