Genome complexity: new transcription factors found (Introduction)

by David Turell , Thursday, July 08, 2021, 17:09 (1023 days ago) @ David Turell

Transcription factors control gene expression:

https://phys.org/news/2021-07-essential-genes.html

"Proteins known as transcription factors act as switches that regulate the expression of nearby genes, but the identity of some of these genetic levers has so far remained mysterious. Now, researchers from the Schübeler group have pinpointed a new switch that regulates essential genes in the mouse and the human genome. Identifying missing gene switches and their function is critical to fully understand the molecular basis of health and disease.

"If the human genome were a company, transcription factors would be the top-level managers, controlling when and how much genes are turned on in specific cells. These proteins typically bind short strings of DNA called 'motifs'. Scientists estimate that there are up to 2,800 transcription factors, but binding motifs have been identified for only about 800 of them.

"One DNA motif that is bound by no known transcription factor is called the CGCG element, as it contains two cytosine nucleotides sitting next to guanine nucleotides. This motif is associated with highly expressed genes across human tissues and is commonly found within specific DNA regulatory regions where most of our genes start to be read.

***

"...the researchers detected the Btg3-associated nuclear protein (BANP) as the only protein bound to the CGCG motif.

"'This protein has been known before, but it was thought to repress gene activity at the periphery of the nucleus," Grand says. "We show that it does quite the opposite: it's a very potent activator of gene expression."

"The team found that BANP has a high affinity for the CGCG motif, both in mouse and human cells. Removing BANP in stem cells causes a decrease in the expression of several genes, including essential ones involved in key biological processes such as transcription, DNA replication, and the assembly of chromatin—the complex of DNA and proteins that forms chromosomes. The researchers observed similar drops in gene expression also when BANP was removed in neurons.

"After binding to specific regulatory regions within the genome, BANP makes the DNA accessible to other proteins. This likely helps regulatory factors to bind and control gene expression. The findings, published today in Nature, could redefine how essential genes are controlled. "These genes, which are expressed in every cell of the body but at different levels, could be regulated by the same switch present in all cells rather than by a series of transcription factors across different cell types", Grand says."

Comment: More junk DNA bites the dust. Bit by bit, research teases apart the controls. Not by chance.