Previous investigation on the mutagenic effects of 3,N4-Ethenocytosine (εC), a nonpairing DNA lesion,revealed the existence of a novel SOS-independent inducible mutagenic mechanism in E. coli termed UVM for UV modula...Previous investigation on the mutagenic effects of 3,N4-Ethenocytosine (εC), a nonpairing DNA lesion,revealed the existence of a novel SOS-independent inducible mutagenic mechanism in E. coli termed UVM for UV modulation of mutagenesis. To investigate whether UVM is mediated by an alteration of DNA replication, we have set up an in vitro replication system ill which phage M13 viral single-stranded DNA bearing a single site-specific (εC) residue is replicated by soluble protein extracts from E. coli cells. Replication products were analyzed by agarose gel electrophoresis and the frequency of translesion synthesis was determined by restriction endonuclease analyses. Our data indicate that DNA replication is strongly inhibited by εC, but that translesion DNA synthesis does occur in about 14% of the replicated DNA molecules. These results are very similar to those observed previously in vivo, and suggest that this experimental system may be suitable for evaluating alterations in DNA replication in UVM-induced cells.展开更多
Oligodeoxynucleotides (Oligomers) including modified and unmodified, homo-and heterooligomers were tested for their ability to inhibit mouse SRS leukemia virus (SRSV)-induced proliferation of cells, colony formation, ...Oligodeoxynucleotides (Oligomers) including modified and unmodified, homo-and heterooligomers were tested for their ability to inhibit mouse SRS leukemia virus (SRSV)-induced proliferation of cells, colony formation, syncytium formation and reverse transcriptase (RT) activity in vitro. Phosphorothioate analogs complementary to Mo-MuLV sequences, as well as noncomplementary homooligomers, were found to be active. Unmodified homooligomer (dC14) also showed inhibition of growth of ascitic lymphoma carrying SRS virus. Our study suggests that different classes of oligonucleotides may inhibit SRSV replication with different mechanisms.展开更多
文摘Previous investigation on the mutagenic effects of 3,N4-Ethenocytosine (εC), a nonpairing DNA lesion,revealed the existence of a novel SOS-independent inducible mutagenic mechanism in E. coli termed UVM for UV modulation of mutagenesis. To investigate whether UVM is mediated by an alteration of DNA replication, we have set up an in vitro replication system ill which phage M13 viral single-stranded DNA bearing a single site-specific (εC) residue is replicated by soluble protein extracts from E. coli cells. Replication products were analyzed by agarose gel electrophoresis and the frequency of translesion synthesis was determined by restriction endonuclease analyses. Our data indicate that DNA replication is strongly inhibited by εC, but that translesion DNA synthesis does occur in about 14% of the replicated DNA molecules. These results are very similar to those observed previously in vivo, and suggest that this experimental system may be suitable for evaluating alterations in DNA replication in UVM-induced cells.
文摘Oligodeoxynucleotides (Oligomers) including modified and unmodified, homo-and heterooligomers were tested for their ability to inhibit mouse SRS leukemia virus (SRSV)-induced proliferation of cells, colony formation, syncytium formation and reverse transcriptase (RT) activity in vitro. Phosphorothioate analogs complementary to Mo-MuLV sequences, as well as noncomplementary homooligomers, were found to be active. Unmodified homooligomer (dC14) also showed inhibition of growth of ascitic lymphoma carrying SRS virus. Our study suggests that different classes of oligonucleotides may inhibit SRSV replication with different mechanisms.
