MUTATIONAL ANALYSIS OF INTEGRASE ARM-TYPE BINDING-SITES OF BACTERIOPHAGE-LAMBDA - INTEGRATION AND EXCISION INVOLVE DISTINCT INTERACTIONS OF INTEGRASE WITH ARM-TYPE SITES

[摘要] Integrative recombination between specific attachment (att) regions of the bacteriophage lambda genome (attP) and the Escherichia coli genome (attB) results in a prophage flanked by the hybrid recombinant sites attL and attR. Each att site contains sequences to which proteins involved in recombination bind. Using site-directed mutagenesis, we have constructed a related set of point mutations within each of the five Int arm-type binding sites located within attP, attL and attR. Footprint analyses of binding demonstrate that mutating the arm-type sites significantly disrupts the binding of Int. Recombination analyses of mutant att sites in vivo and in vitro demonstrate that only three wild-type arm-type sites within attP are required for efficient integrative recombination. Similar analyses demonstrate that efficient excision can occur with two other different sets of wild-type arm-type sites in attL and attB. These results demonstrate that integrative and excisive recombination may involve interactions of Int with distinct and different subsets of arm-type sites.

[发布日期] 1986-12-05