REPAIR OF PSORALEN PLUS NEAR ULTRAVIOLET LIGHT DAMAGE IN BACTERIOPHAGES T3 AND T4 |
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| Authors: | Peter Strike Hâf O Wilbraham Erling Seeberg† |
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| Institution: | *Department of Genetics, University of Liverpool, Liverpool L69 3BX, England;††Division for Toxicology, Norwegian Defence Research Establishment, Kjeller, Norway |
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| Abstract: | Abstract— Repair of T3 and T4 DNA damaged by treatment with 8-methoxypsoralen plus near UV (PNUV) has been investigated. It is shown that the excision repair mechanisms of the host cell can repair a substantial fraction of the psoralen-DNA mono-adducts in T3 DNA, but cannot by themselves repair crosslinks. In contrast neither the excision repair system of the host nor the phage coded v gene endonuclease is involved in the repair of psoralen adducts in T4 DNA. Multiplicity reactivation is effective in the recovery of T4 DNA containing psoralen-DNA mono-adducts, but is ineffective in the recovery of crosslinked phages. Comparisons of the lethality of PNUV treatment and the number of crosslinks induced in T4 DNA show clearly that mono-adducts are lethal to this phage. Both T3 and T4, however, appear to effectively repair many mono-adducts by postreplicational repair. |
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