Imagine you are studying the maternal factors and their role in development. It is likely to be a protein kinase, adding phosphates to other proteins. It is likely to be a transcription activator or repressor, acting on genes expressed during early development. It is likely to be a protein that removes sugars from glycosylated proteins. It is likely to be an integral-membrane protein that acts as a channel.
Cells migrate during gastrulation.
Regulated gene expression is highly important. Blastulation occurs before gastrulation. Blastulation in frogs and sea urchins differs considerably. Antennapedia genes 42. If a mesophyll cell of a leaf can be induced to divide and give rise to an entire plant, it would be considered to be a totipotent cell.