Bacteriophage P4 Vis protein is needed for prophage excision
| Autor: | Gianni Dehò, Ian B. Dodd, Daniela Piazzolla, Francesca Forti, Simona Calı̀, Daniela Ghisotti, E. Spoldi |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
viruses
Mutant Molecular Sequence Data Coliphages Frameshift mutation Bacteriophage Viral Proteins Plasmid Bacteriophage P4 Virology Consensus Sequence Amino Acid Sequence Cloning Molecular DNA binding Promoter Regions Genetic Gene Prophage Genetics Lysogenization DNA bending biology Base Sequence Integrases Circular bacterial chromosome technology industry and agriculture biochemical phenomena metabolism and nutrition biology.organism_classification Molecular biology humanities Vis regulator DNA-Binding Proteins Settore BIO/18 - Genetica Attachment Sites Microbiological DNA Viral Ectopic expression Virus Activation |
| Zdroj: | Virology. (1):82-92 |
| ISSN: | 0042-6822 |
| DOI: | 10.1016/j.virol.2004.01.016 |
| Popis: | Upon infection of its host Escherichia coli, satellite bacteriophage P4 can integrate its genome into the bacterial chromosome by Int-mediated site-specific recombination between the attP and the attB sites. The opposite event, excision, may either occur spontaneously or be induced by a superinfecting P2 helper phage. In this work, we demonstrate that the product of the P4 vis gene, a regulator of the P4 late promoters PLL and Psid, is needed for prophage excision. This conclusion is supported by the following evidence: (i) P4 mutants carrying either a frameshift mutation or a deletion of the vis gene were unable to excise both spontaneously or upon P2 phage superinfection; (ii) expression of the Vis protein from a plasmid induced P4 prophage excision; (iii) excision depended on a functional integrase (Int) protein, thus suggesting that Vis is involved in the formation of the excision complex, rather than in the excision recombination event per se; (iv) Vis protein bound P4 DNA in the attP region at two distinct boxes (Box I and Box II), located between the int gene and the attP core region, and caused bending of the bound DNA. Furthermore, we mapped by primer extension the 5′ end of the int transcript and found that ectopic expression of Vis reduced its signal intensity, suggesting that Vis is also involved in negative regulation of the int promoter. |
| Databáze: | OpenAIRE |
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