Expression of a DNA replication gene cluster in bacteriophage T4: genetic linkage and the control of gene product interactions.
Expression of a DNA replication gene cluster in bacteriophage T4: genetic linkage and the control of gene product interactions.
复制标题
DNA 复制基因簇在噬菌体 T4 中的表达：遗传连锁和基因产物相互作用的控制。
DOI：
10.1093/genetics/107.4.537
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发表时间：
1984
期刊：
影响因子：
3.3
通讯作者：
Karam,JD
中科院分区：
文献类型：
--
作者：
Gerald,WL;Karam,JD
本研究的结果关系到遗传连锁和控制之间的相互作用的蛋白质产物的不同顺反子。在T4噬菌体中，基因45和44编码噬菌体DNA复制多蛋白复合物的基本组分。T4基因45直接定位在基因44的上游，相对于噬菌体染色体这一区域的阅读的总体方向，但不知道这两个基因是否共转录。已经表明，T4基因45的无义损伤对基因44的错义突变体的生长产生了无义显性抑制作用，但对携带野生型基因44等位基因的噬菌体的生长没有抑制作用。在以前的工作中，我们证实了这些关于基因45突变极性的观察结果，但没有发现这种损伤对突变型或野生型基因44蛋白合成的极性影响。在本研究中，我们证明，基因44蛋白的mRNA是可分离的凝胶电泳从基因45蛋白编码的mRNA。也就是说，这两种蛋白质不是由一个多顺反子信息合成的，并且基因45突变对基因44功能的顺显性抑制作用可能在翻译后阶段表达。我们认为，紧密的遗传连锁，无论是否为某些功能相关顺反子簇提供共享的转录和翻译调节信号，都可能决定这些簇编码的蛋白质合成的细胞内区室化。在原核生物中，这种依赖连接的区室化可以最小化在低水平合成的基因产物之间的扩散距离，并且注定要相互作用。
The results of this study bear on the relationship between genetic linkage and control of interactions between the protein products of different cistrons. In T4 bacteriophage, genes45and44encode essential components of the phage DNA replication multiprotein complex. T4 gene45maps directly upstream of gene44relative to the overall direction of reading of this region of the phage chromosome, but it is not known whether these two genes are cotranscribed. It has been shown that a nonsense lesion of T4 gene45exerts acis-dominant inhibitory effect on growth of a missense mutant of gene44but not on growth of phage carrying the wild-type gene44allele. In previous work, we confirmed these observations on polarity of the gene45mutation but detected no polar effects by this lesion onsynthesisof either mutant or wild-type gene44protein. In the present study, we demonstrate that mRNA for gene44protein is separable by gel electrophoresis from gene45-protein-encoding mRNA. That is, the two proteins are not synthesized from one polycistronic message, and thecis-dominant inhibitory effect of the gene45mutation on gene44function is probably expressed at a posttranslational stage. We propose that close genetic linkage, whether or not it provides shared transcriptional and translational regulatory signals for certain clusters of functionally related cistrons, may determine the intracellular compartmentalization for synthesis of proteins encoded by these clusters. In prokaryotes, such linkage-dependent compartmentation may minimize the diffusion distances between gene products that are synthesized at low levels and are destined to interact.