In vivo expression from the RpoS-dependent P1 promoter of the osmotically regulated proU operon in Escherichia coli and Salmonella enterica serovar typhimurium:: Activation by rho and hns mutations and by cold stress

被引:21
作者
Rajkumari, K
Gowrishankar, J
机构
[1] Ctr DNA Fingerprinting & Diagnost, Hyderabad 500076, Andhra Pradesh, India
[2] Ctr Cellular & Mol Biol, Hyderabad 500007, Andhra Pradesh, India
关键词
D O I
10.1128/JB.183.22.6543-6550.2001
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
Unlike the sigma (70)-controlled P2 promoter for the osmotically regulated proU operon of Escherichia coli and Salmonella enterica serovar Typhimurium, the sigma (s)-controlled PI promoter situated further upstream appears not to contribute to expression of the proU structural genes under ordinary growth conditions. For S. enterica proU P1, there is evidence that promoter crypticity is the result of a transcription attenuation phenomenon which is relieved by the deletion of a 22-base C-rich segment in the transcript. In this study, we have sought to identify growth conditions and trans-acting mutations which activate in vivo expression from proU PI. The cryptic S. enterica proU PI promoter was activated, individually and additively, in a rho mutant (which is defective in the transcription termination factor Rho) as well as by growth at 10 degreesC. The E. coli proU PI promoter was also cryptic in constructs that carried 1.2 kb of downstream proU sequence, and in these cases activation of in vivo expression was achieved either by a rho mutation during growth at 10 degreesC or by an hns null mutation (affecting the nucleoid protein H-NS) at 30 degreesC. The rho mutation had no effect at either 10 or 30 degreesC on in vivo expression from two other sigma (s)-controlled promoters tested, those for osmY and csiD. In cells lacking the RNA-binding regulator protein Hfq, induction of E. coli proU P1 at 10 degreesC and by hns mutation at 30 degreesC was still observed, although the hfq mutation was associated with a reduction in the absolute levels of PI expression. Our results suggest that expression from proU PI is modulated both by nucleoid structure and by Rho-mediated transcription attenuation and that this promoter may be physiologically important for proU operon expression during low-temperature growth.
引用
收藏
页码:6543 / 6550
页数:8
相关论文
共 61 条
[1]  
Adams JL, 1999, APPL ENVIRON MICROB, V65, P4285
[2]   MUTATIONAL ANALYSIS OF REPRESSION AND ACTIVATION OF THE TYRP GENE IN ESCHERICHIA-COLI [J].
ANDREWS, AE ;
LAWLEY, B ;
PITTARD, AJ .
JOURNAL OF BACTERIOLOGY, 1991, 173 (16) :5068-5078
[3]   Escherichia coli CspA-family RNA chaperones are transcription antiterminators [J].
Bae, WH ;
Xia, B ;
Inouye, M ;
Severinov, K .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2000, 97 (14) :7784-7789
[4]   AUTOGENOUS REGULATION OF TRANSCRIPTION TERMINATION FACTOR-RHO [J].
BARIK, S ;
BHATTACHARYA, P ;
DAS, A .
JOURNAL OF MOLECULAR BIOLOGY, 1985, 182 (04) :495-508
[5]   ROLE FOR THE HISTONE-LIKE PROTEIN H-NS IN GROWTH PHASE-DEPENDENT AND OSMOTIC REGULATION OF SIGMA(S) AND MANY SIGMA(S)-DEPENDENT GENES IN ESCHERICHIA-COLI [J].
BARTH, M ;
MARSCHALL, C ;
MUFFLER, A ;
FISCHER, D ;
HENGGEARONIS, R .
JOURNAL OF BACTERIOLOGY, 1995, 177 (12) :3455-3464
[6]   Linkage map of Escherichia coli K-12, edition 10: The traditional map [J].
Berlyn, MKB .
MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS, 1998, 62 (03) :814-+
[7]   Combinatorial effects of NusA and NusG on transcription elongation and Rho-dependent termination in Escherichia coli [J].
Burns, CM ;
Richardson, LV ;
Richardson, JP .
JOURNAL OF MOLECULAR BIOLOGY, 1998, 278 (02) :307-316
[8]   NUSG OVEREXPRESSION INHIBITS RHO-DEPENDENT TERMINATION IN ESCHERICHIA-COLI [J].
BUROVA, E ;
GOTTESMAN, ME .
MOLECULAR MICROBIOLOGY, 1995, 17 (04) :633-641
[9]  
Cosquer A, 1999, APPL ENVIRON MICROB, V65, P3304
[10]  
Csonka L.N., 1996, COLI SALMONELLA CELL, V1, P1210