Search PubMed⌕ Search

Biomedical subjects

W G Verly

Publications and source records attributed to W G Verly.

104 records · Page 6Linked to original sources
PubMedDate not supplied

Repair of AP sites in DNA.

Escherichia coli endonuclease VI is a deoxyribonuclease specific for AP (apurinic or apyrimidinic) sites; it cleaves the phosphodiester bond immediately neighbouring the AP site on its 5' side leaving 3'-hydroxyl and 5'-phosphate ends. DNA with AP sites can be repaired in vitro with endonuclease VI, DNA polymerase I and ligase; the repair mechanism is described. E. coli has other AP endonucleases; some of them are not specific for AP sites and some of them cut 3' to the AP sites. Most of the rat liver AP endonuclease activity is in chromatin. Some is however found in other cell compartments and it has been speculated that these enzymes might be precursors of the chromatin enzyme. The chromatin AP endonuclease is specific for AP sites; it cuts 5' to the AP site. DNA with AP sites can be repaired in vitro with enzymes purified from chromatin; AP endonuclease, 5'-3 exonuclease, DNA polymerase beta and ligase.

Apurinic Acid↗
PubMedDate not supplied

Repair of O6-alkylguanine lesions in DNA by chromatin enzymes.

Disappearance of 7-ethylguanine and O6-ethylguanine lesions from nuclear DNA is observed on incubation of isolated rat liver nuclei previously treated with ethylnitrosourea. Free 7-ethylguanine but no free O6-ethylguanine is released in the medium. Incubation of methylated or ethylated DNA with chromatin proteins leads to the disappearance of O6-methylguanine or O6-ethylguanine from DNA; the methyl group or the ethyl group is transferred to proteins where it is accepted by cystein residues. Repair of O6-methylguanine and repair of O6-ethylguanine lesions in DNA consume a common reactant which is likely the acceptor protein. The repair does not seem however to be a simple bimolecular reaction between the O6-alkylguanine and the cystein of the acceptor protein.

Alkylation↗