title: Influence of temperature on the liver circadian clock in the ruin lizard Podarcis sicula.
abstract: Reptiles represent an interesting animal model to investigate the influence of temperature on molecular circadian clocks. The ruin lizard Podarcis sicula lives in a continental climate and it is subjected to wide range of environmental temperatures during the course of the year. As consequence, ruin lizard daily activity pattern includes either the hibernation or periods of inactivity determined by hypothermia. Here we showed the rhythmic expression of two clock genes, lPer2 and lClock, in the liver of active lizards exposed to summer photo-thermoperiodic conditions. Interestingly, the exposition of lizards to hypothermic conditions, typical of winter season, induced a strong dampening of clock genes mRNA rhythmicity with a coincident decrease of levels. We also examined the qualitative and quantitative distribution of lPER2 and lCLOCK protein in different cellular compartments during the 24-h cycle. In the liver of active lizards both proteins showed a rhythmic expression profile in all cellular compartments. After 3 days at 6 degrees C, some temporal fluctuations of the lCLOCK and lPER2 are still detectable, although, with some marked modifications in respect to the values detected in the liver of active lizards. Besides demonstrating the influence of low temperature on the lizard liver circadian oscillators, present results could provide new essential information for comparative studies on the influence of temperature on the circadian system across vertebrate classes.
authors.affiliation: Dipartimento di Scienze Morfologico-Biomediche, Sezione di Anatomia e Istologia, Università di Verona, Italia.
authors.forename: Manuela
authors.initials: M
authors.lastname: Malatesta
authors.forename: Elena
authors.initials: E
authors.lastname: Frigato
authors.forename: Beatrice
authors.initials: B
authors.lastname: Baldelli
authors.forename: Serafina
authors.initials: S
authors.lastname: Battistelli
authors.forename: Augusto
authors.initials: A
authors.lastname: Foà
authors.forename: Cristiano
authors.initials: C
authors.lastname: Bertolucci
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000235:genetics / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D022781:Hepatocytes / Q000166:cytology / Q000648:ultrastructure*; D007150:Immunohistochemistry; D008099:Liver / Q000166:cytology / Q000502:physiology*; D008116:Lizards / Q000235:genetics / Q000502:physiology*; D016253:Microscopy, Immunoelectron; D009687:Nuclear Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D009687:Nuclear Proteins