GENOMIC DNA-SEQUENCE, PROMOTER EXPRESSION, AND CHROMOSOMAL MAPPING OFRAT MUSCLE CARNITINE PALMITOYLTRANSFERASE-I

Carnitine palmitoyltransferase I (CPT-I) is a key enzyme involved in t he regulation of fatty acid oxidation. CPT-IA and CPT-IB are isoforms of carnitine palmitoyltransferase I, of which CPT-IA is expressed in l iver, kidney, fibroblasts, and heart and CPT-IB is expressed in skelet al muscle, heart, brown and white adipocytes, and testes. Although the genomic DNA sequence of human CPT-IB is available, the transcription start site and upstream regulatory sequences are not known. For rat CP T-LB, only the cDNA sequence has been published. We have cloned the en tire rat CPT-IB gene from a Lambda Fix II rat kidney genomic library. The genomic structure contains 19 exons, with the transcription start site for CPT-LB located in a short first exon, which is a 13-bp extens ion to the previously published cDNA 5' sequence. The coding sequence is identical with the rat muscle cDNA. The rat CPT-TS gene contains 18 introns and 19 exons, the latter 18 exons showing 85% homology to the human CPT-IB cDNA. CPT-IB maps to rat chromosome 7 at band q34. A put ative promoter region was identified to within 391 bp of the transcrip tion start site. The muscle specificity of the 5' flanking region was verified by comparison of luciferase expression to that of beta-galact osidase in cardiac myocytes and in HepG2 cells. (C) 1998 Academic Pres s.