Molecular analysis of the bicoid gene from Drosophila pseudoobscura: identification of conserved domains within coding and noncoding regions of the bicoid mRNA.
Molecular analysis of the bicoid gene from Drosophila pseudoobscura: identification of conserved domains within coding and noncoding regions of the bicoid mRNA.
复制标题
果蝇 bicoid 基因的分子分析：鉴定 bicoid mRNA 编码区和非编码区的保守结构域。
DOI：
10.1002/j.1460-2075.1990.tb07490.x
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Kaufman,TC
中科院分区：
文献类型：
--
作者：
Seeger,MA;Kaufman,TC
果蝇胚胎发生过程中前部位置信息的特化在很大程度上取决于母体效应基因bicoid（bcd）的功能。bcd功能的两个方面尤其引人注目。首先，bcd蛋白产物在早期胚胎发生过程中形成梯度，其以浓度依赖性方式调节至少一个合子分割基因hunchback的转录。其次，bcd蛋白梯度的形成取决于卵子发生过程中bcd mRNA在卵母细胞/胚胎前端的特异性定位，这一过程需要bcd mRNA 3′非翻译区内的顺式作用625个核苷酸序列。我们已经克隆和测序的bcd基因从果蝇pseudobscura作为一种工具，在确定重要的功能结构域在这个转录单位。DNA序列比较显示：（i）在bcd蛋白的拟议功能结构域中氨基酸序列保守程度不同，（ii）bcd mRNA定位元件内潜在RNA二级结构的保守，（iii）在5′端非翻译前导序列内维持一个短的开放阅读框，可能在翻译调控中发挥作用。最后，当通过种系转化将拟暗果蝇bcd基因置于黑腹果蝇基因组中时，该基因部分挽救了bcd-突变的表型。缺乏完整的表型拯救可以部分解释由观察到的不适当的定位D. pseudobscura bcd mRNA表达时，在D. melanogaster。
The specification of anterior positional information during Drosophila embryogenesis is largely dependent upon the function of the maternal‐effect gene bicoid (bcd). Two aspects of bcd function are particularly striking. First, the bcd protein product forms a gradient during early embryogenesis, which regulates the transcription of at least one zygotic segmentation gene, hunchback, in a concentration dependent manner. Secondly, formation of the bcd protein gradient is dependent upon the specific localization of bcd mRNAs at the anterior end of the oocyte/embryo during oogenesis, a process which requires a cis‐acting 625 nucleotide sequence within the 3′ untranslated region of the bcd mRNA. We have cloned and sequenced the bcd gene from Drosophila pseudoobscura as a tool in identifying important functional domains within this transcription unit. DNA sequence comparisons reveal: (i) varying degrees of amino acid sequence conservation among the proposed functional domains of the bcd protein, (ii) the conservation of potential RNA secondary structures within the bcd mRNA localization element, and (iii) the maintenance of a short open reading frame within the 5′ untranslated leader that may play a role in translational regulation. Finally, the D.pseudoobscura bcd gene partially rescues the phenotype of a bcd‐ mutation when placed into the D.melanogaster genome by germline transformation. The lack of full phenotypic rescue can be explained in part by the observed improper localization of the D.pseudoobscura bcd mRNA when expressed in D.melanogaster.