TY - JOUR
T1 - Lecithin:retinol acyltransferase from mouse and rat liver
T2 - cDNA cloning and liver-specific regulation by dietary vitamin A and retinoic acid
AU - Zolfaghari, R.
AU - Ross, A. C.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 2000
Y1 - 2000
N2 - Lecithin:retinol acyltransferase (LRAT), present in microsomes, catalyzes the transfer of the sn-1 fatty acid of phosphatidylcholine to retinol bound to a cellular retinol-binding protein. In the present study we have cloned mouse and rat liver LRAT cDNA and tested the hypothesis that LRAT mRNA, like LRAT activity, is regulated physiologically in a liver-specific manner. The nucleotide sequences of mouse and rat liver LRAT cDNA each encode a 231-amino acid protein with 94% similarity between these species, and approximately 80% similarity to a cDNA for LRAT from human retinal pigment epithelium. Expression of rat LRAT cDNA in HEK293T cells resulted in functional retinol esterification and storage. RNA from several rat tissues hybridized with liver LRAT cDNA. However, LRAT mRNA was virtually absent from the liver of vitamin A-deficient animals, while being unaffected in intestine and testis. LRAT mRNA was rapidly induced by retinoic acid (RA) in liver of vitamin A-deficient mice and rats (P < 0.01). LRAT mRNA and enzymatic activity were well correlated in the same livers of rats treated with exogenous RA (r = 0.895, P < 0.0001), and in a dietary study that encompassed a broad range of vitamin A exposure (r = 0.799, P < 0.0001). Liver total retinol of <100 nmol/g was associated with low LRAT expression (<33% of control). We propose that RA, derived exogenously or from metabolism, serves as an important signal of vitamin A status. The constitutive expression of liver LRAT during retinoid sufficiency would serve to divert retinol into storage pools, while the curtailment of LRAT expression in retinoid deficiency would maintain retinol for secretion and delivery to peripheral tissues.
AB - Lecithin:retinol acyltransferase (LRAT), present in microsomes, catalyzes the transfer of the sn-1 fatty acid of phosphatidylcholine to retinol bound to a cellular retinol-binding protein. In the present study we have cloned mouse and rat liver LRAT cDNA and tested the hypothesis that LRAT mRNA, like LRAT activity, is regulated physiologically in a liver-specific manner. The nucleotide sequences of mouse and rat liver LRAT cDNA each encode a 231-amino acid protein with 94% similarity between these species, and approximately 80% similarity to a cDNA for LRAT from human retinal pigment epithelium. Expression of rat LRAT cDNA in HEK293T cells resulted in functional retinol esterification and storage. RNA from several rat tissues hybridized with liver LRAT cDNA. However, LRAT mRNA was virtually absent from the liver of vitamin A-deficient animals, while being unaffected in intestine and testis. LRAT mRNA was rapidly induced by retinoic acid (RA) in liver of vitamin A-deficient mice and rats (P < 0.01). LRAT mRNA and enzymatic activity were well correlated in the same livers of rats treated with exogenous RA (r = 0.895, P < 0.0001), and in a dietary study that encompassed a broad range of vitamin A exposure (r = 0.799, P < 0.0001). Liver total retinol of <100 nmol/g was associated with low LRAT expression (<33% of control). We propose that RA, derived exogenously or from metabolism, serves as an important signal of vitamin A status. The constitutive expression of liver LRAT during retinoid sufficiency would serve to divert retinol into storage pools, while the curtailment of LRAT expression in retinoid deficiency would maintain retinol for secretion and delivery to peripheral tissues.
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M3 - Article
C2 - 11108736
AN - SCOPUS:0034521929
SN - 0022-2275
VL - 41
SP - 2024
EP - 2034
JO - Journal of Lipid Research
JF - Journal of Lipid Research
IS - 12
ER -