Possible Roles for Tropomyosin During Anaphase Chromosome Movement

During anaphase, chromosomes move toward the spindle poles by forces transmitted through their kinetochore fibres. The fibres contain microtubules, as well as actin and myosin, which work together to produce the force that moves chromosomes. If tropomyosin functions in the spindle, as it does in other actin microfilament systems, then it may regulate actin filaments along kinetochore fibres. The purpose of my thesis was to investigate whether tropomyosin has possible roles during anaphase chromosome movement. Anaphase cells were treated with different inhibitory drugs against tropomyosin. Chromosome movement was altered by an upstream kinase inhibitor and was sometimes altered by a direct binding inhibitor. This may be due to possible time constraints. Furthermore, tropomyosin localized to the spindle poles and kinetochore fibres of the meiotic spindle of crane-fly primary spermatocytes. Overall, the data support the idea that tropomyosin is present in the spindle, where it may function during anaphase chromosome movement.