Improper microtubule-chromosome attachment, termed merotely, represents a specific mechanism of chromosome missegregation observed in chromosomally unstable cells. This defect in kinetochore-microtubule attachment results in incorrect chromosome segregation during mitosis. [@thompson_examining_2008]
Definitions
- merotely
- chromosome missegregation
- chromosomal instability
- kinetochore
- mitosis
- microtubule-chromosome attachment
Synthesis
Multiple sources establish that merotely, an erroneous kinetochore-microtubule attachment where a single kinetochore attaches to microtubules from both spindle poles, serves as a critical mechanism driving chromosome missegregation and chromosomal instability in cells with genomic instability. The mechanistic pathway is well-supported: cells with extra centrosomes pass through a transient multipolar spindle intermediate state during which merotelic attachment errors accumulate before centrosome clustering occurs, and this accumulation directly precedes elevated chromosome missegregation rates during subsequent anaphase. Experimental evidence demonstrates that artificially elevating merotely rates can induce chromosomal instability even in previously stable near-diploid cells, confirming merotely’s causal role and establishing it as the key mechanistic link between centrosome amplification and chromosomal instability that had remained unclear in earlier research. However, an important unresolved question persists: while merotely-driven missegregation is sufficient to establish chromosomal instability, chromosome missegregation alone compromises proliferation in diploid cells, indicating that additional phenotypic changes beyond merotely are required for viable aneuploid cells to propagate with sustained chromosomal instability.
Related
- Multipolar spindle intermediate allows merotelic attachment accumulation
- CIN exists independently of classic mitotic defects in most cells
- CIN causality toward aneuploidy was previously unanswered
- Elevated merotely generates CIN in stable near-diploid cells
- CENP-E reduction generates aneuploidy and chromosomal instability
- Missegregation alone insufficient for aneuploid cell propagation