Microinjected photoreactivating enzymes from Anacystis and Saccharomyces monomerize dimers in chromatin of human cells

J. C.M. Zwetsloot, W. Vermeulen, J. H.J. Hoeijmakers, A. Yasui, A. M.P. Eker, D. Bootsma

    Research output: Contribution to journalArticlepeer-review

    16 Citations (Scopus)

    Abstract

    Photoreactivating enzymes (PRE) from the yeast Saccharomyces cerevisiae and the cyanobacterium Anacystis nidulans have been injected into the cytoplasm of repair-proficient human fibroblasts in culture. After administration of photoreactivation light, PRE-injected cells displayed a significantly lower level of UV-induced unscheduled DNA synthesis (UDS) than non-injected cells. This indicates that monomerization of the UV-induced pyrimidine dimers in the mammalian chromatin had occurred as a result of photoreactivation by the injected PRE at the expense of repair by the endogenous excision pathway. Purified PRE from yeast is able to reduce UDS to 20-25% of the UDS found in non-injected cells, whereas the in vitro more active PRE from A. nidulans gives a reduction to only 70%. This suggests that the eukaryotic enzyme is more efficient in the removal of pyrimidine dimers from mammalian chromatin than its equivalent purified from the prokaryote A. nidulans.

    Original languageEnglish
    Pages (from-to)71-77
    Number of pages7
    JournalMutation Research DNA Repair Reports
    Volume146
    Issue number1
    DOIs
    Publication statusPublished - 1985 Jul

    ASJC Scopus subject areas

    • Medicine(all)

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