According to biologists at the Baylor College of Medicine, limiting the copies of a gene that produces a protein affecting organ development serves to decrease fat cell size in mice, enhance their responsiveness to insulin, and increase their energy level.
The protein, called COUP-TFII (Chicken Ovalbumin Upstream Promoter Transcription Factor II), has been a subject of study for years because of its known relation to organ development. But the researchers, Dr. Ming-Jer Tsai and Dr. Sophia Tsai, did not realize its effect on metabolism until they bred mice that had only one copy of the gene responsible for making the body produce the protein.
In genetics, “copy number variation” (CNV) is when duplicate or more genes exist to perform the same function. In some cases, the greater the number of copies of a particular gene that exist, the greater the risk of certain diseases, such as cancer. But CNV can work the other way, too: a low copy number can increase the risk of certain autoimmune diseases.
The Drs. Tsai bred mice that had only one gene copy for COUP-TFII to see what would happen. They found that the mice became more lean and muscular, with smaller fat cells than their two-gene-copy counterparts, and more resistant to obesity.
They theorize that the reduction of gene copies led to less production of the protein, thus inhibiting the development of large fat cells and their attendant effects on metabolism and insulin sensitivity.
The next focus of their research will be a drug that can reduce the effect of COUP-TFII, thus creating an indirect way to treat type 2 diabetes.