Cienciaes.com: The mysterious gene that causes cancer or neuronal degeneration

by time news May 25, 2023

May 25, 2023

2020-12-22 23:00:00

The cells in our bodies are among the most complex nanomachines in the entire universe. They are made up of thousands of pieces that must fit together to form complex dynamic systems, and failures in any one of these pieces can cause the cell to fall ill. Sometimes, as in cancer, it is enough for a single cell to become diseased so that its reproductive control system fails for a tumor to arise and kill the entire organism.

We know that cancer is normally caused by mutations in genes that, in effect, control cell division in one way or another. But in addition to the genes that control cell reproduction, we still have at least one other type of gene that, when mutated, can also cause cancer. This class of genes are involved in the production of proteins that manage the storage and functioning of the ADN on the chromosomes.

so that the ADN to fit inside the cell nucleus, it must be tightly coiled around proteins dedicated to this function. The most important among them are the so-called histones, which form nuclei around which the ADN it coils up, forming the so-called nucleosomes. Chromosomes are thus made up of thousands of nucleosomes, which in turn are further coiled around each other.

He ADN it is not always coiled up at every moment and must be uncoiled here and there to allow genes to function. Mutations in some of the histones affect the winding and unwinding dynamics and thus the function of multiple genes. For this reason, some of the histone mutations also cause cancer. One of these histones is called H3.3.

When the gene mutations of this histone present in some types of cancer have been analyzed, it has been possible to verify that, as expected, the mutations have only occurred in cancer cells, but are not present in the rest of the cells. of the organism. However, it is also possible that there are mutations in the histone H3.3 gene that have occurred in the sperm or egg that originated the organism and that, consequently, are found in all its cells. This had not yet been detected.

Now, an international group of more than 150 researchers has identified and studied 46 patients who have mutations in one of the two copies of the H3.3 gene in all cells of the body. These patients suffer from a syndrome characterized by developmental delay, neuronal degeneration, epilepsy, and facial deformities, including skull abnormalities.

Reference:
Laura Bryant, et al (2020). Histone H3.3 beyond cancer: Germline mutations in Histone 3 Family 3A and 3B cause a previously unidentified neurodegenerative disorder in 46 patients. Sci. Adv. 2020; 6: eabc9207. 2 December 2020.

Jorge Laborda 12-23-20

Works by Jorge Laborda.

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