CSB328H1 Chapter Notes - Chapter 5: Blastocoel, Pronucleus, Primordium
Fertilization activates protein synthesis, dna synthesis, and the cell cycle. The activation of mitosis-promoting factor is one of the most important events in this transition to cleavage. Mpf is the major factor responsible for the resumption of meiotic cell divisions in the ovulated frog egg. Blastomeres generally progress through a biphasic cell cycle consisting of just 2 steps: m (mitosis) and s (dna. It continues to regulate the cell cycle of early blastomeres synthesis) Mpf activity is highest during m and undetectable during s. Shift between m and s in blastomeres is driven solely by the gain and loss of mpf activity. When mpf is made in these cells, they enter m phase: nuclear envelope breaks down and chromatin condenses into chromosomes. After an hour, mpf is degraded -> return to s phase. Mpf consists of 2 subunits: larger subunit, cyclin b, displays the cyclical behaviour that is key to mitotic regulation.