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Transactivation of several genes of two native Serratia prophages after superinfection by phage kappa
Author(s) -
Steiger H.,
Garbe T.,
Güleke R.,
Gencic Simonida
Publication year - 1987
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620270108
Subject(s) - prophage , lysogenic cycle , biology , gene , mutant , genetics , bacteriophage , dna , genome , circular bacterial chromosome , microbiology and biotechnology , escherichia coli
Serratia marcescens HY bacteria must be lysogenic with either prophage y or ψ to make it possible for phage χ to form plaques unless they carry a so‐called ink mutation. Genes in y and ψ termed any and anp were identified that after infection of ink + cells are necessary for an effective propagation of these phages as well as of coinfecting χ phage. When χ infects y and/or ψ‐Iysogenic cells it transactivates the respective prophage genes by means of two early genes termed tay and tap. It appears that on infection of nonlysogenic ink + cells χ damps its own development, provided the regulatory region of the responsible gene is undermethylated. After χ infection duly to achieve the special methylation of this region seems to be the function of any and anp. There are some more genes in y and ψ prophage under the control of tay and tap , concerning in both cases a Dam methylation (recognition sequence GATC) of χ DNA, a recombination proneness under restricting conditions of χ DNA not modified by the modification enzyme of HY , and the χ plaque size. By hybridization studies a region of homology common to y and ψ was demonstrated which from its size might comprise all the transactivated genes. The view is supported by genetic data indicating an affinity among the any and anp genes. Investigation of various any mutants were indicative of DNA inversions in this region of the y genome. Surprisingly some of the any mutants had become sensitive in their plaque forming ability to an inhibitory activity exerted by prophage ψ. Mutants of ψ unable to interfere but still able to lysogenize were isolated. A model is presented accounting for the formation of pleiotropic and nonpleiotropic mutations with Any phenotype and their reversion types. Possible functions of the y genes and their counterparts in ψ are discussed.