New AUG initiation codons in a long 5′ UTR create four dominant negative alleles of the Drosophila C2H2 zinc-finger gene ovo
New AUG initiation codons in a long 5′ UTR create four dominant negative alleles of the Drosophila C2H2 zinc-finger gene ovo
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DOI：
10.1007/s004270050139
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发表时间：
1998-01-01
影响因子：
2.4
通讯作者：
Oliver, B
中科院分区：
文献类型：
--
作者：
Andrews, J;Levenson, I;Oliver, B
生殖系中活跃的启动子产生OVO-A和OVO-B mRNAs，编码一种可能的转录因子的异构体。这些异构体有一个共同的C2H2锌指结构域，但不同的N-末端包括潜在的效应结构域。三个显性-阴性OVO(D)突变的单点突变导致OVO-B mRNAs新的框内起始密码子和OVO-A蛋白带电区域的氨基酸替换。三条证据表明，主要的活性是由于OVO-B mRNAs中新的起始密码子，而不是OVO-A中的氨基酸取代。首先，我们通过插入一个新的框内Aug来制造第四个OVO(D)等位基因。该OVO(D4)等位基因从OVO-B mRNAs编码几乎全长的OVO-A亚型。其次，在新的AUG下游的OVO(D1)中的工程停止密码子取消了显性的负活动。第三，编码高电荷氨基酸结构域的OVO-A区域的大幅缺失完全挽救了功能丧失的OVO等位基因。这些数据表明，OVO(D)突变导致了OVO-A在女性生殖系中的不适当表达。
Promoters active in the germline produce OVO-A and OVO-B mRNAs encoding isoforms of a putative transcription factor. The isoforms have a common C2H2 zinc-finger domain but different N-termini that include potential effector domains. Single point mutations in three dominant-negative ovo(D) mutations result in new in-frame initiation codons in OVO-B mRNAs and amino acid substitutions within charged regions of OVO-A proteins. Three lines of evidence suggest that the dominant activity is due to the new initiation codons in OVO-B mRNAs and not the amino acid substitutions in OVO-A. First, we made a fourth ovo(D) allele by inserting a new in-frame AUG. This ovo(D4) allele encodes a nearly full-length OVO-A isoform from OVO-B mRNAs. Second, engineered stop codons in ovo(D1) downstream of the new AUG abolished dominant negative activity. Third, a substantial deletion of an OVO-A region encoding a highly charged amino acid domain fully rescued loss-of-function ovo alleles. These data suggest that ovo(D) mutations result in inappropriate expression of OVO-A in the female germline.