Vitamin A, the collective name for a group of related retinoids, is essential for normal development and growth in animals. Too little of too much results in a wide variety of biological defects, and in addition, increases toxicity caused by alcohol and various environmental toxins. The biologically active retinoid is retinoic acid (RA), and its concentration within cells is critical to health. Previous studies have indicated that a cellular retinoic acid-binding protein (CRABP) plays a major role in maintaining intracellular RA at a constant concentration. However, because CRABP is so vital in this regard, mutation and other manipulation that greatly reduce or eliminate this protein are generally lethal to the organism, and hence cannot be used to study CRABP function. The major goal of this proposal is to understand the positive and negative regulatory elements of CRABP gene and to create specific changes in this gene so its expression is altered but not eliminated in animals. Specifically, we will 1. determine the region of the gene essential for its regulation, by systematically deleting portions of the 5' region of the gene fused to a LacZ reporter, and 2. create transgenic mice in which CRABP is expressed in tissues normally not expressing this protein, as well as animals in which normal CRABP expression is blocked. Taken together, these studies should illustrate the interaction of RA and CRABP and the mechanisms that regulate intracellular RA concentration, and ultimately lead to better preventive/therapeutic application of vitamin A in humans.

Project Start
1993-08-01
Project End
1998-07-31
Budget Start
1997-08-01
Budget End
1998-07-31
Support Year
5
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Pharmacology
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Wei, L N; Chang, L; HU, X (1999) Studies of the type I cellular retinoic acid-binding protein mutants and their biological activities. Mol Cell Biochem 200:69-76
Yu, Z; Lee, C H; Chinpaisal, C et al. (1998) A constitutive nuclear localization signal from the second zinc-finger of orphan nuclear receptor TR2. J Endocrinol 159:53-60
Lee, C H; Chinpaisal, C; Wei, L N (1998) A novel nuclear receptor heterodimerization pathway mediated by orphan receptors TR2 and TR4. J Biol Chem 273:25209-15
Chinpaisal, C; Lee, C H; Wei, L N (1998) Mechanisms of the mouse orphan nuclear receptor TR2-11-mediated gene suppression. J Biol Chem 273:18077-85
Lee, C H; Chinpaisal, C; Wei, L N (1998) Cloning and characterization of mouse RIP140, a corepressor for nuclear orphan receptor TR2. Mol Cell Biol 18:6745-55
Chinpaisal, C; Chang, L; Hu, X et al. (1997) The orphan nuclear receptor TR2 suppresses a DR4 hormone response element of the mouse CRABP-I gene promoter. Biochemistry 36:14088-95
Chang, L; Wei, L N (1997) Characterization of a negative response DNA element in the upstream region of the cellular retinoic acid-binding protein-I gene of the mouse. J Biol Chem 272:10144-50
Wei, L N (1997) Transgenic animals as new approaches in pharmacological studies. Annu Rev Pharmacol Toxicol 37:119-41
Lee, C H; Chang, L; Wei, L N (1997) Distinct expression patterns and biological activities of two isoforms of the mouse orphan receptor TR2. J Endocrinol 152:245-55
Wei, L N; Lee, C H; Filipcik, P et al. (1997) Regulation of the mouse cellular retinoic acid-binding protein-I gene by thyroid hormone and retinoids in transgenic mouse embryos and P19 cells. J Endocrinol 155:35-46

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