Expt. A; Daily Rhythm in Expression of >600 Genes in the Rodent Pineal Gland: Dominant Role of Adrenergic/cAMP Signaling. Rattus norvegicus

Biological processes are optimized by circadian and circannual biological timing systems. In vertebrates, the pineal gland plays an essential role in these systems by converting time into a hormonal signal, melatonin; in all vertebrates, circulating melatonin is elevated at night, independent of lifestyle. We have analyzed the rat pineal transcriptome at mid-day and mid-night to identify genes that exhibit night/day changes in expression. We have also used these data to characterize the non-rhythmic features of the transcriptome that set the pineal gland apart from other tissues by comparing them to the median expression in other rat tissues as found in the Genomics Institute of the Novartis Research Foundation (GNF), Entrez Gene Expression Omnibus (GEO) dataset GDS589. Keywords: Time course (2 points) Overall design: Rat pineal glands were obtained at mid-day and mid-night for RNA extraction and hybridization to Affymetrix microarrays. Triplicates of pooled pineal glands were analyzed at each timepoint.