Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA.
Drug Metab Dispos. 2013 Jan;41(1):132-40. doi: 10.1124/dmd.112.048736. Epub 2012 Oct 16.
Knockout mouse models targeting various cytochrome P450 (P450 or CYP) genes are valuable for determining P450's biologic functions, including roles in drug metabolism and chemical toxicity. In this study, a novel Cyp2a(4/5)bgs-null mouse model was generated, in which a 1.2-megabase pair genomic fragment containing nine Cyp genes in mouse chromosome 7 (including, sequentially, Cyp2a5, 2g1, 2b19, 2b23, 2a4, 2b9, 2b13, 2b10, and 2s1) are deleted, through Cre-mediated recombination in vivo. The resultant mouse strain was viable and fertile, without any developmental deficits or morphologic abnormalities. Deletion of the constitutive genes in the cluster was confirmed by polymerase chain reaction analysis of the genes and the mRNAs in tissues known to express each gene. The loss of this gene cluster led to significant decreases in microsomal activities toward testosterone hydroxylation in various tissues examined, including olfactory mucosa (OM), lung, liver, and brain. In addition, systemic clearance of pentobarbital was decreased in Cyp2a(4/5)bgs-null mice, as indicated by >60% increases in pentobarbital-induced sleeping time, compared with wild-type (WT) mice. This novel Cyp2a(4/5)bgs-null mouse model will be valuable for in vivo studies of drug metabolism and chemical toxicities in various tissues, including the liver, lung, brain, intestine, kidney, skin, and OM, where one or more of the targeted Cyp genes are known to be expressed in WT mice. The model will also be valuable for preparation of humanized mice that express human CYP2A6, CYP2A13, CYP2B6, or CYP2S1, and as a knockout mouse model for five non-P450 genes (Vmn1r184, Nalp9c, Nalp4a, Nalp9a, and Vmn1r185) that were also deleted.
敲除各种细胞色素 P450（P450 或 CYP）基因的小鼠模型对于确定 P450 的生物学功能非常有价值，包括在药物代谢和化学毒性中的作用。在这项研究中，通过体内 Cre 介导的重组，生成了一种新型 Cyp2a(4/5)bgs-/-小鼠模型，该模型缺失了包含小鼠染色体 7 上的 9 个 Cyp 基因（包括 Cyp2a5、2g1、2b19、2b23、2a4、2b9、2b13、2b10 和 2s1）的 1.2 兆碱基对基因组片段。所得的小鼠品系具有活力和繁殖力，没有任何发育缺陷或形态异常。通过聚合酶链反应分析组织中已知表达每个基因的基因和 mRNA，证实了该基因簇中的组成型基因缺失。该基因簇的缺失导致各种组织中检测到的睾酮羟化的微粒体活性显著降低，包括嗅黏膜（OM）、肺、肝和脑。此外，与野生型（WT）小鼠相比，Cyp2a(4/5)bgs-/-小鼠中戊巴比妥的全身清除率降低，这表明戊巴比妥诱导的睡眠时间增加了>60%。这种新型 Cyp2a(4/5)bgs-/-小鼠模型将有助于研究各种组织（包括肝、肺、脑、肠、肾、皮肤和 OM）中的药物代谢和化学毒性，其中一个或多个靶向 Cyp 基因在 WT 小鼠中表达。该模型对于制备表达人 CYP2A6、CYP2A13、CYP2B6 或 CYP2S1 的人源化小鼠以及作为缺失 5 个非 P450 基因（Vmn1r184、Nalp9c、Nalp4a、Nalp9a 和 Vmn1r185）的敲除小鼠模型也很有价值。
