CELL DIFFERENTIATION AND DELAYED SEPARATION OF ANAPHASE CHROMOSOMES

I-18: The Role of Sex Chromosomes in Female Germ Cell Differentiation

Background When gonadal sex reversal occurs in mammalian species, the resultant XX males and XY females become infertile or subfertile, suggesting critical roles of sex chromosomes in germ cell differentiation. The objective of our study is to clarify the mechanism of infertility in the B6.YTIR (XY) sex-reversed female mouse, which can be attributed to a failure in the second meiotic division i...

Separation of lentil root tip chromosomes by colchicine

Sds22 and Repo-Man keep anaphase chromosomes moving

W urzenberger et al. identify two phosphatase-targeting proteins that help chromosomes to segregate properly during anaphase. In early mitosis, the kinase Aurora B localizes to centromeres, where it eliminates incorrect attachments to the mitotic spindle by phosphorylating microtubule-binding kinetochore proteins like Dsn1. When sister chroma-tids are attached to opposite spindle poles, tension...

Anaphase Spindle Mechanics Prevent Mis-Segregation of Merotelically Oriented Chromosomes

Merotelic kinetochore orientation is a kinetochore misattachment in which a single kinetochore is attached to microtubules from both spindle poles instead of just one. It can be favored in specific circumstances, is not detected by the mitotic checkpoint, and induces lagging chromosomes in anaphase. In mammalian cells, it occurs at high frequency in early mitosis, but few anaphase cells show la...

Anaphase A: Disassembling Microtubules Move Chromosomes toward Spindle Poles

The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting fibers, and anaphase B, separation of the two poles from one another via spindle elongation. I focus here on a...