Inheriting a normal and intact number of chromosomes in germ cells, egg and sperm, is essential for the preservation of all species. With increasing age, the risk of the egg cell not inheriting the normal set of chromosomes increases. This results in so-called aneuploidy, which can mean either too many or too few chromosomes. The best-known example is trisomy, also known as Down syndrome in humans. Researchers at the Institute for Genome Stability in Aging and Disease, part of the CECAD Cluster of Excellence for Aging Research at the University of Cologne, have now uncovered that signals from intestinal cells significantly influence the decision whether damaged eggs are eliminated or not in the nematode C. elegans. The article has been published in Nature Communications.
The two scientists Dr. Najmeh Soltanmohammadi and Dr. Siyao Wang, together with CECAD research group leader Professor Dr. Björn Schumacher, investigated the stability of genomes in oocytes (egg cells) of C. elegans. In the germ line, the stability of the chromosomes of the oocytes is closely examined; only intact oocytes survive to be consequently fertilized. The research team now found that responses to environmental stress in the gut lead to the release of a messenger substance that regulates the animal’s germline. If control by the stress responses in the gut is absent, egg quality control fails. Despite damaged chromosomes, oocytes survive, more offspring with defective chromosome number are produced, and aneuploidy occurs. The stress response in the intestine reacts both to chromosome damage in the oocytes and to environmental influences such as increased temperatures.
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