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Regulation and expression of the bacteriophage Mu mom gene: mapping of the transactivation (Dad) function to the C region

1985; Elsevier BV; Volume: 39; Issue: 1 Linguagem: Inglês

10.1016/0378-1119(85)90109-x

1879-0038

Stanley Hattman, Janet Ives, William Margolin, Martha M. Howe,

RNA and protein synthesis mechanisms

Expression of the bacteriophage Mu mom gene is under tight regulatory control. One of the factors required for mom gene expression is the (trans-acting function (designated Dad) provided by another Mu gene. To facilitate studies on the signals mediating mom regulation, we have constructed a mom-lacZ fusion plasmid which synthesizes β-galactosidase only when the Mu Dad transactivating function is provided. λpMu phages carrying different segments of the Mu genome have been assayed for their ability to transactivate β-galactosidase expression by the fusion plasmid. The results of these analyses indicated that the Dad transactivation function is encoded between the leftmost EcoRI site and the lys gene of Mu; this region includes the C gene, which is required for expression of all Mu late genes. Cloning of an approx. 800-bp fragment containing the C gene produced a plasmid which could complement MuC− phages for growth and could transactivate the mom-lacZ fusion plasmid to produce β-galactosidase. These results suggest that the C gene product mediates the Dad transactivation function.