A Human Accelerated Region is a Leydig cellGLI2Enhancer that Affects Male-Typical Behavior

Abstract

Human accelerated regions (HARs) are sequences that have evolved at an accelerated rate in the human lineage. Some HARs are developmental enhancers. We used a massively parallel reporter assay (MPRA) to identify HARs with enhancer activity in a mammalian testis cell line. A subset of HARs exhibited differential activity between the human and chimpanzee orthologs, representing candidates for underlying unique human male reproductive biology. We further characterized one of these candidate testis enhancers, 2xHAR.238. CRISPR/Cas9-mediated deletion in a testis cell line and mice revealed that 2xHAR.238 enhances expression of Gli2, encoding a Hedgehog pathway effector, in testis Leydig cells. 4C-seq revealed that 2xHAR.238 contacts the Gli2 promoter, consistent with enhancer function. In adult male mice, deletion of 2xHAR.238 disrupted mouse male-typical behavior and male interest in female odor. Combined, our work identifies a HAR that promotes the expression of Gli2 in Leydig cells and may have contributed to the evolution of human male reproductive biology.

Resolving the three-dimensional interactome of Human Accelerated Regions during human and chimpanzee neurodevelopment

“…HARs have been shown to drive changes in gene expression in genetically modified mouse models [12][13][14][15] , while massively parallel reporter assays (MPRAs) comparing HARs with their non-human primate orthologs have identified HARs that exhibit species-specific changes in enhancer activity [16][17][18] . Targeted perturbations and large-scale CRISPR proliferation screens have also been used to link HARs to changes in gene expression and neural stem cell phenotypes 19,20 . Another class of regulatory elements with a potential role in human brain development and evolution, known as Human Gained Enhancers (HGEs), have been identified based on increased levels of histone modifications associated with enhancer activity in the developing human brain compared to other species [21][22][23] .…”