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Cloning, Expression, and Regulation of Bovine Cellular Retinoic Acid-binding Protein-II (CRABP-II) during Adipogenesis |
Young Hee Jeong, Sang Mi Lee, Hye-Min Kim, Hyo Young Park, Duhak Yoon, Seung Ju Moon, Akemi Hosoda, Dong-Ho Kim, Shigeru Saeki, Man-Jong Kang* |
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Correspondence:
Man-Jong Kang, |
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Abstract |
The mammalian cellular retinoic acid-binding proteins, CRABP-I and CRABP-II, bind retinoic acid which acts as an inducer of differentiation in several biological systems. To investigate a possible role for CRABP-II in bovine adipogenesis, we have cloned bovine CRABP-II cDNA and the coding region for CRABP-I. The predicted amino acid sequences of CRABP-II were highly conserved among several animal species (human, mouse, and rat at 97%, 93%, and 93%, respectively). The expression pattern of bovine CRABP-II was examined in greater details by applying RT-PCR to various bovine tissues. CRABP-II mRNA was expressed in most adipose-containing tissues. Moreover, the expression of CRABP-I and -II mRNA dramatically increased during the differentiation of adipocytes from bovine intramuscular fibroblast-like cells. The effects of retinoic acid on adipocyte differentiation of bovine intramuscular fibroblast-like cells were concentration-dependent. Retinoic acid activated the formation of lipid droplets at a level of 1 nM, whereas inhibition was observed at a level of 1 M. CRABP-I gene was up-regulated and CRABP-II gene down-regulated by retinoic acid during adipocyte differentiation. These results suggest that CRABPs may play an important role in the regulation of intracellular retinoic acid concentrations during adipogenesis. |
Keywords:
Bovine Adipocyte Differentiation; Lipid-binding Protein; Retinoic Acid; Retinoic Acid Receptor; Retinoid X Receptor |
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