Evolution of T4-related phages
Evolution of T4-related phages
复制标题
DOI：
10.1007/bf01728666
复制
发表时间：
1995-02-01
期刊：
影响因子：
1.6
通讯作者：
Mesyanzhinov, V
中科院分区：
文献类型：
--
作者：
Kutter, E;Gachechiladze, K;Mesyanzhinov, V
在过去的50年里，人们对T-偶噬菌体生物学的认识取得了很大进展。我们现在知道了T4的整个序列，编码近300个基因，其中只有69个在标准实验室条件下被证明是必需的;大约140个基因的特定功能还不清楚。大多数噬菌体基因的起源尚不清楚，T4中只有42个基因与目前GenBank中包含的任何基因具有显著的相似性。相关基因的比较分析现在被用来深入了解这些噬菌体基因的进化起源和相互关系，以及它们的蛋白质产物的功能。从第比利斯医院、长岛污水处理厂、丹佛动物园和哈巴罗夫斯克分离的沙门氏菌的基因组显示出基本的相似性。然而，这些基因组在许多区域相对于彼此显示出大量的插入和缺失，并且对特定序列的更仔细的研究通常揭示出更复杂的关系。只有少数T4相关的基因突变是通过DNA复制进化的。这些包括基因12、34和37的纤维状产物;头蛋白gp 23和gp 24;以及Alt酶及其下游邻居。T4还含有13种明显的I组和II组内含子归巢核酸内切酶的亲戚。各种T偶联蛋白的尾纤维的远端部分含有与其他DNA大肠杆菌的尾纤维区域密切相关的片段，例如Mu，P1，P2和lambda。水平基因转移显然出现在进化的一个主要因素，至少在尾纤维区域，位点特异性重组可能参与主机范围决定因素的交换。
Much progress has been made in understanding T-even phage biology in the last 50 years. We now know the entire sequence of T4, encoding nearly 300 genes, only 69 of which have been shown to be essential under standard laboratory conditions; no specific function is yet known for about 140 of them. The origin of most phage genes is unclear, and only 42 genes in T4 have significant similarity to anything currently included in GenBank. Comparative analysis of related phages is now being used to gain insight into both the evolutionary origins and interrelationships of these phage genes, and the functions of their protein products. The genomes of phages isolated from Tbilisi hospitals, Long Island sewage plants, the Denver zoo, and Khabarovsk show basic similarity. However, these phages show substantial insertions and deletions in a number of regions relative to each other, and closer investigation of specific sequences often reveals much more complex relationships. There are only a few cases in T4-related phages in which there is evidence for evolution through DNA duplication. These include the fibrous products of genes 12, 34, and 37; head proteins gp23 and gp24; and the Alt enzyme and its downstream neighbors. T4 also contains 13 apparent relatives of group I and group II intron homing endonucleases. Distal portions of the tail fibers of various T-even phages contain segments closely related to tail-fiber regions of other DNA coliphages, such as Mu, P1, P2, and lambda. Horizontal gene transfer clearly emerges as a major factor in the evolution of at least the tail-fiber regions, where site-specific recombination probably is involved in the exchange of host-range determinants.