Time series analysis of transcriptional regulation of NF‐kB targeted genes in vivo during the onset of liver regeneration

Abstract

NF‐kB is an essential beta‐scaffold transcription factor actively involved in embryonic liver development and liver regeneration. Previous studies on temporal and functional analysis of transcriptional regulatory networks in regenerating liver showed that NF‐kB is significantly activated within an hour of 70% partial hepatectomy. This NF‐kB activation is expected to lead to a broad range of functional changes in gene expression between 0 to 6 hours attributed to the transition of hepatocytes from G0 to G1 phase of cell cycle. Based on promoter analysis using our PAINT bioinformatics software, we have identified several potential NF‐kB targeted genes that are differentially regulated during this process. We validated a subset of these predictions at 21 distinct target promoters using Chromatin Immunoprecipitation followed by real‐time PCR. Our results reveal that NF‐kB binding is significantly up regulated for all of the 21 tested promoters including those of key genes such as Mt1a, Vim, Cyp4b1, iNOS, and Cebpb. These findings indicate that the increase in activity of NF‐kB is correlated with corresponding increase in binding at promoters of key genes regulated in the onset of liver regeneration. Research Support: NIH/NIAAA R21 AA016919, R01 AA018873, R01 AA008714.