title: Analysis of the tissue-specific expression, developmental regulation, and linkage relationships of a rodent gene encoding heart fatty acid binding protein.
abstract: The rat contains at least three homologous cytosolic proteins that bind long chain fatty acids, termed liver (L-), intestinal (I-), and heart (H-) fatty acid binding protein (FABP). I-FABP mRNA is confined to the gastrointestinal tract while L-FABP mRNA is abundantly represented in hepatocytes as well as enterocytes. We have isolated a rat heart FABP cDNA clone and determined the pattern of H-FABP mRNA accumulation in a wide variety of tissues harvested from late fetal, suckling, weaning, and adult rats. RNA blot hybridizations and primer extension analysis disclosed that the distribution of H-FABP mRNA in adult rat tissues is different from that of I- or L-FABP mRNA. H-FABP mRNA is most abundant in adult heart. This mRNA was also present in an adult slow twitch (type I) skeletal muscle (soleus, 63% of the concentration in heart), testes (28%), a fast twitch skeletal muscle (psoas, 17%), brain (10%), kidney (5%), and adrenal gland (5%). H-FABP mRNA was not detected in adult small intestine, colon, spleen, lung, or liver RNA. Distinct patterns of developmental change in H-FABP mRNA accumulation were documented in heart, placenta, brain, kidney, and testes. Myocardial H-FABP mRNA levels rise rapidly during the 48 h prior to and after birth, reaching peak levels by the early weaning period. The postnatal increase in myocardial H-FABP mRNA concentration and its relative distribution in adult fast and slow twitch skeletal muscle are consistent with its previously proposed function in facilitating mitochondrial beta-oxidation of fatty acids. However, the presence of H-FABP mRNA in brain, a tissue which does not normally significantly oxidize fatty acids in late postnatal life, suggests that H-FABP may play a wider role in fatty acid metabolism than previously realized. Mouse-hamster somatic cell hybrids were utilized to map H-FABP. Using stringencies which did not produce cross-hybridization between L-, I-, and H-FABP DNA sequences, we found at least three loci in the mouse genome, each located on different chromosomes, which reacted with our cloned H-FABP cDNA. None of these H-FABP-related loci were linked to the gene which specifies a highly homologous adipocyte-specific protein termed aP2 or to genes encoding two other members of this protein family, cellular retinol binding protein and cellular retinol binding protein II.(ABSTRACT TRUNCATED AT 400 WORDS)
mesh_terms: D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D004262:DNA Restriction Enzymes; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism; D005796:Genes; D008040:Genetic Linkage; D006321:Heart / Q000254:growth & development*; D009206:Myocardium / Q000378:metabolism; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D014018:Tissue Distribution; D014158:Transcription, Genetic
chemical_list: D002352:Carrier Proteins; C493320:Fabp1 protein, mouse; C493321:Fabp1 protein, rat; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D004247:DNA; D004262:DNA Restriction Enzymes