INT-H - AN INT MUTATION OF PHAGE-LAMBDA THAT ENHANCES SITE-SPECIFIC RECOMBINATION
INT-H - AN INT MUTATION OF PHAGE-LAMBDA THAT ENHANCES SITE-SPECIFIC RECOMBINATION
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DOI：
10.1016/0092-8674(80)90318-9
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发表时间：
1980-01-01
期刊：
影响因子：
64.5
通讯作者：
FRIEDMAN, DI
中科院分区：
文献类型：
--
作者：
MILLER, HI;MOZOLA, MA;FRIEDMAN, DI
The mutation int-h3 maps in the int gene of coliphage .lambda. and results in the synthesis of an integrase with enhanced activity; this result is manifested by an ability to support .lambda. site-specific recombination relatively efficiently, under conditions where the wild-type integrase functions inefficiently. The level of site-specific recombination seen in the presence of the int+ integrase in himA- hosts is greatly reduced, as measured by lysogen formation, intramolecular site-specific integration and excision, and excision of a cryptic .lambda. prophage. In contrast, the int-h3 integrase shows relatively high levels of activities under these conditions. Int-h3 is also more active in other host mutants (himB and hip) that reduce .lambda. site-specific recombination. In the absence of the normal attB site, the frequency of lysogen formation (at secondary sites) by .lambda. int+ is reduced 200-fold. Although .lambda. int-h3 will integrate preferentially at the attB site if it is present, the mutant phage forms lysogens at a high frequency in attB-deleted hosts. .lambda. int-h3 requires himA function for integration at secondary sites. The fact that the int-h3 integrase uses the same att sites and the same host functions as the int+ integrase suggests that the mutation results in a quantitative, rather than a qualitative change in integrase activity; that is, the int-h3 integrase is more active. The mutant integrase supports site-specific recombination with att sites that carry the att24 mutation. The int-h3 integrase is apparently endowed with an enhanced ability to recognize att sequences, including some that are not effectively recognized by wild-type integrase.
