The asiA gene of bacteriophage T4 codes for the anti-sigma 70 protein.
AUTOR(ES)
Orsini, G
RESUMO
The anti-sigma 70 factor of bacteriophage T4 is a 10-kDa (10K) protein which inhibits the sigma 70-directed initiation of transcription by Escherichia coli RNA polymerase holoenzyme. We have partially purified the anti-sigma 70 factor and obtained the sequence of a C-terminal peptide of this protein. Using reverse genetics, we have identified, at the end of the lysis gene t and downstream of an as yet unassigned phage T4 early promoter, an open reading frame encoding a 90-amino-acid protein with a predicted molecular weight of 10,590. This protein has been overproduced in a phage T7 expression system and partially purified. It shows a strong inhibitory activity towards sigma 70-directed transcription (by RNA polymerase holoenzyme), whereas it has no significant effect on sigma 70-independent transcription (by RNA polymerase core enzyme). At high ionic strength, this inhibition is fully antagonized by the neutral detergent Triton X-100. Our results corroborate the initial observations on the properties of the phage T4 10K anti-sigma 70 factor, and we therefore propose that the gene which we call asiA, identified in the present study, corresponds to the gene encoding this T4 transcriptional inhibitor.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=196100Documentos Relacionados
- Solution structure and stability of the anti-sigma factor AsiA: Implications for novel functions
- Substitutions in Bacteriophage T4 AsiA and Escherichia coli ς70 That Suppress T4 motA Activation Mutations
- The asiA gene product of bacteriophage T4 is required for middle mode RNA synthesis.
- The asiA Gene Product of Bacteriophage T4 Is Required for Middle Mode RNA Synthesis
- T4 AsiA blocks DNA recognition by remodeling σ70 region 4