Overproduced CENP-A (green) induces an ectopic kinetochore (blue) with attached microtubule (red).

KARPEN/ELSEVIER

Extra functional kinetochores can be created by overexpressing just a single protein, according to Patrick Heun, Sylvia Erhardt, Gary Karpen (University of California, Berkeley, CA), and colleagues.

The protein, called CENP-A or, in flies, CID, makes sense as an initial foundation stone for kinetochores. It substitutes for histone H3 and thus, of all kinetochore proteins, gets closest to the DNA. Human tissue culture cells overexpressing CENP-A did not make extra kinetochores, possibly because of a shortage of other factors. But in fly cells the extra CENP-A incorporated into ectopic chromosomal sites and, at some of those sites, recruited inner and outer kinetochore proteins, and motor proteins. Microtubule connections at these sites appeared to be exerting force on the chromosomes and caused chromosome breaks and aneuploidy.

Additional factors may be needed to help...

The Rockefeller University Press
2006
The Rockefeller University Press
2006
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