Wang D, Harrison W, Buja L M, Elder F F, McMillin J B
Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston 77030, USA.
Genomics. 1998 Mar 15;48(3):314-23. doi: 10.1006/geno.1997.5184.
Carnitine palmitoyltransferase I (CPT-I) is a key enzyme involved in the regulation of fatty acid oxidation. CPT-IA and CPT-IB are isoforms of carnitine palmitoyltransferase I, of which CPT-IA is expressed in liver, kidney, fibroblasts, and heart and CPT-IB is expressed in skeletal 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 CPT-IB, only the cDNA sequence has been published. We have cloned the entire 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-IB located in a short first exon, which is a 13-bp extension to the previously published cDNA 5' sequence. The coding sequence is identical with the rat muscle cDNA. The rat CPT-IB 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 putative promoter region was identified to within 391 bp of the transcription start site. The muscle specificity of the 5' flanking region was verified by comparison of luciferase expression to that of beta-galactosidase in cardiac myocytes and in HepG2 cells.
肉碱棕榈酰转移酶I（CPT-I）是参与脂肪酸氧化调节的关键酶。CPT-IA和CPT-IB是肉碱棕榈酰转移酶I的同工型，其中CPT-IA在肝脏、肾脏、成纤维细胞和心脏中表达，CPT-IB在骨骼肌、心脏、棕色和白色脂肪细胞以及睾丸中表达。尽管人类CPT-IB的基因组DNA序列是已知的，但其转录起始位点和上游调控序列尚不清楚。对于大鼠CPT-IB，仅发表了cDNA序列。我们从Lambda fix II大鼠肾脏基因组文库中克隆了完整的大鼠CPT-IB基因。基因组结构包含19个外显子，CPT-IB的转录起始位点位于一个短的第一外显子中，该外显子是先前发表的cDNA 5'序列的13 bp延伸。编码序列与大鼠肌肉cDNA相同。大鼠CPT-IB基因包含18个内含子和19个外显子，后18个外显子与人类CPT-IB cDNA具有85%的同源性。CPT-IB定位于大鼠7号染色体q34带。在转录起始位点的391 bp范围内鉴定出一个推定的启动子区域。通过比较心肌细胞和HepG2细胞中荧光素酶表达与β-半乳糖苷酶表达，验证了5'侧翼区域的肌肉特异性。
