Somatic H1 histone accumulation and germ layer determination in amphibian embryos

The induction of mesoderm and/or endoderm from prospective ectoderm and dorsalization of the marginal zone mesoderm may be linked to inhibition of cell cycling and DNA synthesis in early amphibian embryos. In turn, this may lead to reduction of somatic H1 histone accumulation. A greater number of cell cycles and rounds of DNA synthesis characterizes the induction of neural tissue. This is correlated with an increase of somatic H1 histone accumulation. The number of rounds of DNA replication may regulate the level of H1 histone accumulation and this may have a role in germ layer determination.