Catalytic properties of DNA polymerase alpha activity associated with the heart-stabilized nuclear matrix prepared from HeLa S3 cells.
We have investigated whether or not ATP or other nucleoside di- and trisphosphates (including some nonhydrolysable ATP analogues) can stimulate the activity and/or the processivity of DNA polymerase alpha associated with the nuclear matrix obtained from HeLa S3 cell nuclei that had been stabilized at 37 degrees C prior to subfractionation, as has been reported previously for DNA polymerase alpha bound to the nuclear matrix prepared from 22-h regenerating rat liver. We have found that HeLa cell matrix-associated DNA polymerase alpha activity could not be stimulated at all by ATP or other nucleotides, a behaviour which was shared also by DNA polymerase alpha activity that solubilizes from cells during the isolation of nuclei and that is thought to be a form of the enzyme not actively engaged in DNA replication. Moreover, the processivity of matrix-bound DNA polymerase alpha activity was low (< 10 nucleotides). These results were obtained with the matrix prepared with either 2 M NaCl or 0.25 M (NH4)2SO4 and led us to consider that a 37 degree incubation of isolated nuclei renders resistant to high-salt extraction a form of DNA polymerase alpha which is unlikely to be involved in DNA replication in vivo.
Martelli
A M
AM
Dipartimento di Morfologia Umana Normale, Università degli Studi di Trieste, Italy.
Bareggi
R
R
Narducci
P
P
D000255:Adenosine Triphosphate / Q000494:pharmacology; D002467:Cell Nucleus / Q000201:enzymology*; D004247:DNA / Q000096:biosynthesis*; D004257:DNA Polymerase II / Q000187:drug effects / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D015530:Nuclear Matrix / Q000201:enzymology; D009711:Nucleotides / Q000494:pharmacology; D011089:Polydeoxyribonucleotides / Q000378:metabolism
D009711:Nucleotides; D011089:Polydeoxyribonucleotides; D000255:Adenosine Triphosphate; D004247:DNA; D004257:DNA Polymerase II