Extra chromosomes lead to deadly disease.

• Position: Cancer - Brief article

The way in which a vital protein is loaded by others into the centromere, the part of the chromosome that plays a significant role in cell division, has been identified by biologists. The findings shed new light on genome replication and may offer insights into the factors behind the production of abnormal numbers of chromosomes.

New York University researchers focused on the organization and functioning of the centromere, which is responsible for chromosome segregation--a process that ensures that replicating cells receive a complete copy of the genome. Disruption of this process can lead to the production of an abnormal number of chromosomes--a condition evident in 90% of cancer cases.

To explore the mechanics of the centromere, the researchers examined fission yeast. This species is a model organism in cell biology because its chromosome replication and the regulation of its centromere are similar to that of humans.

In the study, the researchers focused on a protein, CENP-A, present in both humans and fission yeast. They specifically examined how it is incorporated into the centromere during cell division in...