First ever ‘pioneer’ factor found in plants enables cells to change their fate

Cells don’t express all the genes they contain all the time. The portion of our genome that encodes eye color, for example, doesn’t need to be turned on in liver cells. In plants, genes encoding the structure of a flower can be turned off in cells that will form a leaf.

These unneeded genes are kept from becoming active by being stowed in dense chromatin, a tightly packed bundle of genetic material laced with proteins.

In a new study in the journal Nature Communications, biologists from the University of Pennsylvania identify a protein that enables plant cells to reach these otherwise inaccessible genes in order to switch between different identities. Called a “pioneer transcription factor,” the LEAFY protein gets a foothold in particular portions of the chromatin bundle, loosening the structure and recruiting other proteins that eventually allow genes to first be transcribed into RNA and then translated into proteins.

Using an experimental technique whereby flowers can be coaxed to form from plant roots, biologists led by Doris Wagner uncovered a protein that enables for the initial loosening of chromatin that can allow new proteins to be made and plants to take on different forms. (Image: Courtesy of the Wagner laboratory)