Dissociation of DNA polymerase α-primase complex during meiosis inCoprinus cinereus

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Abstract
Previously, the activity of DNA polymerase α was found in the meiotic prophase I including non-S phase stages, in the basidiomycetes, Coprinus cinereus. To study DNA polymerase α during meiosis, we cloned cDNAs for the C. cinereus DNA polymerase α 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 α-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 α-primase complex by phosphocellulose column chromatography. Glycerol gradient density sedimentation results indicated that the amount of intact pol α-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 α-primase complex is altered during meiotic development.