BIOLOGY 2B03 Lecture Notes - Lecture 10: Dapi, Nucleosome, Alanine
Document Summary
As cells enter prophase many changes occur which are initiated by the phosphoregulation of key proteins. Phosphorylation is mediated by active mpf complex, a heterodimer of mitoitic cyclin and cdk. At the end of mitosis all these changes must reverse which is done by the inactivation of mpf through ubiquitin-mediated degradation of cyclin b. One mpf is inactive, cytosolic phosphatases reverse the phosphorylation of the same key proteins to initiate chains of events that ensure the cell is rest to an interphase state. Formation of mitotic spindle phosphorylation of microtubule-associated proteins that promote microtubule instability and centrosome separation. Condensation of chromosomes - phosphorylation of condensins and histone proteins. Preparation for sister chromatic separation phosphorylation of cohesins also contributes to condensation. The breakdown of nuclear envelope phosphorylation of nuclear lamins. Fragmentation of the golgi and er phosphorylation of gm130. Early prophase the centrosomes have not separated, nuclear envelope is intact and surrounds the chromosomes, and chromosomes are beginning to condense.
