Widespread distribution of a group I intron and its three deletion derivatives in the lysin gene of Streptococcus thermophilus bacteriophages
Widespread distribution of a group I intron and its three deletion derivatives in the lysin gene of Streptococcus thermophilus bacteriophages
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DOI：
10.1128/jvi.74.2.611-618.2000
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发表时间：
2000-01-01
影响因子：
5.4
通讯作者：
Brüssow, H
中科院分区：
文献类型：
--
作者：
Foley, S;Bruttin, A;Brüssow, H
从不同生态环境中分离的62株嗜热链球菌噬菌体中，有一半含有一个lysin基因，该基因被一组IA 2内含子中断，噬菌体mRNA剪接被证实。5个突变体的内含子都是由位于内含子开放阅读框（orf 253）的3个不同的缺失事件引起的。预测的orf 253基因序列显示出比周围内含子和溶素基因序列显著更低的GC含量，并且预测的蛋白质与革兰氏阳性和革兰氏阴性细菌的内含子中发现的内切核酸酶共享基序。噬菌体溶素基因的比较揭示了含内含子和无内含子等位基因之间的明确分工，导致建立了与内含子拥有相关的14 bp的一致序列。在噬菌体或嗜热链球菌细菌基因组的其他地方没有发现保守的内含子。内含子RNA的折叠揭示了与其他噬菌体内含子共有的二级结构元件：首先，在P3和P4区域之间的38-bp插入，可以折叠成两个茎环结构（与芽孢杆菌噬菌体SPO 1和亲属的内含子共享）;第二，保守的P7.2区域（与所有噬菌体内含子共享）;第三，P8茎中来自orf 253的终止密码子的位置（与大肠杆菌噬菌体T4和芽孢杆菌噬菌体SPO 1内含子共享）;第四，orf 253，其与在来自乳球菌属，乳杆菌属，和芽孢杆菌（Bacillus）。
Of 62 Streptococcus thermophilus bacteriophages isolated from various ecological settings, half contain a lysin gene interrupted by a group IA2 intron, Phage mRNA splicing was demonstrated. Five phages possess a variant form of the intron resulting from three distinct deletion events located in the intron-harbored open reading frame (orf 253), The predicted orf 253 gene sequence showed a significantly lower GC content than the surrounding intron and lysin gene sequences, and the predicted protein shared a motif with endonucleases found in phages from both gram-positive and gram-negative bacteria. A comparison of the phage lysin genes revealed a dear division between intron-containing and intron-free alleles, leading to the establishment of a 14-bp consensus sequence associated with intron possession. The conserved intron was not found elsewhere in the phage or S, thermophilus bacterial genomes. Folding of the intron RNA revealed secondary structure elements shared with other phage introns: first, a 38-bp insertion between regions P3 and P4 that can be folded into two stem-loop structures (shared with introns from Bacillus phage SPO1 and relatives); second, a conserved P7.2 region (shared with all phage introns); third, the location of the stop codon from orf 253 in the P8 stem (shared with coliphage T4 and Bacillus phage SPO1 introns); fourth, orf 253, which has sequence similarity with the H-N-H motif of putative endonuclease genes found in introns from Lactococcus, Lactobacillus, and Bacillus phages.