Identification of a meiotic prophase-specific nuclear matrix protein in the rat

We have identified a 110-kDa pI 5.6 phosphoprotein with DNA binding properties in the rat pachytene spermatocyte nuclear matrix. By immunoblotting and indirect immunofluorescence assays using polyclonal antibodies against the 110-kDa protein, we observed that it was germ cell nuclear matrix specific, more prominent in pachytene spermatocytes compared to premeiotic spermatogonia or postmeiotic round spermatids, and present in rat oocytes and in germ cells of mouse and monkey. We propose that this protein could play an important role in the meiotic process.