Two studies from Northwestern University shed light on the main cause of birth defects and abortion, laying the foundation for further research in an important field of genetic study.
Studies consider what happens during the process that produces egg cells, which later become embryos when fertilized, and 10 – 25% of human embryos have a wrong number of chromosomes; because the egg cell is not divided properly, and this is a unique problem of egg cells.
These errors are the main cause of miscarriage and birth defects, such as Down’s syndrome, and these errors are very high, especially when women are older. Knowing why ovarian cells are most prone to miscarriage is crucial, given that women are increasingly choosing Start forming families at a later age.
The first study, published in the journal Journal of Cell Biology in March, found that oocytes use an innovative way to detect and prevent errors during cell division. The second study, published on Sept. 26 in PLOS Genetics, The new core proteins of the cell, discovered that there is a backup protein, works when partition fails; to help ensure the fetus receives the correct number of chromosomes.
“If we take these two studies together, they will reveal to us how egg cells are,” says Sadie Wignall, a senior research author and assistant professor of biological sciences at Northwestern University at the Weinberg College of Arts and Sciences. “The solution to this puzzle will be a first step to prolong women’s fertility years,” he said.
Wingal studies the composition of the so-called spindle, a detailed football structure that separates chromosomes during cell division. In most cells, there is an object called the centrosomes that helps regulate the spindle and ensures that the chromosomes can be separated specifically to send The right number of chromosomes to each newly divided cell, the spindle in the egg cells lacks the centrosomes, and this process (without a central particle) is not sufficiently studied in comparison to other cell division types, leading to important questions that are not answered, Why is it more prone to error when split?
In a study published in September, Wingal and her team discovered that in the absence of the central particles, proteins (KLP-15) and KLP-16 were necessary for dividing the cells. The researchers blocked these proteins; they found that instead of forming the spindle , The spindle structure collapsed in an anarchic round ball, and to their amazement. Despite this early imbalance, the backup proteins worked, helping to separate the chromosomes into the ends of the cell.
“We were surprised that this protein came to the rescue and made a backup; to regulate the spindle properly,” says Wingal.
The question remains why 10-25% of embryos are not viable as long as there is a backup process for these eggs. In one theory, the reason is that the backup protein changes or gets depleted as women age.
“While basic cell mechanisms may be difficult to understand, they directly affect a woman’s reproductive or infertility capacity, and my laboratory focuses on this, hoping that someday our research will help people who have fertility problems Fertility clinics “.
In addition, the lab builds parallel studies in mice based on these results, in collaboration with Teresa Woodruff, And the director of the Women’s Health Research Institute at Northwestern University, the Northwestern University Feinberg School of Medicine. The next step will be to study these mechanisms in human eggs.