Heterochromatin Protein 1 Beta Regulates Neural And Neural Crest Development By Repressing Pluripotency-Associated Gene Pou5f3.2/Oct25 In Xenopus

Background Heterochromatin protein 1 (HP1) is associated with and plays a role in compact chromatin conformation, but the function of HP1 in vertebrate embryogenesis is not understood completely.Results Here, we explore the activity of HP1 in early neural development in the frog Xenopus laevis. We show that the three isoforms of HP1, HP1 alpha, beta, and gamma, are expressed in similar patterns in the neural and neural crest derivatives in early embryos. Despite this, knockdown of HP1 beta and HP1 gamma, but not HP1 alpha, in presumptive neural tissues leads to head defects. Late pan-neural markers and neural crest specifier genes are reduced, but early neural and neural plate border genes are less affected in the morphant embryos. Further investigation reveals that neuronal differentiation is impaired and a pluripotency-associated gene, pou5f3.2/oct25, is expanded in HP1 beta morphants. Ectopic expression of pou5f3.2/oct25 mimics the effect of HP1 beta knockdown on marker expression, whereas simultaneous knockdown of HP1 beta and pou5f3.2/oct25 partially rescues expression of these genes.Conclusion Taken together, the data suggest that HP1 beta regulates transition from precursor to more differentiated cell types during neural and neural crest development in Xenopus, and it does so at least partially via repression of the pluripotency-associated transcription regulator pou5f3.2/oct25.