Physical Studies of the Translocatable Genetic Elements in Bacteria

我们将继续分离和表征转录起始后影响转座酶表达的突变，以确定转座酶基因翻译如此罕见的原因，评估翻译和信使降解之间的相互作用，并确定这些事件在IS10反义抑制中的作用。我们将分析缺乏IHF和/或HU的大肠杆菌突变株，以确定这些以及野生型细胞中存在的任何其他相关辅助宿主因子对体内IS10外端活性和宿主因子对转座酶表达抑制的相对贡献。我们还将通过检查不同生长条件下IHF水平的变化，试图了解大肠杆菌使用IHF调节IS10转位（和其他过程）的原因。最后，利用缺乏已知宿主因子的菌株，我们将分离出外端活性恢复的复归物，以期鉴定出其他辅助蛋白的基因。根据(1)和(2)的进展，我们可能会开始寻找在转位反应中有缺陷的大肠杆菌突变体。

We will continue our isolation and characterization of mutations that affect transposase expression at steps subsequent to transcription initiation in order to determine why translation of the transposase gene is so rare, to assess the interplay between translation and messenger degradation, and to determine the roles of these events in IS10 anti-sense inhibition. We will analyze bacterium E.coli mutant strains lacking IHF and/or HU to determine the relative contributions of these, and any other related accessory host factors present in wild type cells, to the activity of IS10 outside ends and to host factor inhibition of transposase expression in vivo. We will also try to understand why E.coli uses IHF to regulate IS10 transposition (and other processes) by examining changes in IHF levels under different growth conditions. Finally, using strains lacking known host factors, we will isolate revertants in which outside end activity is restored in hopes of identifying genes for additional accessory proteins. Depending on the progress made in (1) and (2), we may initiate a new search for E.coli mutants defective in the transposition reaction.