Data_Sheet_1_Sequencing of the Canine Cytochrome P450 CYP2C41 Gene and Genotyping of Its Polymorphic Occurrence in 36 Dog Breeds.pdf

Cytochrome P450 (CYP) drug metabolizing enzymes play an important role in efficient drug metabolism and elimination. Many CYPs are polymorphic and, thereby, drug metabolism can vary between individuals. In the case of canine CYP2C41, gene polymorphism was identified. However, as the first available canine genome sequences all were CYP2C41 negative, this polymorphism could not be clarified at the genomic level. The present study provides an exact characterization of the CYP2C41 gene deletion polymorphism at the genomic level and presents a PCR-based genotyping method that was used for CYP2C41 genotyping of 1,089 individual subjects from 36 different dog breeds. None of the Bearded Collie, Bernese Mountain, Boxer, Briard, French Bulldog or Irish Wolfhound subjects had the CYP2C41 gene in their genomes. In contrast, in the Chinese Char-Pei, Siberian Husky, Schapendoes and Kangal breeds, the CYP2C41 allele frequency was very high, with values of 67, 57, 43, and 34%, respectively. Interestingly, the site of gene deletion was identical for all CYP2C41 negative dogs, and all CYP2C41 positive dogs showed highly homologous sequence domains upstream and downstream from the CYP2C41 gene. CYP2C41 genotyping can now be routinely used in future pharmacokinetic studies in canines, in order to identify genetically-based poor or extensive drug metabolizers. This, together with more extensive in vitro drug screening for CYP2C41 substrates will help to determine the clinical relevance of CYP2C41, and to optimize drug treatment. Although the relative abundance of the CYP2C41 protein in the canine liver seems to not be very high, this CYP could substantially contribute to hepatic drug metabolism in dogs expressing CYP2C41 from both alleles and, when CYP2C41 shows higher catalytic activity to a given drug than other hepatic metabolic enzymes.

细胞色素P450（Cytochrome P450, CYP）药物代谢酶在高效药物代谢与清除过程中发挥关键作用。多数CYP家族成员具有多态性，因此个体间药物代谢能力存在显著差异。以犬源CYP2C41为例，研究人员已确认其基因多态性，但由于首批公开的犬类基因组序列均不含CYP2C41，该多态性无法在基因组层面得到阐明。本研究实现了CYP2C41基因缺失多态性的精准基因组水平表征，并建立了基于聚合酶链式反应（PCR）的基因分型方法，利用该方法对36个不同犬品种的1089份个体样本进行了CYP2C41基因分型。长须牧羊犬、伯恩山犬、拳师犬、布里犬、法国斗牛犬及爱尔兰猎狼犬的所有受试个体基因组中均未携带CYP2C41基因。与之相反，中国沙皮犬、西伯利亚哈士奇、斯恰潘道斯犬与坎高犬的CYP2C41等位基因频率极高，分别为67%、57%、43%与34%。值得注意的是，所有CYP2C41阴性犬只的基因缺失位点完全一致，而所有CYP2C41阳性犬只的CYP2C41基因上下游序列域均呈现高度同源性。目前CYP2C41基因分型技术可常规应用于未来犬类药代动力学研究，以鉴别基于遗传背景的弱代谢型或强代谢型个体。结合针对CYP2C41底物的更广泛体外药物筛选工作，该技术将有助于明确CYP2C41的临床相关性，并优化犬类药物治疗方案。尽管犬肝脏中CYP2C41蛋白的相对丰度似乎并不高，但对于同时携带两个CYP2C41等位基因的个体而言，该酶可显著参与肝脏药物代谢；若针对某一特定药物，CYP2C41的催化活性高于其他肝脏代谢酶，则其代谢贡献将更为突出。