title: On the association of DNA polymerase alpha activity with the nuclear matrix in HeLa cells.
abstract: The association of DNA polymerase alpha activity with the nuclear matrix has been reinvestigated in HeLa cells. Isolated nuclei were extracted with 2M NaCl and then digested with Dnase I and the final structures were recovered by centrifugation through a sucrose cushion. Typically over 98% of the total DNA synthesized in the matrix fraction on either endogenous matrix-associated DNA or activated calf thymus DNA was due to DNA polymerase alpha as defined by inhibition to n-ethylmaleimide or aphidicolin. DNA polymerase beta activity was absent or recovered in only trace amounts. Matrix-bound DNA polymerase alpha activity demonstrated a remarkable degree of stability: DNA synthesis was essentially linear up to 3 hours at 37 degrees C. Overall, these results substantiate previous findings from regenerating rat liver, unlike other data obtained from tissue culture cells.
authors.affiliation: Istituto di Anatomia Umana Normale, Bologna, Italy.
authors.forename: A M
authors.initials: AM
authors.lastname: Martelli
authors.forename: L
authors.initials: L
authors.lastname: Cocco
authors.forename: F A
authors.initials: FA
authors.lastname: Manzoli
mesh_terms: D016590:Aphidicolin; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D004256:DNA Polymerase I / Q000378:metabolism; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology*; D003850:Deoxyribonuclease I / Q000378:metabolism; D004224:Diterpenes / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D015530:Nuclear Matrix / Q000201:enzymology* / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D013696:Temperature
chemical_list: D004224:Diterpenes; D016590:Aphidicolin; D012965:Sodium Chloride; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D003850:Deoxyribonuclease I; D005033:Ethylmaleimide