Influence of protein VIVID on Circadian clocks

Author:  Liebers Kate

Date:  June 2007

The capability of proteins to capture photons and convert the signals to longer duration and greater amplitude changes has captured the interest of Cornell University and Darthmouth College scientists. Studies on the fungus Neurospora crassa have proven how minute changes in one's genetic makeup could stimulate a series of protein modifications that ultimately account for noticeable difference in behavior in correspondence to altered biological rhythms.

Such biological rhythms, known as circadian clocks, have been thought to influence the differences in animal behavior depending on the time of the day or the season. The presence of light is considered to play a role in how circadian rhythms operate. Recent studies published in the May 18 issue of Science revealed by Brian Zoltowski and colleagues showed how light can cause conformational changes in the protein VIVID and that can have substantial results.

Brian Crane, one of Zoltowski's co-authors stated that the team is trying to discover the influences VIVID has on neighboring proteins and consequently on how the organism adjusts to the environment. He also mentioned that similar studies of biological clock components are being conducted on insects and mammals.

The findings present how VIVID, a protein that converts signals from a range of biological cues, adjusts the fungi's response to certain light by activating a complex that is responsible for resetting the circadian clock. In effect, this process allows the organism to adapt to different levels of light.

Understanding circadian rhythms can give insight to human's behavior in response to light, such as explaining why someone is a so-called morning or a night person, but although Crane noted that the mechanical components of biological clocks are similar across mammal, insect and fungus species, he said it is too early to tell if the knowledge of fungal circadian clocks could be used to treat humans.

"It would not be surprising," Crane said, "that small differences in the gene sequences of clock proteins, those that distinguish us from each other, could lead to different traits with respect to biological rhythms."

- By Kate Liebers.