Interaction of DNA polymerase β with GRIP1 during meiosis

DNA polymerase β (polβ) is an essential enzyme that has been shown to localize as discrete foci to the synaptonemal complex during meiosis in the mouse. To identify proteins that associate with polβ during meiosis, we employed the yeast two-hybrid screen. Here we show that a multiple PDZ domain-containing protein, the glutamate receptor interacting protein 1 (GRIP1), interacts specifically with polβ. The PDZ domain-containing proteins, including GRIP1, act as scaffolds to promote rapid and localized biochemical events that require the interaction of multiple proteins. GRIP1 localizes to discrete foci on meiotic bivalents of both spermatocyte and oocyte nuclei, and colocalizes with polβ. Together, these findings provide evidence that GRIP1 interacts with polβ during meiosis. Our findings are consistent with the possibility that GRIP1 acts as a scaffold to promote interaction between proteins that function during meiosis.