Ghabrial A, Ray R P, Schüpbach T
Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
Genes Dev. 1998 Sep 1;12(17):2711-23. doi: 10.1101/gad.12.17.2711.
okra (okr), spindle-B (spnB), and spindle-D (spnD) are three members of a group of female sterile loci that produce defects in oocyte and egg morphology, including variable dorsal-ventral defects in the eggshell and embryo, anterior-posterior defects in the follicle cell epithelium and in the oocyte, and abnormalities in oocyte nuclear morphology. Many of these phenotypes reflect defects in grk-Egfr signaling processes, and can be accounted for by a failure to accumulate wild-type levels of Gurken and Fs(1)K10. We have cloned okr and spnB, and show that okr encodes the Drosophila homolog of the yeast DNA-repair protein Rad54, and spnB encodes a Rad51-like protein related to the meiosis-specific DMC1 gene. In functional tests of their role in DNA repair, we find that okr behaves like its yeast homolog in that it is required in both mitotic and meiotic cells. In contrast, spnB and spnD appear to be required only in meiosis. The fact that genes involved in meiotic DNA metabolism have specific effects on oocyte patterning implies that the progression of the meiotic cell cycle is coordinated with the regulation of certain developmental events during oogenesis.
okra(okr)、纺锤体-B(spnB)和纺锤体-D(spnD)是一组雌性不育位点的三个成员,这些位点会导致卵母细胞和卵子形态出现缺陷,包括卵壳和胚胎中可变的背腹缺陷、卵泡细胞上皮和卵母细胞中的前后缺陷以及卵母细胞核形态异常。这些表型中的许多都反映了grk-Egfr信号传导过程中的缺陷,并且可以通过无法积累野生型水平的Gurken和Fs(1)K10来解释。我们已经克隆了okr和spnB,并表明okr编码酵母DNA修复蛋白Rad54的果蝇同源物,而spnB编码与减数分裂特异性DMC1基因相关的Rad51样蛋白。在对它们在DNA修复中的作用进行功能测试时,我们发现okr的行为与其酵母同源物相似,即在有丝分裂和减数分裂细胞中都需要它。相比之下,spnB和spnD似乎仅在减数分裂中需要。参与减数分裂DNA代谢的基因对卵母细胞模式形成有特定影响,这一事实意味着减数分裂细胞周期的进程与卵子发生过程中某些发育事件的调节是协调的。