DNA single stranded gaps formed during DNA repair synthesis induced by methyl methanesulfonate are filled by sequential action of aphidicolin- and dideoxythymidine sensitive DNA polymerases in HeLa cells

Abstract

DNA repair synthesis induced by methyl methanesulfonate in preconditioned HeLa cells in which DNA replicative synthesis had been highly suppressed was inhibited by aphidicolin (an inhibitor of DNA polymerases alpha and delta) and dideoxythymidine (ddThR, an inhibitor of DNA polymerase beta). Incomplete repair patches sensitive to exonuclease III were accumulated in the presence of aphidicolin while not in the presence of ddThR. These patches were comopleted by the combined action of Klenow fragment and T4 DNA ligase, indicating that the single-stranded gaps were formed during the repair synthesis. Moreover, ddThR had little effect on the repair synthesis in the presence of aphidicolin. Thus, the results suggest that the single-stranded gaps may be sealed first by aphidicolin-sensitive polymerase followed by ddThR-sensitive DNA polymerase on the same site of the repair patch.

DNA synthesis in osmoprimed leek (Allium porrumL.) seeds and evidence for repair and replication

“…replication, processes known to be insensitive to the presence of aphidicolin (Spadari et al, 1982), or possibly a contribution from nuclear DNA repair synthesis, although it should also be noted that DNA polymerase a-like enzyme activity has been implicated in DNA repair synthesis in HeLa cells (Park et al, 1991). When leek seeds are germinated without an osmopriming treatment, DNA synthesis is insensitive to aphidicolin for up to at least 4 days (Fig.…”

Function of DNA synthesis and DNA repair in the survival of embryos during early germination and in dormancy

“…These rates are initially similar to those that take place in ND embryos, but at the stage when the first S-phase occurs in untreated ND embryos, ABA-treated embryos and D embryos diverge metabolically from the untreated ND controls. The polymerase involved could be P but based on inhibitor studies with HeLa cells (Park et al, 1991) could also include a and 8 functions. The ABA-insensitive DNA synthesis (Table 6a), observed early in imbibition (after 0-3 h) is likely, therefore, to be dependent primarily upon functionally active pre-formed enzymes stored within the dry embryo.…”

“…The aphidicolin and ddTTP results indicate that this includes a polymerase activity associated with DNA repair. The polymerase involved could be P but based on inhibitor studies with HeLa cells (Park et al, 1991) could also include a and 8 functions. At later times (by 24 h) DNA synthesis corresponds with the presence (and the synthesis) of new proteins, of which a and 8 typepolymerases appear (from inhibitor results) to be a major component in both ND and D embryos.…”

Mouse models to explore the biological and organismic role of DNA polymerase beta

“…Many additional studies supported this "DNA repair" role for Polβ in response to different DNA damaging agents, including methyl methane sulfonate (Park et al 1991), uracil (Dianov et al 1992;Singhal and Wilson 1993;Singhal et al 1995;Nealon et al 1996), UV-radiation (Orlando et al 1988), G-T mis-pairs (Wiebauer and Jiricny 1990), benzo[a]pyrene (Otsuka et al 1987), ionizing radiation (Price 1993), and bleomycin (Seki and Oda 1986;Digiuseppe and Dresler 1989). In addition, several groups reported complete BER activity in vitrowith purified Polβ and purified BER proteins (Singhal et al 1995;Kubota et al 1996;Nealon et al 1996).…”