Genetical and molecular characterization of divers in Drosophila melanogaster

潜水员位于X染色体的8D8-9区域。强等位基因有更短、更暗的翅膀，它的前盾片和后盾片都是弯曲的。与黄色突变相结合，它产生了卷曲的翅膀。然而，Dvr84b等较弱的等位基因不能与没有Y的野生型区分开来。通过P元件的再动员实验分析了三个P插入的DVR等位基因。证实这些DVR突变是由P-LACW插入引起的，通过本试验独立获得了三个致死株，并将它们的致死性定位在8D8-9上。聚合酶链式反应和Southern分析表明，在P-插入位点附近有少量缺失。因此，DVR的功能丧失表型是致命的。致死期为1龄或2龄幼虫。从3个插入P-LACW的DVR等位基因中克隆了DVR的基因组区域。它们都在相同的位置以相同的方向插入了P-LACW。我在P-插入前后扩增了约70kb的基因组图谱。该区域存在许多类似重复序列的微卫星。虽然P-插入附近的20kb区域被用于Northern blotting和cDNA筛选探针，但我没有检测到任何转录本。DVR的转录水平似乎很低。众所周知，DVR与叉子和Scute以及黄色都有互动，但他们的互动没有被观察到。我还表明，黄色的色素沉着水平与DVR翅膀的表型没有直接的相关性。通过这些实验，我发现一株携带Y+Y染色体的菌株可以诱导后期致死(就在羽化后)。这种致死性是由DVR和Y染色体引起的，因为所有的DVR+回复株都没有表现出这种致死性，而提取的Y+Y染色体仍然诱导了这种致死性。遗传学数据表明，复制的y+基因对这种致命性没有影响，rDNA基因在这条Y染色体上被放大。

divers is located on the 8D8-9 region of the X chromosome. Strong alleles have shorter, darker wings and its anterior and post-scutellars are bowed in. In combination with yellow mutation, it gives curled wings. However, weaker alleles such as dvr84b cannot be distinguished from a wild type without y. three P-inserted dvr alleles were analyzed by the re-mobilization experiment of their P-elements. It was confirmed that these dvr mutations were caused by the P-lacW insertion, three lethal strains were obtained independently by this test and their lethality were mapped on the 8D8-9. PCR and Southern analysis of them showed that there are small deletions near the P-insertion site. Therefore, loss-of -function phenotype of dvr is lethal. The lethal stage is the first or the second instar larval period. The genomic region of the dvr had been cloned from three P-lacW inserted dvr alleles. All of them have P-lacW insertion at the same site with the same orientation. I have expanded the genomic map about 70 kb around P-insertion. Many micro-satellite like repeated sequences exist in this region. Although the 20 kb region around P-insertion was used for the Northern blotting and cDNA screening probe, I could not detect any transcripts. The transcription level of dvr seems to be low. The dvr is known to interact with forked and scute as well as yellow, but their interaction was not observed. I also showed that the pigmentation level of yellow does not directly correlate with dvr wing phenotype. Through these experiments, I have found a strain carrying y+Y chromosome induce the late stage lethality (just after eclosion). This lethality is caused by dvr and Y chromosome because all of dvr+revertants did not show such lethality and the extracted y+Y chromosome still induced it. Genetical data suggest that the duplicated y+gene has no effect for this lethality and rDNA genes are magnified on this Y chromosome.