| In my thesis I studied sex-chromosome movements in crane-fly spermatocytes. During normal anaphase of these cells, autosomes start to move poleward while the two sex chromosomes remain at the equator. The sex chromosomes segregate only after the autosomes reach the poles. Each univalent sex chromosome has kinetochore fibres connected to each pole: one fibre shortens and one fibre elongates during its poleward motion. Previous studies showed that autosomal movements, with only shortening fibres, seem to utilize actin and myosin. To test whether mechanisms for sex-chromosome movements might be similar, even though sex chromosomes are attached to both poles during their movements, I treated living crane-fly cells with various inhibitors of actin, myosin, and myosin phosphorylation. Anti-actin and anti-myosin treatments often blocked sex-chromosome movements, although sometimes only temporarily. Overall, my results suggest that actin and myosin are involved in sex-chromosome anaphase movements in crane-fly spermatocytes. |
