On the association of DNA primase activity with the nuclear matrix in HeLa S3 cells.
We have reinvestigated the association of DNA primase activity with the nuclear matrix prepared from exponentially growing HeLa S3 cells. We have found that 25-30 per cent of the nuclear primase activity resists extraction with 2 M NaCl and digestion with Dnase I. Unlike previous investigations, done with the same cell line, the results showed that nuclear matrix-bound DNA primase activity represented less than 10 per cent of the total cell activity. Association of high levels of primase activity with the nuclear matrix was strictly dependent on a 37 degrees C incubation of isolated nuclei prior to subfractionation. Evidence was obtained that the method used for preparing nuclei can have a dramatic effect on the amount of primase activity which is recovered both in the postnuclear supernatant and in isolated nuclei, thus seriously affecting the interpretation of the results about the quantity of DNA primase activity bound to the nuclear matrix.
Martelli
A M
AM
Istituto di Anatomia Umana Normale, Università degli Studi di Trieste, Italy.
D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000201:enzymology; D004257:DNA Polymerase II / Q000032:analysis / Q000378:metabolism; D019915:DNA Primase; D004795:Enzyme Stability; D006367:HeLa Cells; D006801:Humans; D015530:Nuclear Matrix / Q000201:enzymology*; D012316:RNA Nucleotidyltransferases / Q000032:analysis* / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology
D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D004257:DNA Polymerase II