Matsubayashi H, Juni N, Usui K, Hori S H, Tobari Y N
Department of Biology, Faculty of Science, Tokyo Metropolitan University, Japan.
Mol Gen Genet. 1991 Jun;227(2):165-72. doi: 10.1007/BF00259667.
A series of transposon-induced optic morphology (Om) mutants found in a hypermutable marker stock of Drosophila ananassae provides a useful system for analyzing the molecular mechanism of eye morphogenesis. In the present study, one of the 25 Om loci so far reported, Om(2D), has been subjected to histological and molecular analyses as a first step toward understanding the role of Om genes in eye morphogenesis. Histological abnormalities observed during eye morphogenesis of the mutant, i.e. cell death within the eye-antennal discs of third instar larvae, and loss of the lamina, disorganized ommatidia and atrophied optic lobes in adults, were all comparable to those reported with various eye morphology mutants of D. melanogaster. Approximately 25 kb of genomic DNA including the Om (2D) locus was cloned by tom tagging. Southern blot and cloning analyses of two alleles of the Om (2D) locus revealed that insertions of the tom element occurred at three sites within 359 bp; two tandemly arrayed toms sharing one long terminal repeat at the junction and an internally deleted tom were present 359 bp apart from each other in Om (2D) 63, while a single tom in reverse orientation was present within the 359 bp in Om (2D) 10a. Host DNA sequences at the three insertion sites were TATAT or AATAT, and ATAT was duplicated upon the tom insertion.(ABSTRACT TRUNCATED AT 250 WORDS)
在果蝇黑腹果蝇的一个超易变标记品系中发现的一系列转座子诱导的视觉形态（Om）突变体，为分析眼睛形态发生的分子机制提供了一个有用的系统。在本研究中，作为了解Om基因在眼睛形态发生中作用的第一步，迄今报道的25个Om位点之一Om(2D)已接受组织学和分子分析。在突变体眼睛形态发生过程中观察到的组织学异常，即三龄幼虫眼触角盘中的细胞死亡，以及成虫中神经毡的缺失、小眼排列紊乱和视神经叶萎缩，均与黑腹果蝇各种眼睛形态突变体报道的异常情况相当。通过转座子标签法克隆了包括Om(2D)位点在内的约25 kb基因组DNA。对Om(2D)位点的两个等位基因进行Southern印迹和克隆分析表明，转座子元件插入发生在359 bp内的三个位点；在Om(2D)63中，两个串联排列的转座子在连接处共享一个长末端重复序列，一个内部缺失的转座子彼此相距359 bp，而在Om(2D)10a中，一个反向的单个转座子存在于359 bp内。三个插入位点的宿主DNA序列为TATAT或AATAT，转座子插入时ATAT会重复。（摘要截短于250字）
