Project description:A genome-wide association study was performed on ovaries from Siberian hamsters raised in either long or short photoperiod. Few differences between long and short photoperiod were noted at 3 wk of age, when ovarian histology was identical, whereas many differences in gene expression were noted at 8 wk of age, when ovarian histologies were markedly different. Hamsters were gestated and maintained in 16 or 10 hours of light per day, the latter short photoperiod delays sexual maturity and alters ovarian histology. Differences in gene expression were evaluated by microarray at 3 and 8 wk of age, as were changes between 3 and 8 wk of age in each photoperiod.
Project description:A genome-wide association study was performed on ovaries from Siberian hamsters raised in either long or short photoperiod. Few differences between long and short photoperiod were noted at 3 wk of age, when ovarian histology was identical, whereas many differences in gene expression were noted at 8 wk of age, when ovarian histologies were markedly different.
Project description:Photoperiod regulates genes encoding melanocortin 3 and serotonin receptors, and secretogranins expressed in the dmpARC of the Siberian hamster
Project description:Transcriptome analyses were performed to further disentangle hypothalamic control of spontaneous daily torpor in the Djungarian Hamster (Phodopus sungorus) acclimated to winter-like short photoperiod (SP). Samples of hypothalamic core areas suprachiasmatic nucleus (SCN) and paraventricular nucleus (PVN) were taken about seven hours after lights on (ZT07). After a de novo assembly of transcriptomes and a mapping against RefSeq of the house mouse (Mus musculus), data from hamsters sampled with hypothermic (HT) core body temperature during torpor arousal on a torpor-day (TD) were compared with data from hamsters sampled with normothermic (NT) core body temperature on a torpor-free day (TFD). The data must be interpreted with respect to the metabolic and seasonal context, as described in the manuscript of the original research.
Project description:Seasonal morphological brain plasticity plays a key role in driving adaptive behavioural responses. Structural changes in the brain including the hippocampus and amygdala (nucleus taeniae in birds), across photoperiods are thought to underlie seasonal shifts in emotional state. For humans, this includes manifestations of short photoperiod seasonal affective disorder (SAD). While morphological brain changes are well documented, the associated transcriptomic dynamics remain poorly understood. Here, we examined the transcriptomes of the hippocampus and amygdala or nucleus taeniae in two highly photoperiodic species, the Siberian hamster (Phodopus sungorus) and the Japanese quail (Coturnix japonica), to identify transcriptomic changes underpinning seasonal shifts in emotional state. Hamsters and quail exhibited robust physiological changes between long and short photoperiod treatment. Under short photoperiod, hamsters displayed anxiety-like behaviour (increased grooming) in the open field test, consistent with a SAD-like phenotype. Transcriptomic analysis of the amygdala in hamsters identified 76 significantly differentially expressed (DE) transcripts (including transthyretin, TTR) and prolactin receptor, PRLR as differentially expressed, but not significantly. In the quail nucleus taeniae, we found 54 DE transcripts (including tenascin-C, TNC). In the hamster hippocampus, 14 DE transcripts were found, including mahogunin ring finger-1 (MGRN1), and 31 in the quail hippocampus, including eyes absent-2 (Eya2). These findings provide novel insights into the transcriptomic mechanisms underpinning seasonal affective states and suggest conserved roles for prolactin and thyroid hormone signalling in mediating seasonal changes in physiology and affective behaviour, particularly in the Siberian hamster.
