Digital Expression Profile of Genes Transcribed in the Heart of a Hibernating Mammal
Hibernating mammals provide a unique perspective into how various tissues and organs adapt to physiological extremes that would normally lead to pathological consequences in humans. Survival of near freezing body temperatures and reduced blood flow during hibernation is likely the result of changes in the expression of specific genes. We have carried out a comprehensive survey of mRNAs in the heart of the thirteen-lined ground squirrel (Spermophilus tridecemlineatus) before and during hibernation. The heart was chosen for this study because it is a contractile organ that must continue to work despite profound hypothermia and the lack of food for periods of up to 6 months. We used a digital gene expression assay involving high-throughput sequencing of directional cDNA libraries from hearts of active and hibernating ground squirrels to determine the identity and frequency of 3,532 expressed sequence tags (ESTs). The vast majority of sequence generated by this approach has not been reported in thirteen-lined ground squirrels or any other hibernating mammal. Statistical analysis of the active and hibernating heart expression profile indicated the differential expression of 48 genes based on a p ≤ 0.03 threshold. Several of these genes encode proteins that likely account for uninterrupted rhythmic cardiac function during hibernation including those involved in metabolism, contractility, Ca2+ handling and low temperature catalysis.
Professor of Biology, Biochemistry and Molecular Biology University of Minnesota School of Medicine Duluth, Minnesotahttp://www.d.umn.edu/biology/faculty/andrews.html
Genetic factors controlling mammalian hibernation