SAN FRANCISCO, April 22 - The liver and heart beat to different time keepers, microarray technology has allowed researchers to learn.
Scientists from Harvard University and Northeastern University used an Affymetrix mouse array to show that gene expression of circadian rhythm in the murine liver and heart are distinct from each other.
"The circadian clock in the heart and liver, as far as we know, has the exact same molecular machinery, but the genes regulating circadian rhythms are almost completely different," said lead investigator Charles Weitz, associate professor of neural biology at Harvard Medical School. "It really points to how big a gap there is between our understanding of genes and control of physiological processes."
Researchers identified 575 genes in the liver and 462 in the heart associated with circadian expression patterns. These genes provide clues to peripheral, tissue-specific clocks distinct from control of circadian rhythm associated with the brain, the team found.
"The divergence of liver and heart in the timing and content of circadian gene regulation suggests a specialized role of circadian clocks in each tissue," the researchers report in their findings, published in the current Nature.
Weitz, who credited the gene chip with allowing novel in vivo studying of circadian clocks, called the research "very early days" and years away from clinical application.
Treatments for jet lag and seasonal affective disorder are the most likely targets for any human health-oriented applications, according to Dennise Dalma, scientific communications manager at Affymetrix.
Unique applications for microarray use, such as studying circadian clocks, are becoming more common, added Dalma.
Weitz plans to use similar arrays to study gene regulation of circadian rhythm in other organs, including the lungs and kidneys.