IMIBIO-SL   20937
INSTITUTO MULTIDISCIPLINARIO DE INVESTIGACIONES BIOLOGICAS DE SAN LUIS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Circadian clock expression is modified in the liver of vitamin a-deficient rats.
Autor/es:
PONCE IT; REZZA IG; GOLINI RS; DELGADO SM; ANZULOVICH AC
Lugar:
San Miguel deTucuman, Argentina
Reunión:
Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2009
Resumen:
Mammalian liver has its own cellular clock machinery which
controls and synchronizes circadian gene expression. Previously,
we showed RARa, RXRa and RXRa expression display a daily
rhythmicity in the rat liver. Our objective was to investigate
whether vitamin A deficiency modifies circadian expression of
clock genes in the rat liver, by modifying retinoid receptors daily
oscillation. Holtzman rats weaned at 21 d of age were assigned to
either the experimental diet, devoid of vitamin A (vitamin Adeficient
group) or the same diet containing 4000 IU of vitamin
A/Kg diet (control group) during 3 months. Liver samples were
taken every 4 h. Total RNA was extracted using the Trizol reagent.
Transcript levels of Bmal1, Per1, Cry1 and RevErbb were
determined by RT-PCR. Protein levels were analyzed by
immunoblotting. Regulatory regions of clock genes were scanned
for retinoid receptors binding sites using the MatInspector software
(www.genomatix.de). We observed daily rhythmicity of clock -
gene and protein- expression were differentially modified in the
liver of vitamin A-deficient rats, probably, as a consequence of
temporal changes in RAR and RXR expression. Thus, vitamin A
might be essential to establish circadian clock expression in the
liver, a peripheral clock with a relevant function in daily
metabolism.
This work has been supported by NIH Grant R01-TW006974
funded by the FIC, USA.