Autogenous regulation of Escherichia coli polynucleotide phosphorylase during cold acclimation by transcription termination and antitermination.
Adaptation of Escherichia coli at low temperature implicates a drastic reprogramming of gene expression patterns. Mechanisms operating downstream of transcription initiation, such as control of transcription termination, mRNA stability and translatability, play a major role in controlling gene expression in the cold acclimation phase. It was previously shown that Rho-dependent transcription termination within pnp, the gene encoding polynucleotide phosphorylase (PNPase), was suppressed in pnp nonsense mutants, whereas it was restored by complementation with wild type allele. Using a tRNA gene as a reporter and the strong Rho-dependent transcription terminator t ( imm ) of bacteriophage P4 as a tester, here we show that specific sites in the 5'-untranslated region of pnp mRNA are required for PNPase-sensitive cold-induced suppression of Rho-dependent transcription termination. We suggest that suppression of Rho-dependent transcription termination within pnp and its restoration by PNPase is an autogenous regulatory circuit that modulates pnp expression during cold acclimation.
Marchi
Paolo
P
Dipartimento di Scienze biomolecolari e Biotecnologie, Università degli Studi di Milano, Via Celoria 26, 20133, Milano, Italy.
Longhi
Vera
V
Zangrossi
Sandro
S
Gaetani
Elisa
E
Briani
Federica
F
Dehò
Gianni
G
D020121:5' Untranslated Regions; D000483:Alleles; D001483:Base Sequence; D003080:Cold Temperature; D004926:Escherichia coli / Q000201:enzymology*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000378:metabolism; D011117:Polyribonucleotide Nucleotidyltransferase / Q000096:biosynthesis* / Q000235:genetics; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic; D020741:rho GTP-Binding Proteins / Q000378:metabolism
D020121:5' Untranslated Regions; D012343:RNA, Transfer; D011117:Polyribonucleotide Nucleotidyltransferase; D020741:rho GTP-Binding Proteins