Early embryonic expression of XLPOU-60, a Xenopus POU-domain protein.

XLPOU-60 is a Xenopus POU-domain gene whose expression is tightly controlled during early development at transcriptional, post-transcriptional, translational, and post-translational levels. We report the expression pattern of the XLPOU-60 protein; it is first detectable in the stage V oocyte and accumulates rapidly following fertilisation, reaching a peak at the time of the mid-blastula transition. In the blastula, XLPOU-60 protein translated from injected synthetic mRNA enters nuclei. During gastrulation, both transcript and protein are rapidly down-regulated in a cell-autonomous manner; down-regulation is not dependent on cell-cell contact or induction by activin in an animal cap assay. For the mRNA, this down-regulation correlates with changes in the length of its poly(A) tail and is dependent on sequences in the untranslated regions of the transcript. On the basis of its protein expression pattern and known DNA-binding properties, we speculate that XLPOU-60 may play a role in the control of early transcriptional events in the Xenopus embryo.