Structural and regulatory divergence among site-specific recombination genes of lambdoid phage.
Structural and regulatory divergence among site-specific recombination genes of lambdoid phage.
复制标题
羔羊噬菌体位点特异性重组基因之间的结构和调控差异。
DOI：
10.1016/0022-2836(86)90491-2
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发表时间：
1986
影响因子：
5.6
通讯作者：
Landy,A
中科院分区：
文献类型：
--
作者：
Leong,JM;Nunes-Düby,SE;Oser,AB;Lesser,CF;Youderian,P;Susskind,MM;Landy,A
羔羊噬菌体 φ80 和 P22 具有与 λ 相似的位点特异性重组系统。三种噬菌体均具有不同的插入特异性，但对其附着位点的结构分析表明，三种重组途径具有相似的特征。在本研究中，我们鉴定并测序了 φ80 和 P22 的 intandxis 基因。使用体内质粒重组测定鉴定了 φ80intandxi，并使用 Tn1 插入突变对 P22 基因进行了定位。在所有三种噬菌体中，位点特异性重组基因直接位于噬菌体附着位点附近。有趣的是，φ80int基因的转录方向与λ和P22int相反，导致φ80intandxis的转录趋同。由于其转录方向，φ80int 不能由主要的左向启动子 PL 表达，并且 φ80 整合和切除的调控策略必须与 λ 显着不同。三个系统的重组蛋白的推导氨基酸序列显示出惊人的同源性。与 λ PI 启动子同源的序列比蛋白质编码序列更保守。然而，Int 蛋白在 C 端序列中局部相关，特别是距离 C 端约 50 个残基的一段约 25 个氨基酸残基。 Xis 蛋白可以在其 N 末端对齐。
The lambdoid bacteriophage φ80 and P22 have site-specific recombination systems similar to that of λ. Each of the three phage has a different insertion specificity, but structural analysis of their attachment sites suggests that the three recombination pathways share similar features. In this study, we have identified and sequenced theintandxisgenes of φ80 and P22. φ80intandxiswere identified using a plasmid recombination assayin vivo, and the P22 genes were mapped using Tn1 insertion mutations. In all three phage, the sitespecific recombination genes are located directly adjacent to the phage attachment site. Interestingly, the transcriptional orientation of the φ80intgene is opposite to that of λ and P22int, resulting in convergent transcription of φ80intandxis. Because of its transcriptional orientation, φ80intcannot be expressed by the major leftward promoter, PL, and the regulatory strategy of φ80 integration and excision must differ significantly from that of λ. The deduced amino acid sequences of the recombination proteins of the three systems show surprisingly little homology. Sequences homologous to the λ PIpromoter are more conserved than the protein-coding sequences. Nevertheless, the Int proteins are locally related in the C-terminal sequences, particularly for a stretch of some 25 amino acid residues that lie approximately 50 residues from the C terminus. The Xis proteins can be aligned at their N termini.