van der Leij F R, Takens J, van der Veen A Y, Terpstra P, Kuipers J R
Department of Pediatrics, Groningen Utrecht Institute for Drug Exploration (GUIDE), Groningen University, The Netherlands.
Biochim Biophys Acta. 1997 May 30;1352(2):123-8. doi: 10.1016/s0167-4781(97)00037-7.
We isolated and sequenced cDNA and genomic DNA fragments of the human CPT1B gene, encoding muscle type camitine palmitoyltransferase I. A recombinant P1 phage containing CPT1B was mapped to chromosome 22qter by fluorescent in situ hybridization. This finding supports the concept that 'liver type' and 'muscle type' isoforms of CPT I are encoded by different loci at separate chromosomal positions. Analysis of CPT1B cDNA sequences revealed the presence of an untranslated 5' exon and differential processing of introns 13 and 19. The alternative splicing of intron 13 causes an in-frame deletion leading to a 10 amino acid residues smaller protein. Using different splice acceptor sites, intron 19 is spliced in the majority of cases, but 4 out of 14 sequenced CPT1B 3' cDNA clones contain part of intron 19 in stead of exon 20. We found that differential polyadenylation is the mechanism behind the existence of these alternative 3' CPT1B mRNA forms.
我们分离并测序了编码肌肉型肉碱棕榈酰转移酶I的人CPT1B基因的cDNA和基因组DNA片段。通过荧光原位杂交将含有CPT1B的重组P1噬菌体定位于22号染色体qter。这一发现支持了CPT I的“肝型”和“肌肉型”同工型由位于不同染色体位置的不同基因座编码的概念。对CPT1B cDNA序列的分析揭示了一个未翻译的5'外显子的存在以及内含子13和19的差异加工。内含子13的可变剪接导致框内缺失，产生一个小10个氨基酸残基的蛋白质。在大多数情况下，内含子19使用不同的剪接受体位点进行剪接，但在14个测序的CPT1B 3' cDNA克隆中有4个含有内含子19的一部分而非外显子20。我们发现差异聚腺苷酸化是这些CPT1B 3' mRNA替代形式存在的机制。
