Expression of Cre recombinase in mouse oocytes: a means to study maternal effect genes.

., 1998). Thesematernally derived transcripts are responsible for thecompletion of meiosis, initiation of mitosis, activation ofthe embryonic genome, and completion of the transfor-mation of the highly differentiated oocyte into a totipo-tent embryonic cell. To study the effect of specific ma-ternal transcripts on these processes, we have sought toestablish a Cre-