GENOMIC POLYMORPHISM IN THE T-EVEN BACTERIOPHAGES
GENOMIC POLYMORPHISM IN THE T-EVEN BACTERIOPHAGES
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DOI：
10.1002/j.1460-2075.1994.tb06736.x
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发表时间：
1994-09-01
期刊：
影响因子：
11.4
通讯作者：
KRISCH, HM
中科院分区：
文献类型：
--
作者：
REPOILA, F;TETART, F;KRISCH, HM
我们比较了与T4相关的49种噬菌体的基因组。六个染色体区域的PCR分析揭示了两种类型的局部序列变异。在四个基因座中，我们发现所有基因组中只有两种可供选择的构型可以被分析。相比之下，两个高度多态性的基因座在存在的序列的数量、顺序和同一性方面表现出变化。在噬菌体T4中，这两个高度多态性的基因座编码内部蛋白（IP），其在噬菌体颗粒中被包裹并注入病毒DNA。在各种T4相关的转录因子中，IP基因座上已鉴定出10个不同的ORF，其氨基酸序列具有内部蛋白的特征。在这些编码序列中的每一个的开始是高度保守的11个氨基酸前导基序。此外，在大多数这些ORF的5'和3'端，存在类似于70bp的序列，其包含具有重叠反向重复序列的T4早期启动子序列。这些侧翼序列内的同源性可以介导基因座内IP序列的重组改组。提出了新的IP样序列在确定噬菌体宿主范围中的作用，因为之前已经在T4的IP 1基因中证明了这种作用。
We have compared the genomes of 49 bacteriophages related to T4. PCR analysis of six chromosomal regions reveals two types of local sequence variation. In four loci, we found only two alternative configurations in all the genomes that could be analyzed. In contrast, two highly polymorphic loci exhibit variations in the number, the order and the identity of the sequences present. In phage T4, both highly polymorphic loci encode internal proteins (IPs) that are encapsidated in the phage particle and injected with the viral DNA. Among the various T4-related phages, 10 different ORFs have been identified in the IP loci; their amino acid sequences have the characteristics of internal proteins. At the beginning of each of these coding sequences is a highly conserved 11 amino acid leader motif. In addition, both 5' and 3' to most of these ORFs, there is a similar to 70 bp sequence that contains a T4 early promoter sequence with an overlapping inversely repeated sequence. The homologies within these flanking sequences may mediate the recombinational shuffling of the IP sequences within the locus. A role for the new IP-like sequences in determining the phage host range is proposed since such a role has been previously demonstrated for the IP1 gene of T4.