Fate of meiotic lamin C2 in rat spermatocytes cultured in the presence of okadaic acid

The fate of nuclear envelope proteins during the pachytene/metaphase I tran sition was investigated in rat spermatocytes cultured in vitro in the prese nce of the phosphatase inhibitor okadaic acid (OA). Under these experimenta l conditions lamin B1 and the lamina-associated proteins 2 (LAPs2) behave a s already described in other cell types. In contrast to these results, meio tic la min C2 appears to be degraded after addition of OA to the spermatocy te culture medium as this lamin was no longer detectable by immunofluoresce nce microscopy or by immunoblotting. Taking into account the peculiarities of the lamin C2 primary structure, it is tempting to speculate that degrada tion of this protein represents a critical step in the process of disassemb ly of the spermatocyte nuclear envelope.