The spindle fibres move chromosomes to the metaphase plate at the centre of the cell and hold them in position.
Unattached or mal-orientated chromosomes generate a signal to delay the onset of anaphase until all pairs of sister chromatids are properly aligned on the metaphase plate.This signal is transduced by a relay of spindle-checkpoint proteins which inhibits cell division by inhibiting the anaphase promoting complex.Following attachment and alignment of all the chromosomes at metaphase, the checkpoint signal is silenced and some metaphase proteins are destroyed whilst others that are needed for anaphase are activated.
Unattached or mal-orientated chromosomes generate a signal to delay the onset of anaphase until all pairs of sister chromatids are properly aligned on the metaphase plate.This signal is transduced by a relay of spindle-checkpoint proteins which inhibits cell division by inhibiting the anaphase promoting complex.Following attachment and alignment of all the chromosomes at metaphase, the checkpoint signal is silenced and some metaphase proteins are destroyed whilst others that are needed for anaphase are activated.