Magic embryology: DNA controls over cell migration (Introduction)

by David Turell , Tuesday, March 30, 2021, 21:48 (1120 days ago) @ David Turell

https://www.sciencedaily.com/releases/2021/03/210330081315.htm

Working with fruit flies, scientists at Johns Hopkins Medicine say they have identified a new molecular pathway that helps steer moving cells in specific directions. The set of interconnected proteins and enzymes in the pathway act as steering and rudder components that drive cells toward an "intended" rather than random destination, they say.

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In experiments with fruit fly embryos carrying an intact Tre1 gene, cells that produce future generations of the organism, called germ cells, migrate correctly to the sex organ, known as the gonad.

"Without the Tre1 gene, however, most of the germ cells failed to meet up with other nongerm cells, or somatic cells, of the gonad," says Andrew. "Correct navigation of germ cells is important to ensure that future generations of the organism will happen."

This is not the first time that scientists noted Tre1's importance in germ cell navigation. Two research teams from Indiana University and the Massachusetts Institute of Technology had previously made the link. However, says Andrew, questions remained about what happens inside germ cells to get cells to the right place once Tre1 activates.

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At the end of the molecular cascade, a chain of actin proteins forms in a protrusion at the cell's leading edge to exert mechanical forces for movement. (my bold)

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The scientists also searched for the upstream signal that activates Tre1. They used a genetically engineered protein made by researchers at the University of California, San Francisco to track the location of a signaling protein called Hedgehog, which has previously been linked to germ cell migration, although its role in this process has been disputed.

In germ cells, Hedgehog signaling increases the membrane levels of a protein called Smoothened, which is found in the cells' leading edge protrusion where Tre1 is also found.

Comment: We know the gene in control, but not how control is precisely conducted. We remain on the outside looking into the black box of genome stepwise control. A cascade of of specialize molecules requires design. Note my bold.