title: Orchestration of gene expression across the seasons: Hypothalamic gene expression in natural photoperiod throughout the year in the Siberian hamster.
abstract: In nature Siberian hamsters utilize the decrement in day length following the summer solstice to implement physiological adaptations in anticipation of the forthcoming winter, but also exploit an intrinsic interval timer to initiate physiological recrudescence following the winter solstice. However, information is lacking on the temporal dynamics in natural photoperiod of photoperiodically regulated genes and their relationship to physiological adaptations. To address this, male Siberian hamsters born and maintained outdoors were sampled every month over the course of one year. As key elements of the response to photoperiod, thyroid hormone signalling components were assessed in the hypothalamus. From maximum around the summer solstice (late-June), Dio2 expression rapidly declined in advance of physiological adaptations. This was followed by a rapid increase in Mct8 expression (T3/T4 transport), peaking early-September before gradually declining to minimum expression by the following June. Dio3 showed a transient peak of expression beginning late-August. A recrudescence of testes and body mass occurred from mid-February, but Dio2 expression remained low until late-April of the following year, converging with the time of year when responsiveness to short-day length is re-established. Other photoperiodically regulated genes show temporal regulation, but of note is a transient peak in Gpr50 around late-July.
authors.affiliation: University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Petri
authors.affiliation: University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany.
authors.forename: Victoria
authors.initials: V
authors.lastname: Diedrich
authors.affiliation: Rowett Institute for Nutrition and Health, University of Aberdeen, Greenburn Road Bucksburn, Aberdeen AB21 9SB, UK.
authors.forename: Dana
authors.initials: D
authors.lastname: Wilson
authors.affiliation: Rowett Institute for Nutrition and Health, University of Aberdeen, Greenburn Road Bucksburn, Aberdeen AB21 9SB, UK.
authors.forename: José
authors.initials: J
authors.lastname: Fernández-Calleja
authors.affiliation: Zoological Institute, University of Hamburg, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Herwig
authors.affiliation: University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Steinlechner
authors.affiliation: Rowett Institute for Nutrition and Health, University of Aberdeen, Greenburn Road Bucksburn, Aberdeen AB21 9SB, UK.
authors.forename: Perry
authors.initials: P
authors.lastname: Barrett
mesh_terms: D000818:Animals; D006224:Cricetinae; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D017111:Phodopus; D017440:Photoperiod; D012621:Seasons; D013963:Thyroid Hormones / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D013963:Thyroid Hormones