Photoperiodic regulation of cellular retinol binding protein, CRBP1 [corrected] and nestin in tanycytes of the third ventricle ependymal layer of the Siberian hamster.
Tanycytes in the ependymal layer of the third ventricle act both as a barrier and a communication gateway between the cerebrospinal fluid, brain and portal blood supply to the pituitary gland. However, the range, importance and mechanisms involved in the function of tanycytes remain to be explored. In this study, we have utilized a photoperiodic animal to examine the expression of three unrelated gene sequences in relation to photoperiod-induced changes in seasonal physiology and behaviour. We demonstrate that cellular retinol binding protein [corrected] (CRBP1), a retinoic acid transport protein, GPR50, an orphan G-protein-coupled receptor and nestin, an intermediate filament protein, are down-regulated in short-day photoperiods. The distribution of the three sequences is very similar, with expression located in cells with tanycyte morphology in the region of the ependymal layer where tanycytes are located. Furthermore, CRBP1 expression in the ependymal layer is shown to be independent of a circadian clock and altered testosterone levels associated with testicular regression in short photo-period. Pinealectomy of Siberian hamsters demonstrates CRBP1 expression is likely to be dependent on melatonin output from the pineal gland. This provides evidence that tanycytes are seasonally responsive cells and are likely to be an important part of the mechanism to facilitate seasonal physiology and behaviour in the Siberian hamster.
Barrett
Perry
P
Molecular Endocrinology Group, Division of Obesity and Metabolic Health and Aberdeen Centre for Energy Regulation and Obesity (ACERO), Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK. pb@rri.sari.ac.uk
Ivanova
Elena
E
Graham
E Scott
ES
Ross
Alexander W
AW
Wilson
Dana
D
Plé
Helene
H
Mercer
Julian G
JG
Ebling
Francis J
FJ
Schuhler
Sandrine
S
Dupré
Sandrine M
SM
Loudon
Andrew
A
Morgan
Peter J
PJ
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001812:Blood-Brain Barrier; D006224:Cricetinae; D004805:Ependyma / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D017403:In Situ Hybridization / Q000379:methods; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D064231:Nestin; D017111:Phodopus / Q000033:anatomy & histology / Q000502:physiology*; D017440:Photoperiod; D010870:Pineal Gland / Q000502:physiology / Q000601:surgery; D043562:Receptors, G-Protein-Coupled / Q000032:analysis / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology; D020542:Third Ventricle
D015415:Biomarkers; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; D043562:Receptors, G-Protein-Coupled; D018168:Receptors, Retinoic Acid; C082927:retinoic acid binding protein I, cellular