ChIP assays were performed mainly as previously described (45). Briefly, kidney tissues were minced finely and fixed with 1% formaldehyde at room temperature (RT) for 10 min. Cross-linking was quenched with 150 mM glycine at RT for 5 min. Nuclei were harvested and chromatin were fragmented to a size range of 200 to 500 bp with 25U benzonase (Millipore, 70664) for 15 min at RT. IP was performed using 2 μg of the Pol II antibody (Cell Signaling Technology, 14958). Purified DNA was sequenced on the BGISEQ-500 platform. The quality control of ChIP-seq data was performed by FastQC software. Clean reads were mapped to reference genome (GRCm38/mm10) using Bowtie2. Promoter region was defined as ±300 bp around the transcription start site (TSS). Gene body region was defined as +300 bp from the TSS to +3000 bp past the transcription termination site (TTS). Reads were counted using BEDtools software. PI was calculated using R-3.4.3.