[Effect of mutations of Escherichia coli K-12 chromosome on the integration of bacteriophage Mu introduced into cells by infection or conjugation]. / Vliianie mutatsii Escherichia coli K-12 na vnedrenie v khromosomu genoma bakteriofaga Mu, vnesennogo v kletki pri infektsii ili kon''iugatsii.

We present the detailed research on the previously described Escherichia coli K-12 Mud- mutants with impaired development of bacteriophage Mu. The ability of Mu phage DNA to penetrate into mutant cells on infection was shown. If introduced into the cells or combined with mud mutation by recombination, the prophage may be induced, which results in phage Mu lythic development and phage burst from mutant cells. In the course of conjugative transfer into the mutant cells, within a DNA fragment of the lysogenic donor chromosome, MupAp1 prophage is not inherited by recombinants. At the same time, Mu prophage deficient in genes A and B, whose products are required for transposition, is inherited by the mutant with the usual frequency. These data enable us to conclude that the mud mutations disturb the stage of conservative transposition which is connected with the insertion of the Mu prophage into the chromosome, after excision from the linear DNA introduced into the cells via infection or conjugation.

[Genetic analysis of the Mud mutants of Escherichia coli K-12 with an impaired ability to maintain bacteriophage Mu development]. / Geneticheskii analiz Mud-mutantov Escherichia coli K-12 s narushennoi sposobnost'iu podderzhivat' razvitie bakteriofaga Mu.

Properties of mud mutations affecting intracellular development of bacteriophage Mu have been studied. We demonstrate pleiotropy of these mutations as well as their effect on the development of Mu-like heteroimmune D108 phage and P1 phage, on the ability to inherit Mu prophage within the chromosome during conjugation, and the abortive inheritance of chromosomal markers during P1 transduction. Experimental evidence is given to support the concept that the effect of the mutations has no relation to the mutants' impaired ability to adsorb the phages. Genetic analysis which involved conjugational crossings using different Hfr donors and F' plasmids made it possible to localize the mud-1 mutation between ilv and metE genes in the region of 84-85 min of the Escherichia coli K-12 genetic map. The nature of mutations and a possible functional role of the mud-impaired gene is discussed.