Ancestralization of the modern human aryl hydrocarbon receptor by genome editing

The aryl hydrocarbon receptor (AHR) is a transcription factor that upon binding ligands induces the expression of cytochrome P450 genes, which encode enzymes that metabolize aromatic hydrocarbons. The AHR carries an amino acid substitution at position 381 in all present-day humans that occurred after the divergence of modern humans from Neandertals and Denisovans. Here, we use genome editing to revert position 381 back to the ancestral state in human cells. Cells were treated with ligands for 4 h followed by RNA extraction and RNA-Seq. Comparative gene expression profiling analysis of RNA-seq data for H9 hESC with ancestralized AHR and modern human wild type controls. Cells treated with 50 nM benzo(a)pyrene, 100 nM kynurenic acid, 10 nM indirubin or 5 µM CH-223191 for 4 h. 6 replicates per genotype and treatment.

芳基烃受体（aryl hydrocarbon receptor, AHR）是一种转录因子，当其结合配体后，会诱导编码芳香烃代谢酶的细胞色素P450基因的表达。现存人类的AHR在381位氨基酸位点存在一处氨基酸替换，该变异发生在现代人类与尼安德特人（Neandertals）、丹尼索瓦人（Denisovans）分化之后。本研究利用基因组编辑技术，将人类细胞中AHR的381位氨基酸回复至祖先状态。随后用配体处理细胞4小时，再提取RNA并进行RNA测序（RNA-Seq）。对携带祖先型AHR的H9人胚胎干细胞（H9 hESC）与现代人类野生型对照的RNA-seq数据进行比较基因表达谱分析。实验所用配体包括50 nM苯并(a)芘（benzo(a)pyrene）、100 nM犬尿烯酸（kynurenic acid）、10 nM靛玉红（indirubin）以及5 µM CH-223191，所有处理的孵育时长均为4小时。每种基因型与处理组合均设置6次生物学重复。