Varterasian M, Lipkowitz S, Karsch-Mizrachi I, Paterson B, Kirsch I
National Cancer Institute-Navy Medical Oncology Branch, National Naval Medical Center, Bethesda, Maryland 20889-5105.
Cell Growth Differ. 1993 Nov;4(11):885-9.
We have identified two new basic domain helix-loop-helix (bHLH) genes in Drosophila melanogaster, DroSCL and DroNHLH. DroSCL was identified because of its homology to the mammalian hematopoietic transcription factor SCL. DroNHLH was similarly identified by homology to NHLH1 and NHLH2, two bHLH genes expressed in the developing mammalian nervous system. A partial DroSCL complementary DNA clone was obtained from an early pupal (5.5-7.5-day) Drosophila library. DroSCL is 73% identical to SCL within the 55-amino acid region of the bHLH domain. A DroNHLH complementary DNA clone was obtained from an early instar (I and II) Drosophila library. Its coding region consists of 162 amino acids and encodes a predicted protein of 18,312 daltons. DroNHLH is 87% identical to NHLH1 and NHLH2 within the bHLH domain. DroSCL and DroNHLH are located on the X chromosome. A 1.7-kilobase DroSCL transcript and a 1.5-kilobase DroNHLH transcript were detected by Northern analysis of total Drosophila RNA. Examination of Drosophila embryos by tissue in situ hybridization reveals restricted expression of both genes in a subset of cells in the developing central nervous system.
我们在黑腹果蝇中鉴定出了两个新的碱性结构域螺旋-环-螺旋（bHLH）基因，即DroSCL和DroNHLH。DroSCL因其与哺乳动物造血转录因子SCL的同源性而被鉴定出来。DroNHLH同样是通过与NHLH1和NHLH2的同源性鉴定出来的，这两个bHLH基因在发育中的哺乳动物神经系统中表达。从早期蛹期（5.5 - 7.5天）的果蝇文库中获得了一个部分DroSCL互补DNA克隆。在bHLH结构域的55个氨基酸区域内，DroSCL与SCL的同源性为73%。从早期幼虫（I和II）果蝇文库中获得了一个DroNHLH互补DNA克隆。其编码区由162个氨基酸组成，编码一个预测分子量为18,312道尔顿的蛋白质。在bHLH结构域内，DroNHLH与NHLH1和NHLH2的同源性为87%。DroSCL和DroNHLH位于X染色体上。通过对果蝇总RNA的Northern分析检测到了一个1.7千碱基的DroSCL转录本和一个1.5千碱基的DroNHLH转录本。通过组织原位杂交对果蝇胚胎进行检查，发现这两个基因在发育中的中枢神经系统的一部分细胞中表达受限。
