Nov 13th, Katharine Grabek: Transcriptome Dynamics in the Brown Adipose Tissue of a Hibernator

Obesity is a major health crisis in the United States. One novel, potential strategy in obesity treatment is the exploitation of brown adipose tissue (BAT). Hibernating mammals are excellent natural models for studying this tissue, because they are dependent upon BAT for rewarming during repeated arousal episodes and to maintain a minimum body temperature in torpor throughout the extended period of hibernation. Moreover, the tissue undergoes an annual cycle of atrophy and hypertrophy. In our current study, we characterized the transcriptomic changes that underlie the BAT phenotype in a circannual hibernator, the 13-lined ground squirrel, Ictidomys tridecemlineatus. Our results reveal that most gene expression changes are seasonal; transcripts involved in lipid metabolism dominate the period of hibernation, while those involved in apoptosis and RNA-processing dominate the period of spring homeothermy. Moreover, many of the “hibernation-increased” transcripts show an unexpected pattern – apparently increasing while in the low body temperature periods of torpor and early arousal. Upon further investigation, we find that the torpor-increased transcripts are enriched by polyadenylation rather than additional transcription. We hypothesize that polyadenylation protects essential transcripts from degradation during torpor and poises the selected subset for immediate utilization upon arousal.

Grabek_photoAbout Katharine

Katharine Grabek is a doctoral candidate in the Human Medical Genetics and Genomics Program at the University of Colorado, Anschutz Medical Campus. With Dr. Sandy Martin as her advisor, she has characterized the differentially expressed genes and proteins that underlie the extreme phenotype of mammalian hibernation. Her work is focused on two organs that must function at low body temperature: the heart and brown adipose tissue.

Seminar details

Wednesday Nov 13th

1 PM Lunch: sign up sheet here.

1:15 PM Seminar starts.

Location: Clark S361

Host: Carlos Bustamante

Schedule: Rosario Monge (rmonge at stanford.edu)