Laboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Wita Stwosza 59, 80-308 Gdańsk, Poland.
Laboratory of Molecular Bacteriology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Dębinki 1, 80-211 Gdańsk, Poland.
J Gen Virol. 2013 Apr;94(Pt 4):896-905. doi: 10.1099/vir.0.048686-0. Epub 2012 Dec 12.
Bacteriophage T4 survival in its natural environment requires adjustment of phage development to the slow bacterial growth rate or the initiation of mechanisms of pseudolysogeny or lysis inhibition (LIN). While phage-encoded RI and probably RIII proteins seem to be crucial players in pseudolysogeny and LIN phenomena, the identity of proteins involved in the regulation of T4 development in slowly growing bacteria has remained unknown. In this work, using a chemostat system, we studied the development of wild-type T4 (T4wt) and its rI (T4rI) and rIII (T4rIII) mutants in slowly growing bacteria, where T4 did not initiate LIN or pseudolysogeny. We determined eclipse periods, phage propagation times, latent periods and burst sizes of T4wt, T4rI and T4rIII. We also compared intracellular proteomes of slowly growing Escherichia coli infected with either T4wt or the mutants. Using two-dimensional PAGE analyses we found 18 differentially expressed proteins from lysates of infected cells. Proteins whose amounts were different in cells harbouring T4wt and the mutants are involved in processes of replication, phage-host interactions or they constitute virion components. Our data indicate that functional RI and RIII proteins - apart from their already known roles in LIN and pseudolysogeny - are also necessary for the regulation of phage T4 development in slowly growing bacteria. This regulation may be more complicated than previously anticipated, with many factors influencing T4 development in its natural habitat.
噬菌体 T4 在其自然环境中的生存需要调整噬菌体的发育，以适应细菌缓慢的生长速度，或者启动假溶原或溶原抑制（LIN）机制。虽然噬菌体编码的 RI 和可能的 RIII 蛋白似乎是假溶原和 LIN 现象的关键因素，但参与调节在缓慢生长的细菌中 T4 发育的蛋白质的身份仍然未知。在这项工作中，我们使用恒化器系统研究了野生型 T4（T4wt）及其 rI（T4rI）和 rIII（T4rIII）突变体在缓慢生长的细菌中的发育，在这些细菌中 T4 不会启动 LIN 或假溶原。我们确定了 T4wt、T4rI 和 T4rIII 的潜伏期、噬菌体繁殖时间、潜伏期和爆发大小。我们还比较了感染 T4wt 或突变体的缓慢生长大肠杆菌细胞的细胞内蛋白质组。使用二维 PAGE 分析，我们从感染细胞的裂解物中发现了 18 种差异表达的蛋白质。在携带 T4wt 和突变体的细胞中数量不同的蛋白质参与复制、噬菌体-宿主相互作用过程，或者构成病毒粒子成分。我们的数据表明，功能性 RI 和 RIII 蛋白——除了它们在 LIN 和假溶原中的已知作用外——对于调节在缓慢生长的细菌中 T4 的发育也是必要的。这种调节可能比预期的更复杂，许多因素影响噬菌体 T4 在其自然栖息地的发育。
