Devlin R H, Bingham B, Wakimoto B T
Department of Zoology NJ-15, University of Washington, Seattle 98195.
Genetics. 1990 May;125(1):129-40. doi: 10.1093/genetics/125.1.129.
The light (lt) gene is located in the centromeric heterochromatin of chromosome 2 of Drosophila melanogaster. This gene is necessary for normal levels of pigmentation in a number of adult and larval tissues and is required for viability. Hybrid dysgenic and X-ray induced mutations have been used to identify the gene and compare its organization to that of euchromatic genes. Molecular mapping of lt mutations and its major transcripts has shown that the lt gene is at least 17 kb. By injecting cosmid clones that include this region into lt mutant embryos, we have defined a 30-kb region that can transiently rescue the pigmentation defect in the Malpighian tubules. The major transcription unit of this gene is comprised of exons that are single copy. It is unusual in its organization in having a heterogeneous array of middle repetitive DNA sequences within its intronic and flanking regions.
光（lt）基因位于黑腹果蝇2号染色体的着丝粒异染色质中。该基因对于许多成虫和幼虫组织正常水平的色素沉着是必需的，并且对于生存力也是必需的。杂种不育和X射线诱导的突变已被用于鉴定该基因，并将其结构与常染色质基因的结构进行比较。lt突变及其主要转录本的分子图谱显示，lt基因至少有17 kb。通过将包含该区域的黏粒克隆注射到lt突变胚胎中，我们确定了一个30 kb的区域，该区域可以暂时挽救马尔皮基氏小管中的色素沉着缺陷。该基因的主要转录单位由单拷贝的外显子组成。它的结构不寻常，在其内含子和侧翼区域内有一系列异质的中度重复DNA序列。
