The mother’s response to stress can also affect her grandchildren.
Biologists at the University of Iowa discover that heat-stressed roundworm mothers, under certain conditions, have passed through the heritage of their stress exposure not only to their offspring but also to their offspring through genetic modification. Did.
Researchers led by Veena Prahlad, an associate professor at the Department of Biology and the Aging Mind and Brain Initiative, investigated how maternal roundworms react when they feel dangers such as temperature changes. animal. In a study published last year, Biologists have discovered that mother roundworms release serotonin when they feel dangerous. Serotonin migrates from the central nervous system to warn unfertilized eggs, so to speak, the warning is stored and passed to the offspring after conception.
There are many examples of such genetic cascades, even in humans. Studies show that pregnant women affected by famine in the Netherlands between 1944 and 1945 gave birth to an adult child affected by the episode, known as the Dutch famine winter. It was higher than the average for obesity, diabetes and schizophrenia.
In this study, biologists wanted to know how stress-exposed memories are stored in egg cells.
“Genes have a“ memory ”of past environmental conditions that affect gene expression even after these conditions have changed,” explains Plarad. “It is not clear how this’memory’is established, past fertilization, embryonic development, and how it persists after the embryo has grown into an adult. “This is because during embryogenesis, most organisms usually reset changes made to a gene due to past activity of the gene.”
Prahlada and her team turned to roundworms, a creature that is regularly studied by scientists for clues. They exposed their mother’s roundworm to unexpected stress and discovered that stress memory was infiltrated into their mother’s eggs by the action of a protein called heat shock transcription factor (HSF1). The HSF1 protein is present in all plants and animals and is activated by changes in temperature, salt and other stressors.
The team discovered that HSF1 mobilizes another protein, an enzyme called histone 3 lysine 9 (H3K9) methyltransferase. The latter usually acts during embryogenesis, silencing genes and erasing memories of previous activity.
But the Prague team observed something completely different.
“HSF1 has been found to work with a mechanism that normally“ resets ”the memory of gene expression during embryogenesis and instead acts to establish this stress memory,” says Prahlad.
One of these newly silenced genes encodes the insulin receptor. Insulin receptors are central to the metabolic changes caused by diabetes in humans, and when silenced, they alter the physiology, metabolism, and stress resilience of animals. Because these silencing marks persisted in the offspring, stress response strategies from those that rely on their ability to respond highly to stress, instead provide long-term protection from stressful environments that reduce stress responsiveness. It has been switched to one that depends on the mechanism to do.
“It was even more noteworthy that if the mother was exposed to stress for a short period of time, only the offspring that developed from this stressed germ cell in the womb had this memory.” Says Prarad. “The descendants of these offspring (mother’s grandchildren) had lost this memory. However, if the mother was exposed to stress for a longer period of time, the grandchildren retained this memory. Somehow, the mother’s The “dose” of stress exposure is recorded in the population. “
Researchers plan to investigate these changes further. Not only is HSF1 required for stress tolerance, elevated levels of both HSF1 and silencing marks are associated with cancer and metastasis. Since HSF1 is present in many organisms, interactions with the newly discovered H3K9 methyltransferase to promote gene silencing may have a greater impact.
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Stress on the mother can affect the biology of future generations. – Science Inquirer
https://scientificinquirer.com/2021/10/17/stress-on-mothers-can-influence-biology-of-future-generations/ Stress on the mother can affect the biology of future generations. – Science Inquirer