BIO380H5 Lecture Notes - Lecture 3: Methylation, Demethylation, Blastomere
Document Summary
Inner cell mass responsible for the embryo development. Cavitation theories: an earl manifestation of activation of zygote"s genome is the polarization of the blastomeres. The inner daughter cell will stay nonpolar and stay as inner cell mass: until the stage of 16- cells, the cells can be transformed to switch between being polar or non-polar. By the stage of 32 cell, this will be almost lost. Molecular differences between the inner cell mass and the trophoblasts: the upregulation of certain genes on blastomeres will determine their position in the future egg, cdx-2: is essential for trophoblastic differentiation. Mutation = failure to implantation: oct-4, nanog, sox-2: are essential for the development of the inner cell mass, oct-4 - the features of pluripotency (produce any type of cells within the embryo). This decrease after several divisions, but retained in the primordial germ cells. Totipotent pgc (produce inner cell mass or trophoblasts: nanog, sox-2 regulate the expression of genes that control cellular differentiation.
