IDENTIFICATION OF MATERNAL TRANSCRIPTS THAT PROGRESSIVELY DISAPPEAR DURING THE CLEAVAGE PERIOD OF RABBIT EMBRYOS

In order to characterize the changes that occur in the population of m aternally inherited transcripts before the transition from maternal to zygotic control of embryonic development (MZT) in mammals, we used ra bbit embryos where zygotic transcription becomes necessary only after the fourth cleavage division, during the second day that follows ferti lization. In the present work we have associated mRNA differential dis play and an RT-PCR based-method that allows amplification of the whole population of messengers to identify and characterize maternal transc ripts which are degraded throughout this early period of development. While there is no major degradation of the polyA RNA population before MZT we identify 4 transcripts which progressively disappear up until the 8-16 cell stage. We also show that the degradation of one of these maternal messengers is controlled by zygotic transcription, which is not the case for the three others. This messenger shows homology with the human FGF9 gene and is potentially a good candidate to address the question of the molecular control of maternal to zygotic transition i n early mammalian embryogenesis. (C) 1997 Wiley-Liss, Inc.