Spindle tubulin and MTOC asymmetries may explain meiotic drive in oocytes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30054463.
- Also identified by DOI 10.1038/s41467-018-05338-7 and PMC identifier 6063951.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
In the first meiotic division (MI) of oocytes, the cortically positioned spindle causes bivalent segregation in which only the centre-facing homologue pairs are retained. 'Selfish' chromosomes are known to exist, which bias their spindle orientation and hence retention in the egg, a process known as 'meiotic drive'. Here we report on this phenomenon in oocytes from F<sub>1</sub> hybrid mice, where parental strain differences in centromere size allows distinction of the two homologue pairs of a bivalent. Bivalents with centromere and kinetochore asymmetry show meiotic drive by rotating during prometaphase, in a process dependent on aurora kinase activity. Cortically positioned homologue pairs appear to be under greater stretch than their centre-facing partners. Additionally the cortex spindle-half contain a greater density of tubulin and microtubule organising centres. A model is presented in which meiotic drive is explained by the impact of microtubule force asymmetry on chromosomes with different sized centromeres and kinetochores.
Medical subject headings
- Meiosis
- Microtubule-Organizing Center
- Oocytes
- Spindle Apparatus
- Tubulin