Fig. 4.

Identification of KRAB-ZFPs targeting human PBS sequences. (A) Human ERVs and their PBS sequences. The circles representing each type of PBS in the human genome are sized (area) according to their relative abundance among all PBS loci. (B) Histogram of the average human ZNF peak numbers per PBS from an analysis of public human ZNF ChIP-seq data (22, 23). (C) Ranking based on the numbers of each ZNF ChIP-seq peaks for each PBS type (Upper), and the consensus motif sequences of ZNFs and PBS loci (Lower). (D) Relative luciferase activity of HEK293T cells overexpressing candidate ZNFs individually, alongside plasmids for SV40 promoter–driven luciferase reporters that contain the corresponding PBS. t test: Error bars indicate SD; **P < 0.01, ***P < 0.001, ****P < 0.0001, ns (no significant), P > 0.05; n = 3.