Researchers at the University of Toronto have identified a gene that affects the ability of the body to adapt changing seasons. They believe the micro-RNA called miR-132/212 could be helpful in research into various mood disorders including depression.
miR-132/212 is associated with the brain’s central timekeeping system, known as the circadian clock, which is located in the suprachiasmatic nucleus. Unlike other genes, miR-132/212 does not create protein. Instead, it controls the expression of other proteins that help the circadian clock operate.
“When people study circadian rhythms, they usually look at the time of day, but a system in the same part of the brain keeps track of the time of year,” Hai-Ying Mary Cheng, an associate professor of biology at U of T Mississauga, was quoted as saying in a post on the U of T Web site written by Nicole Wahl. “By manipulating conditions, you can try to align the body’s schedule to the outside environment.”
“Now that we know that miR-132/212 affects the ability of the brain to adapt to seasons, it would be really interesting to figure out whether its misexpression may also be linked to seasonal affective disorders, given its previous connections to depression,” said Cheng.
“Not only does the circadian clock control an organism’s behavioural and physiological processes during the 24-hour day-night cycle, it also controls mechanisms that allow the body to adapt to variable day lengths associated with different seasons,” according to Lucia Mendoza-Viveros, a PhD student in the Cheng’s lab and one of the researchers who identified the micro-RNA.
The researchers were able to determine miR-132/212’s function by studying mice bred without the miR-132/212 gene.
They observed that these mice had an easier time adapting to a winter light cycle that offered eight hours of daylight and 16 hours of darkness.
The researchers also used proteomics to determine how miR-132/212 affected levels of different proteins in the central timekeeping system of the brain.
They found out that mice lacking miR-132/212 had defects in the expression of proteins that control the structure of neurons within the central clock. The researchers found that mice that had the gene had a neuronal structure that was different from mice that did not have the gene.
These structural differences affected the ability of the mice without miR-132/212 to respond properly to variations in seasonal cycles.
You can find the findings of this U of T research in the April 2017 edition of Cell Reports.