Systematic mutagenesis of the thymidine tract of the pyrBI attenuator and its effects on intrinsic transcription termination in Escherichia coli.
Systematic mutagenesis of the thymidine tract of the pyrBI attenuator and its effects on intrinsic transcription termination in Escherichia coli.
复制标题
PyrBI 衰减子胸苷束的系统诱变及其对大肠杆菌内源转录终止的影响。
DOI：
10.1111/j.1365-2958.2007.05902.x
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发表时间：
2007
影响因子：
3.6
通讯作者：
TurnboughJr,CharlesL
中科院分区：
文献类型：
--
作者：
Sipos,Katalin;Szigeti,Reka;Dong,Xiuzhu;TurnboughJr,CharlesL
ThepyrBIattenuator ofEscherichia coliis an intrinsic transcription terminator composed of DNA with a hyphenated dyad symmetry and an adjacent 8 bp T:A tract (T‐tract). These elements specify a G+C‐rich terminator hairpin followed by a run of eight uridine residues (U‐tract) in the RNA transcript. In this study, we examined the effects onin vivotranscription termination of systematic base substitutions in the T/U‐tract of thepyrBIattenuator. We found that these substitutions diminished transcription termination efficiency to varying extents, depending on the nature and position of the substitution. In general, substitutions closer to the dyad symmetry/terminator hairpin exhibited the most significant effects. Additionally, we examined the effects onin vivotranscription termination of mutations that insert from 1 to 4 bases between the terminator hairpin and U‐tract specified by thepyrBIattenuator. Our results show an inverse relationship between termination efficiency and the number of bases inserted. The effects of the substitution and insertion mutations on termination efficiency at thepyrBIattenuator were also measuredin vitro, which corroborated thein vivoresults. Our results are discussed in terms of the current models for intrinsic transcription termination and estimating termination efficiencies at intrinsic terminators of other bacteria.
