Dissociation of DNA polymerase alpha-primase complex during meiosis in Coprinus cinereus.

Previously, the activity of DNA polymerase alpha was found in the meiotic prophase I including non-S phase stages, in the basidiomycetes, Coprinus cinereus. To study DNA polymerase alpha during meiosis, we cloned cDNAs for the C. cinereus DNA polymerase alpha catalytic subunit (p140) and C. cinereus primase small subunit (p48). Northern analysis indicated that both p140 and p48 are expressed not only at S phase but also during the leptotene/zygotene stages of meiotic prophase I. In situ immuno-staining of cells at meiotic prophase I revealed a sub population of p48 that does not colocalize with p140 in nuclei. We also purified the pol alpha-primase complex from meiotic cells by column chromatography and characterized its biochemical properties. We found a subpopulation of primase that was separated from the pol alpha-primase complex by phosphocellulose column chromatography. Glycerol gradient density sedimentation results indicated that the amount of intact pol alpha-primase complex in crude extract is reduced, and that a smaller complex appears upon meiotic development. These results suggest that the form of the DNA polymerase alpha-primase complex is altered during meiotic development.