title: Two classes of Mu lig mutants: the thermosensitives for integration and replication and the hyperproducers for ligase.
abstract: We have previously shown that Mu restores an active DNA replication at non-permissive temperature in E. coli K12 ligts7 strains. In this paper we describe two new types of phage mutants for the Mu lig function. The Mu ligts mutants are conditional lethals defective for both integration and replication of DNA, unable to 'complement' the bacterial lig mutation; the map between B and lys. The mutants of the other type, on the other hand, are able to restore to a maximum level the activity impaired by the ligts7 mutation in the host. We suggest the hypothesis that the product of Mu lig gene could be part of a complex as a topoisomerase.
mesh_terms: D002872:Chromosome Deletion; D002874:Chromosome Mapping; D011088:DNA Ligases / Q000235:genetics*; D004261:DNA Replication; D004926:Escherichia coli / Q000235:genetics; D008242:Lysogeny; D008954:Models, Biological; D009154:Mutation; D011118:Polynucleotide Ligases / Q000235:genetics*; D012317:RNA Phages / Q000235:genetics*; D013696:Temperature; D014779:Virus Replication
chemical_list: D011088:DNA Ligases; D011118:Polynucleotide Ligases