ETHANOL-INDUCED INTRACELLULAR CALCIUM MOBILIZATION RAPIDLY ALTERS GENE-EXPRESSION IN THE MOUSE BLASTOCYST

The induction of intracellular Ca2+ release in pre-implantation mouse embryos accelerates their subsequent rate of development in vitro thro ugh a calmodulin-dependent mechanism [Stachecki J.J., Armant D,R, Tran sient release of calcium from inositol 1,4,5-trisphosphate-specific st ores regulates mouse pre-implantation development. Development 1996; 1 22: 2485-2496], To examine the hypothesis that intracellular Ca2+ sign aling alters embryonic gene expression, individual transcript levels w ere compared by mRNA differential display before and 1 h after intrace llular Ca2+ mobilization with ethanol in mouse blastocysts. Ten up-reg ulated and four down-regulated genes were observed, representing 3.5% of approximately 400 transcripts that were resolved. After sequencing, most of the DNA fragments appeared to be novel; however, two amplicon s that increased after Ca2+ mobilization were identified as arginase a nd ubiquitin conjugating enzyme (E2). The up-regulation of arginase mR NA (3.5-fold after 2 h) was confirmed by reverse transcription and the polymerase chain reaction using specific oligonucleotide primers deri ved from the deduced mouse embryo sequence. A corresponding 2.5-fold i ncrease in arginase enzymatic activity peaked 9 h after ethanol exposu re. Increased expression of arginase and other genes may mediate the o nset of rapid cell proliferation and differentiation that is induced b y Ca2+ signaling during pre-implantation development,