A POU GENE REQUIRED FOR EARLY CLEAVAGE AND PROTEIN ACCUMULATION IN THE SEA-URCHIN EMBRYO

SpOct is a POU gene expressed during oogenesis and early embryogenesis of the sea urchin, Strongylocentrotus purpuratus. In the first use of antisense technology in the sea urchin embryo, we report that disrupt ion of SpOct gene function in 1-cell zygotes by the injection of antis ense oligodeoxynucleotides arrests development prior to the first cell division. We show that single-stranded antisense oligodeoxynucleotide s specifically block cleavage, and that injection of SpOct mRNA overco mes this block. The accumulation of [S-35]methionine into zygotically synthesized protein is significantly reduced in antisense-injected emb ryos. DNA synthesis is also reduced by the antisense regimen as expect ed from the antisense inhibition of protein accumulation. That protein accumulation prior to the first cleavage is retarded by antisense tar geting of a transcription factor is very surprising in light of classi cal work showing that the activation of protein synthesis does not req uire zygotic transcription. We conclude that either some new transcrip tion is obligate for the accumulation of new protein, or that the SpOc t gene plays a novel, non-transcriptional role in this process.