Putative looping factor ZNF143/ZFP143 is an essential transcriptional regulator with no looping function [ChIP-seq]

Interactions between distal loci in mammalian genomes, including those involving enhancers and promoters, are thought to be a central mechanism of gene regulation in mammals, yet the protein regulators of these interactions remain largely undetermined. The zinc finger transcription factor ZNF143/ZFP143 has been strongly implicated as a factor that regulates chromatin interactions, functioning either with or without CTCF. However, ZNF143/ZFP143’s role in this process and its function with or without CTCF are not well understood. Here, we tagged both CTCF and ZNF143/ZFP143 with dual-purpose degron/imaging tags to combinatorically assess their loop function and effect on each other. We find that ZNF143/ZFP143 possesses no general looping function, and that it largely functions independently to CTCF. Instead, ZNF143/ZFP143 is an essential and highly conserved transcription factor possessing an extremely stable chromatin residence time (>20 min) that regulates an important subset of mitochondrial and ribosomal genes.