Transcriptional and epigenetic effects of deleting large regions, alone or in combination, from their natural context in the chicken Ig-β gene.

Abstract Previously, we used homologous recombination to delete six groups of cell-type-specific DNase I hypersensitive sites (DHSs), potential transcriptional and epigenetic regulators, scattered in and around the Ig-β gene from their natural context in B-lymphocyte-derived chicken DT40 cells. Simultaneous deletion of all six groups completely shut down transcription and epigenetic regulation of the Ig-β gene; therefore, the cooperation of the scattered regulatory regions was essential for transcription and epigenetic regulation. In this study, we regrouped the cell-type-specific DHSs of Ig-β, those in the original six deletions and three additional ones, into three larger regional groups—the long upstream region, the intron, and the long downstream region—and deleted these groups individually or in combination. Combinatorial deletion of all three regional groups decreased Ig-β mRNA levels to 0.4% of the control, which was significantly higher than