"We already know that a woman's age is an important factor affecting her fertility, and as such it would be important to determine if this checkpoint is reduced by the aging process," says Keith Jones. (Credit: Wanna Jean/Flickr)

aging

How a woman’s body stops ‘bad’ eggs from being fertilized

A protective ‘checkpoint’ prevents DNA damaged eggs from being fertilized, a new study shows. Damage to an egg’s DNA can result in infertility, birth defects, and miscarriages.

The damage occurs as result of the natural aging process and also as a result of women taking certain types of medication following chemotherapy or radiotherapy.

Damage to DNA during meiosis, the process that results in the formation of sperm cells and egg cells, activates the spindle assembly checkpoint (SAC) in the maturing egg, known as an oocyte, which prevents it from fully developing and stops it from being fertilized.

The SAC exists in most cells in our body, where it helps to make sure chromosomes are shared equally when a cell divides into two. But, uniquely, in oocytes the checkpoint appears to respond to DNA damage in the chromosomes.

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“My group aims to go on to understand how the initial DNA damage trigger actually manages to switch-on this checkpoint, because the connection is far from clear,” says Keith Jones, professor of biological sciences at the University of Southampton.

“However, we already know that a woman’s age is an important factor affecting her fertility, and as such it would be important to determine if this checkpoint is reduced by the aging process.

“It would also be an interesting idea to try to switch on this checkpoint in cancer cells because it would augment the actions of chemotherapeutic drugs that work by inducing DNA damage and so preventing their ability to divide.”

The Biotechnology and Biological Sciences Research Council funded the work, which is published in the journal Nature Communications.

Source: University of Southampton

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