Declining Centromere Strength Compromises Meiotic Chromosome Segregation In Aging Oocytes
As women age, the quality of their egg cells can decline, leading to a higher risk of infertility, miscarriage, and developmental disorders. A major reason for this is errors in how chromosomes are sorted during the egg cell’s special division process, called meiosis.
A recent study sheds light on a crucial factor contributing to these age-related problems: the weakening of structures called centromeres. Centromeres are like the “handles” on chromosomes that the cell’s machinery uses to pull them apart accurately during division.
Scientists observed that in older egg cells, the levels of important proteins (CENP-A and CENP-C) that make up these centromeres are significantly reduced. This reduction makes the centromeres weaker, compromising their ability to properly attach to the cellular “ropes” (spindle microtubules) that guide chromosome movement. As a result, chromosomes can become misaligned, leading to an incorrect number of chromosomes in the resulting egg cell, a condition known as aneuploidy.
Intriguingly, when researchers introduced extra amounts of one of these key proteins, CENP-C, into older egg cells, they saw an improvement in chromosome alignment. This suggests that bolstering centromere strength could be a potential strategy to combat age-related declines in egg quality. The study also noted that disorganization of the spindle, the structure responsible for chromosome segregation, further contributes to these issues in aging egg cells.
Source: link to paper