BCL9L and caspase-2—new guardians against aneuploidy

Every time cell divides, the chromosomes must be duplicated and segregated equally into the two daughter cells. Duplication and segregation of chromosomes is a dynamic process that involves highly orchestrated processes to ensure faithful transfer of the genetic information. Infrequently, errors in mitosis can occur that cause the cells to missegregate one or more chromosomes, which leads usually to irreversible cell cycle arrest or cell death. In rare occasions, some of these cells survive to give rise to daughter cells with either loss or gain of chromosomes; a condition known as “aneuploidy”. In humans, aneuploidy is rarely compatible with life and is recognized as the major cause of spontaneous miscarriages. At the cellular level, depending on the severity of the errors, the propagation of cells after chromosome missegregation is restricted by induction of G1 arrest or apoptosis or by severe proliferation defect of the arising aneuploid progeny.