期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：12
页码：6177-6181
DOI：10.1073/pnas.75.12.6177
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A gene affecting the sigma subunit of DNA-dependent RNA polymerase is tightly linked to dnaG at 66 min on the Escherichia coli chromosome. In order to create an easily selectable marker in this region, we inserted transposon-10, which carries a gene determining resistance to tetracycline (tet) near 66 min, and the order tolC-dnaG-sigma-tet was determined. We used frequency of contransduction with tet as a criterion to screen a collection of spontaneous temperature-sensitive Escherichia coli mutants that might affect the sigma subunit. One such mutant was found to map at the sigma locus. The sigma subunit isolated from this mutant is unstable at 46 degrees C in vitro and has an altered electrophoretic mobility. The temperature sensitivity of RNA synthesis in this mutant indicates that most transcription in E. coli is sigma dependent.
