The Role of Myosin Phosphorylation on Bivalent Oscillations in Mesostoma ehrenbergii Primary Spermatocytes

The main aspect of my thesis looks at the role of myosin phosphorylation and total myosin inhibition on bivalent oscillations during prometaphase in primary spermatocytes of Mesostoma ehrenbergii. Previous studies have shown that myosin is required for proper chromosome movements in a variety of different cell types. I concentrated on increasing and decreasing the activity of myosin through inhibiting different phosphorylation pathways as well as directly inhibiting myosin. I studied the effects of enhancers and inhibitors of myosin activity on chromosome oscillations. The experiments showed that there are redundant pathways for phosphorylation of the myosin involved in spindle force production. My thesis also looks at the effects of myosin phosphorylation on distance segregation of univalents. Pharmacological studies enhancing or inhibiting myosin showed that myosin may be involved in the number of univalent movements during prometaphase, that a single phosphorylation pathway is involved, and that there are additional pathways that contribute to these movements.