Borealin (green) moves from metaphase chromosomes (left) to the spindle midzone at telophase (right).

Chromosomes are getting crowded. On page 179, Gassmann et al. present their identification of a fourth chromosomal passenger protein. As part of the Aurora B kinase complex, this new protein, Borealin, helps stabilize the mitotic spindle. In a paper soon to appear in Cell, Sampath et al. identify what seems to be the same protein.

Chromosomal passenger proteins, which until now included only Aurora B, INCENP, and Survivin, have several functions during mitosis. As mitosis begins, they are dispersed along chromosomes and phosphorylate histone H3. By metaphase, they gather at centromeres, where they are needed for kinetochore function and to correct spindle attachment errors. Later they move to the spindle midzone and the plasma membrane for cytokinesis.

The identification of Borealin in human cells reveals that not all these...

The Rockefeller University Press
2004
The Rockefeller University Press
2004
You do not currently have access to this content.