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A molecular "flag" marks key genes

metronome - smallPoint to an important gene in a cell, any cell, from most any creature, and it’s likely to have a particular elongated molecular flag stuck onto the proteins wrapped around its DNA.

This isn’t just a pretty flag, plopped in for decoration. It’s thought to regulate how often this gene is transcribed, according to Anne Brunet, PhD, associate professor of genetics here. She’s the senior author of a study appearing in the July 31 issue of Cell.

Little is known about the importance of transcriptional consistency — how regularly a gene is transcribed, Brunet said. “I think the notion of transcriptional consistency is new, and it’s very important,” she commented in a release. “This is completely uncharted territory.”

It surely matters if a polymerase — that molecular workhorse that kicks off the protein-making process — spurts out dozens of copies, then chills for a bit, picking up only when it is good and ready.

This flag, abbreviated as H3K4me3, physically standardizes the transcription process, ensuring the polymerase pops off copies as if governed by a metronome — tic, tic, tic, tic, tic, tic…

The genes that are important enough to merit this transcriptional timekeeper — about 1,000 per cell, although it’s a different 1000 in each type of cell — can provide clues to the cell’s function, Brunet said. Her team plugged all the data into an online database, which other researchers can use to find the key genes in the cells of their choice.

The opportunities are endless and Brunet, for one, is psyched. Her lab focuses on the biology of aging, but this molecular flag holds all kinds of research promise.

And, as Brunet is keen to point out, it wouldn’t be possible without the megadata-crunching that’s possible at top research universities like Stanford. Other researchers had spotted this stretched-out H3K4me3, but no one had taken the time, or the computing power, to determine its extent and function, Brunet said.

“This is the new era of using available data to make really new hypotheses and new discoveries,” Brunet said.

Becky Bach is a former park ranger who now spends her time writing, exploring, or practicing yoga. She’s currently a science writing intern in the medical school’s Office of Communication & Public Affairs.

Photo by Niki Odolphie

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