Phage P4 int gene encodes the integrase responsible for phage integration into and excision from the Escherichia coli chromosome. Here, the data showing that P4 int expression is regulated in a complex manner at different levels are presented. First of all, the Pint promoter is regulated negatively by both Int and Vis, the P4 excisionase. The N-terminal portion of Int appears to be sufficient for such a negative autoregulation, suggesting that the Int N terminus is implicated in DNA binding. Second, full-length transcripts covering the entire int gene could be detected only upon P4 infection, whereas in P4 lysogens only short 59-end covering transcripts were detectable. On the other hand, transcripts covering the 59-end of int were also very abundant upon infection. It thus appears that premature transcription termination and/or mRNA degradation play a role in Int-negative regulation both on the basal prophage transcription and upon infection. Finally,comparison between Pint–lacZ transcriptional and translational fusions suggests that Vis regulates Int expression post-transcriptionally. The findings that Vis is also an RNA-binding protein and that Int may be translated from two different start codons have implications on possible regulation models of Int expression.
Titolo: | Expression of phage P4 integrase is negatively regulated by both Int and Vis |
Autori: | |
Settore Scientifico Disciplinare: | Settore BIO/18 - Genetica |
Data di pubblicazione: | 2006 |
Rivista: | |
Tipologia: | Article (author) |
Digital Object Identifier (DOI): | 10.1099/vir.0.81875-0 |
Appare nelle tipologie: | 01 - Articolo su periodico |