Autogenous regulation of transcription termination factor Rho.
We present evidence that the transcription termination factor Rho is autogenously regulated in Escherichia coli. The steady-state level of Rho is increased approximately tenfold in rho mutant cells. In the rho+ revertants, the content of Rho is similar to the wild-type level. A rho-/rho+ merodiploid produces equimolar amounts of the mutant and the wild-type Rho polypeptides, both at a reduced level compared to the mutant. The steady-state level of rho messenger RNA is also increased in a rho mutant. A rho-galK transcriptional fusion produces at least tenfold more galactokinase in a rho- strain than in a rho+ strain. In vitro, in a coupled transcription-translation system, the synthesis of Rho protein is specifically inhibited by wild-type Rho but not by Rho15 mutant protein. Anti-Rho antibody specifically stimulates Rho synthesis in the rho+ extract but not in a rho- extract. We suggest that the autogenous regulation of Rho involves premature transcription termination within the rho gene. Regulation of Rho level may provide the cell a mechanism to modulate the expression of genes which are separated from their promoters by Rho-dependent termination signals.
Barik
S
S
Bhattacharya
P
P
Das
A
A
D000251:Adenosine Triphosphatases / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005686:Galactokinase / Q000032:analysis; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005809:Genes, Regulator; D009154:Mutation; D009693:Nucleic Acid Hybridization; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012234:Rho Factor / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D001618:beta-Lactamases / Q000096:biosynthesis
D012329:RNA, Bacterial; D012333:RNA, Messenger; D012234:Rho Factor; D014157:Transcription Factors; D005686:Galactokinase; D001618:beta-Lactamases; D000251:Adenosine Triphosphatases; C031715:rho-ATPase