Conserved arrangement of nested genes at the Drosophila Gart locus.
Conserved arrangement of nested genes at the Drosophila Gart locus.
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果蝇 Gart 基因座嵌套基因的保守排列。
DOI：
10.1093/genetics/117.4.711
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发表时间：
1987
期刊：
影响因子：
3.3
通讯作者：
Eghtedarzadeh,MK
中科院分区：
文献类型：
--
作者：
Henikoff,S;Eghtedarzadeh,MK
果蝇黑腹果蝇Gartgene在嘌呤新合成途径中编码三种酶活性。对初级转录本的交替处理导致合成两个重叠的多肽。这两种多肽的编码序列都被一个内含子打断，该内含子包含一个在相反DNA链上编码的功能性角质层蛋白基因。在这里，我们表明，这种嵌套组织也存在于一个远亲物种假黑果蝇的同源基因座上。在这两个物种中，内含子角质层基因在游荡的幼虫和预蛹中都有表达。值得注意的是，在包含角质层基因的内含子中有24个不同的高度保守的非编码片段。这些基因位于转录起始的上游，在3‘末端，甚至在单个内含子基因内含子内。嘌呤基因中的其他内含子，包括发生替代加工的内含子，没有显示出这样的同源性。似乎至少有一些保守的非编码区参与了角质层基因的高水平发育表达。我们讨论了共享顺式作用调控位点可能增强这两个基因的转录并帮助解释它们的嵌套排列的可能性。
TheDrosophila melanogaster Gartgene encodes three enzymatic activities in the pathway for purinede novosynthesis. Alternative processing of the primary transcript leads to the synthesis of two overlapping polypeptides. The coding sequence for both polypeptides is interrupted by an intron that contains a functional cuticle protein gene encoded on the opposite DNA strand. Here we show that this nested organization also exists at the homologous locus of a distantly related species,Drosophila pseudoobscura. In both species, the intronic cuticle gene is expressed in wandering larvae and in prepupae. Remarkably, there are 24 different highly conserved noncoding segments within the intron containing the cuticle gene. These are found upstream of the transcriptional start, at the 3' end, and even within the single intronic gene intron. Other introns in the purine gene, including the intron at which alternative processing occurs, show no such homologies. It seems likely that at least some of the conserved noncoding regions are involved in specifying the high level developmental expression of the cuticle gene. We discuss the possibility that shared cis-acting regulatory sites might enhance transcription of both genes and help explain their nested arrangement.