Tanycytes around the third ventricle and the adjacent mediobasal hypothalamus are crucial components to trigger photoperiodic responses in breeding and metabolism. In mammals, tanycytes are known to regulate hypothalamic thyroid hormone conversion, a process which is linked to seasonal reproduction. They are further involved in retinoic acid signalling, neurogenesis, and nutritional gatekeeping, all of which have been linked to the photoperiodic regulation of metabolism. The region is neuroanatomically conserved between mammals and birds but, apart from the hypothalamic thyroid hormone conversion, little is known about the functional roles of tanycytes in birds. We, hence, aimed to give a comprehensive characterisation of gene expressions in avian tanycytes and surrounding cells under different photoperiodic reproductive and metabolic states. For this purpose, we used the Svalbard ptarmigan (Lagopus muta hyperborea), a high-Arctic bird species which shows pronounced seasonal rhythms in breeding and body mass. We applied a simple photoperiodic extension protocol to short-day adapted birds to trigger a long-day response which is marked by initiation of breeding and loss in body mass. After several weeks under a long photoperiod, the innate development of photorefractoriness led to a reversal to the short-day phenotype marked by the termination of breeding and gain in body mass. We sampled birds at different seasonal states and used laser-capturing and RNAseq to correlate the seasonal phenotype with the gene expressions in tanycytes and the surrounding area.

The here contained dataset includes behavioural data, gene expression data (raw and cpm) and results from statistical analyses and GO enrichment analyses. Furthermore the EdgeR RNA seq script is attached.

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