Correlations between cell fate and the distribution of proteins that are synthesized before the midblastula transition in Xenopus

Abstract

The proteins synthesized before the 512-cell stage by Xenopus blastomeres with different fates were compared by one dimensional PAGE. Blastomeres that contributed more progeny to antero-dorsal axial structures produced proportionately more of two proteins of 225000 and 245000 daltons. Additionally, these proteins were reversibly increased in ventralized embryos and were decreased in dorsalized embryos. These observations indicate that some proteins that are synthesized during cleavage stages are expressed to different degrees in different regions of the embryo, that their expression can be correlated to cell fate in the normal embryo, and that their expression is altered quantitatively in dorsalized and ventralized embryos. The inverse relationship between the production of these proteins and the potential to produce dorsal structures in the normal and in dorsalized/ventralized embryos is consistent with a model in which cell fate is influenced by a gradient of particular proteins.

Neural transcription factors bias cleavage stage blastomeres to give rise to neural ectoderm

“…It is most interesting that there are reports of cleavage stage posttranscriptional differences between 16-cell blastomeres. Protein synthesis studies identified unique protein bands/spots from dorsal versus ventral animal 16-and 32-cell blastomeres (Klein and King, 1988;Miyata et al, 1987). A recent proteomic analysis showed that Gmnn protein is significantly enriched in D11 versus V11 blastomeres (Lombard-Banek et al, 2016), and D11 and V11 blastomeres have metabolite differences that affect cell fate decisions (Onjiko et al, 2015).…”

Molecular asymmetry in the 8-cell stage Xenopus tropicalis embryo described by single blastomere transcript sequencing

“…The nature and identities of these dorsal determinants are not currently well defined. Previous experiments have shown that these putative cytoplasmic factors may be mRNA or proteins ( Klein and King, 1988 , Miyata et al, 1987 , Shiokawa et al, 1984 ). Further, it has been argued that cytoplasmic polyadenylation may be the mechanism for the change in dorsal inducing activity of total RNA isolated from the dorsal lineage between the 8- and 16-cell stages ( Pandur et al, 2002 ).…”