BIOL303 Lecture Notes - Lecture 8: Cytochalasin D, Pronucleus, Cell Cortex
10 Dec 2016
School
Department
Course
Professor
Document Summary
Invariant cleavage divisions: frequently mosaic-like and cell fate is specified on a cell-by-cell basis. Frequent asymmetric division unequal distribution of cytoplasmic determinants ie. autonomous specification. But conditional specification (cell-cell interactions) and regulative development is also used: outline the model for how the anterior-posterior axis is established in the c. elegans egg. Elongated egg shape defines future anterior-posterior axis. Anterior end: relates to position of sperm pronucleus. Pkc-3 (protein kinase c like), par-3 and par-6 are initially uniformly distributed throughout the cortical cytoplasm. Pkc-3 po4lates par-1 and par-2, which restricts these proteins to the internal cytoplasm. Par-1 is a kinase and phosphorylates par-3, and its binding partners leave the cortex. Net flow of cortical myosin/actin set in motion my microtubules and cyk-4=rhogap. P granules are ribonucleoprotein complexes containing translation regulators that specify the germ cells in c. elegans. They are initially distributed through egg cytoplasm after fertilization, they become localized in the posterior and are inherited by the p1 cell.
