Gene for 'fullness' identified

Researchers have identified a gene in roundworms that is involved in the feeling of fullness and the need to sleep after a meal.

There is a similar gene in humans, so this research might eventually lead to obesity treatments that prevent overeating and stimulate the desire to exercise.  

'When animals are malnourished they seek out food by roaming their environment. When they're well fed they have no need to roam, and when they're fully sated they enter a sleep-like state,' said Dr Roger Pocock of Monash University in Victoria, Australia, who led the research, which was published in the journal PNAS.

The research team monitored the roundworm – Caenorhabditis elegans – and its responses to different foods while analysing individual neurons within its brain. They identified that, much like with humans, when the roundworms were presented with foods high in sugar or fat, they overate. When only low-quality food was available, they began roaming in search of food.

The researchers then identified a gene in the roundworm which encodes a transcription factor called ETS-5. This protein appears to link the brain and the intestines – a signal is sent to the brain when the intestines have stored enough fat, and this stops the organism searching for more food.  

The roundworm has only 302 neurons, but shares 80 percent of its genes with humans, making it a 'great model system to investigate and gain a better understanding of processes like metabolism', said Dr Pocock.

The UK has the highest obesity rates in Europe, with one in four British people classified as obese. 

Dr Pocock said that this is the first time a gene regulatory molecule has been implicated in the brain-intestinal control of eating and activity. 'The ETS family of genes is present in humans and has previously been linked to obesity regulation. Now that we've learned this gene family controls food intake through a feedback system to the brain, it represents a credible drug target for the treatment of obesity.'