Why do bacteriophage encode tRNAs?

本项目研究噬菌体-细菌相互作用系统，围绕噬菌体tRNA的使用和进化选择。它主要集中在理解为什么噬菌体编码tRNA，以及tRNA如何影响噬菌体宿主范围和噬菌体毒力。进一步的研究路线将包括检查是否有证据表明细菌宿主和噬菌体的共同进化，关于宿主和噬菌体基因组中观察到的tRNA差异。研究的另一个途径将是检验噬菌体tRNA和细菌密码子是否编码相同或不同的tRNA，如果是，是哪些tRNA。coli和T4噬菌体。将产生T4突变体，其具有T4内编码的每种tRNA被系统地敲除，并且将这些突变体的毒力和宿主范围与T4“野生型”噬菌体的毒力和宿主范围进行比较。同时，该项目将进行生物信息学和生物统计学研究，以调查已知和测序的噬菌体及其宿主中tRNA的差异和使用差异。这将涉及比较全基因组分析所建议的噬菌体的系统发育进化与编码的tRNA所建议的噬菌体的预测进化。将基于编码的tRNA的进化与由其细菌宿主编码的tRNA进行比较，将有助于了解细菌tRNA是否被噬菌体定期和随机地获得，它们是否在来自历史宿主的噬菌体基因组中高度保守，或者噬菌体基因组中tRNA的变化是否可能是由于随机突变但仍处于选择性进化压力下。

This project examines bacteriophage-bacterial interaction systems, surrounding the use of and evolutionary selection for bacteriophage tRNAs. It primarily focuses understanding why bacteriophage encode for tRNAs, and how tRNAs impact bacteriophage host range and bacteriophage virulence. Further routes of investigation will include examining if there is evidence of co-evolution of bacterial hosts and bacteriophage, with respect to observed differences in tRNAs in the host and bacteriophage genomes. Another route of investigation will be to examine if bacteriophage tRNAs and bacterial codons are coding for the same or different tRNAs, and if so, which ones.This project will aim to create a model system using E. coli and T4 bacteriophage. T4 mutants will be created which have each tRNA encoded within T4 systematically knocked out, and these mutants' virulence and host range will be compared against the T4 "wild type" bacteriophage's virulence and host range. Concurrently, this project will undertake bioinformatics and biostatistics research to investigate differences and usage differences in tRNAs within known and sequenced bacteriophage and their hosts. This will involve comparing the phylogenetic evolution of bacteriophage as suggested by whole-genome analysis with the predicted evolution of bacteriophage as suggested by encoded tRNAs. Comparing the evolution based on encoded tRNAs against the tRNAs as encoded by their bacterial hosts will offer insight into whether bacterial tRNAs are regularly and randomly acquired by bacteriophage, if they are highly conserved within bacteriophage genomes from a historic host, or if changes in tRNAs in bacteriophage genomes may be due to random mutation but still under selective evolutionary pressures.