Reversal of Mu gem2ts-induced mutations |
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Authors: | P Ghelardini JC Liébart G Fabozzi B Tomassini R D'Ari L Paolozzi |
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Institution: | Centro di Studio per gli Acidi Nucleici del CNR, c/o Dipartimento di Genetica e Biologia Molecolare, Universitàdi Roma «La Sapienza', Piazzale A. Moro 5, 00185 Rome, Italy;Institut Jacques Monod, CNRS, UniversitéParis 7, Paris, France;Dipartimento di Biologia, Università'Tor Vergata', Rome, Italy |
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Abstract: | Abstract: Mutations induced by the integration of a Mu gem 2ts mutant prophage can revert at frequencies around 1 × 10−6, more than 104-fold higher than that obtained with Mu wild-type. Several aspects characterize Mu gem 2ts precise excision: (i) the phage transposase is not involved; (ii) the RecA protein is not necessary; and (iii) revertants remain lysogenic with the prophage inserted elsewhere in the host genome. In addition, prophage re-integration seems to be non-randomly distributed, whereas Mu insertion into the host genome is a transposition event without any sequence specificity. In this paper, we describe that the site of re-integration somehow depends on the original site of insertion. Two alternative models are proposed to explain the strong correlation between donor and receptor sites. |
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Keywords: | Bacteriophage Mu Precise excision Transposition |
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