Cell Biology

Checking Centrosomes

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Science  16 Aug 2002:
Vol. 297, Issue 5584, pp. 1097
DOI: 10.1126/science.297.5584.1097c

Getting cell division right is vital. Aneuploidy, the loss or addition of a single chromosome, can be lethal or result in uncontrolled growth. A high degree of aneuploidy is seen in many human tumors and correlates with a poor prognosis. During cell division in normal cells, two centrosomes help to form the mitotic spindle poles. The mitotic spindle directs the correct segregation of chromosomes. Like chromosomes, centrosomes are duplicated once during each cell cycle. This duplication is tightly regulated: Additional copies of the centrosomes can cause the formation of multiple spindles, mis-segregation, and aneuploidy.

Borel et al. show how centrosome number can become amplified. First, defective cells inappropriately receive four rather than two copies of each chromosome, as well as extra centrosomes, because of mis-segregation. If these tetraploid cells fail to arrest their growth, the additional centrosomes cluster at a single spindle pole in the subsequent cell division, forming a regular two-pole spindle and maintaining the abnormal chromosome number. At each division, cells possessing such supernumerary centrosomes have the potential to form multiple spindle poles and aberrantly segregate their chromosomes, resulting in high levels of aneuploidy. — GR

Proc. Natl. Acad. Sci. U.S.A.99, 9819 (2002).

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