Cloning of a cDNA encoding rat intestinal fatty acid binding protein.

Abstract

Intestinal fatty acid binding protein mRNA is one of the most abundant mRNA species in the rat small intestinal epithelium. RNA We were interested in defining the structure of this protein for several reasons. (i) Its precise function in lipid metabolism is not known. Partially purified preparations of this polypeptide have been shown to bind long-chain fatty acids, having higher affinity for unsaturated compared to saturated forms (2). However, it is unclear whether this protein actually participates in cellular fatty acid transport across the intestinal mucosa (1-3) or simply represents an intracellular FABP. (ii) The rat small intestine contains another, immunologically distinct FABP termed "liver" FABP because of its initial identification in rat hepatocytes (4, 5). The structural and functional relationships between these two proteins have not been determined. The mRNAs encoding these two FABPs are the most abundant mRNA species that accumulate in the small intestinal mucosa, comprising 3.3% (liver FABP) and 2% (intestinal FABP) of translatable RNA (5). We have recently determined the complete sequence of liver FABP mRNA from an analysis of cloned cDNA (6). Liver FABP is identical to Z protein (7) and is probably the same as sterol carrier protein (8), amino azo dye-binding protein A (9), and band C (10). (iii) These small peptides could serve as a useful model system for detailing primary and secondary structural characteristics required for lipid-prQtein interactions.In this report we describe the primary structure of this protein obtained from analysis of cloned cDNA and compare the structures of both liver and intestinal FABPs. Possible functional roles played by these peptides in intestinal lipid metabolism are discussed. MATERIALS AND METHODSMale Sprague-Dawley rats (250 g) were maintained on a standard rat chow diet and fasted overnight before being sacrificed. 3H-and 35S-labeled amino acids were purchased from Amersham. Monospecific antiserum against intestinal FABP was identical to that described previously (2). This antibody does not form precipitin lines against rat liver cytosol or purified rat liver FABP on Ouchterlony plates but reacts well with intestinal FABP and intestinal cytosol (data not shown).

The mesenchymal winged helix transcription factor Fkh6 is required for the control of gastrointestinal proliferation and differentiation.

“…For the analysis of Wnt2, Wnt5a, shh, ihh, Bmp2, and Bmp4 mRNAs, antisense probes were synthesized of plasmids kindly provided by A. McMahon (Harvard University, Cambridge, MA) and B. Hogan (Vanderbilt University, Nashville, TN). The rat liver and intestinal fatty acid-binding protein probes were described previously (Gordon et al 1983;Alpers et al 1984).…”

Evidence for a Role of the Gut Hormone PYY in the Regulation of Intestinal Fatty Acid-binding Protein Transcripts in Differentiated Subpopulations of Intestinal Epithelial Cell Hybrids

“…The biological role of intestinal FABP is still largely speculative despite extensive knowledge about its binding properties, amino acid sequence, protein structure (26,27), expression pattern during development (28 -30), and localization of genetic elements that regulate regional and cell-specific patterns of expression within the gut epithelium (30). I-FABP is a likely regulator of intracellular fatty acid levels because of its involvement in the trafficking and/or metabolism of FFAs in the intestinal epithelia (31).…”

Isoforms of fatty‐acid‐binding protein in bovine heart are coded by distinct mRNA

“…A long these, some proteins are named according to the tissu :s where they are detected in greatest abundance, such as cc" .disc [2-41, hepatic [5, 61, intestinal [7] FABP and adipoc! ,e lipid-binding protein [8].…”