An anonymous reader quotes a report from Phys.Org: Cells will ramp up gene expression in response to physical forces alone, a new study finds. Gene activation, the first step of protein production, starts less than one millisecond after a cell is stretched — hundreds of times faster than chemical signals can travel, the researchers report. The scientists tested forces that are biologically relevant — equivalent to those exerted on human cells by breathing, exercising or vocalizing. They report their findings in the journal Science Advances.
In the new work, the researchers observed that special DNA-associated proteins called histones played a central role in whether gene expression increased in response to forces that stretched the cell. Histones regulate DNA, winding it up to package it in the nucleus of the cell. One class of histones, known as Histone H3, appear to prevent force-responsive gene expression when methylated at an amino acid known as lysine 9. Methylation involves adding a molecular tag known as a methyl group to a molecule. The scientists observed that H3K9 methylation was highest at the periphery of the nucleus and largely absent from the interior, making the genes in the interior more responsive to stretching. The researchers found they could suppress or boost force-responsive gene expression by increasing or decreasing H3K9 histone methylation. The scientists also tested whether the frequency of an applied force influenced gene expression. They found that cells were most responsive to forces with frequencies up to about 10-20 hertz.
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