Carnitine palmitoyltransferase I gene in Synechogobius hasta: Cloning, mRNA expression and transcriptional regulation by insulin in vitro

We cloned seven complete CPT I cDNA sequences (CPT alpha 1a-1a, CPT I alpha 1a-1b, CPT I alpha 1a-1c, CPT I alpha 1a-2, CPT I alpha 2a, CPT I alpha 2b1a, CPT I beta) and a partial cDNA sequence (CPT I alpha 2b1b) from Synechogobius hasta. Phylogenetic analysis shows that there are four CPT I duplications in S. hasta, CPT I duplication resulting in CPT I alpha. and CPT I beta, CPT I alpha duplication producing CPT I alpha 1 and CPT I alpha 2, CPT I alpha 2 duplication generating CPT I alpha 2a and CPT I alpha 2b, and CPT I alpha 2b duplication creating CPT I alpha 2b1a and CPT I alpha 2b1b. Alternative splicing of CPT I alpha 1a results in the generation of four CPT I isoforms, CPT I alpha 1a-1a, CPT I alpha 1a-1b, CPT I alpha 1a-1c and CPT I alpha 1a-2. Five CPT I transcripts (CPT I alpha 1a, CPT I alpha 2a, CPT I alpha 2b1a, CPT I alpha 2b1b and CPT I beta) mRNAs are expressed in a wide range of tissues, but their abundance of each CPT I mRNA shows the tissue-dependent expression patterns. Insulin incubation significantly reduces the mRNA expression of CPT I alpha 1a and CPT I alpha 2a, but not other transcripts in hepatocytes of S. hasta. For the first time, our study demonstrates CPT I alpha 2b duplication and CPT I alpha 1a alternative splicing in fish at transcriptional level, and the CPT I mRNAs are differentially regulated by insulin in vitro, suggesting that four CPT I isoforms may play different physiological roles during insulin signaling. (c) 2015 Elsevier B.V. All rights reserved.