Discovery and analysis of NFE2L1's non-transcriptional activity by transcriptome sequencing in hepatocellular carcinoma HepG2 cells

Antitumor transcription activator NFE2L1 regulates redox homeostasis, protein turnover, and material metabolism, playing a crucial role in embryonic development and the specialization of tissue and organ functions. Deficiency of the NFE2L1 gene in different regions yields distinct phenotypes, suggesting that NFE2L1 may possess functions independent of its transcription factor activity. In this study, we originally discovered the non-transcription factor activity of NFE2L1 by constructing a truncated protein, NFE2L1ΔC, which lacks the 152 amino acids at the C-terminus and loses its transcription factor activity. By studying the function of the truncated NFE2L1 protein, we revealed that the suppressor effect of NFE2L1 on tumor cells does not require its transcription factor activity and nuclear localization. Then, transcriptome sequencing was performed to decipher the function of NFE2L1, and the results revealed that NFE2L1 regulated redox homeostasis, proteasome function, and antiviral and proinflammatory responses primarily through its transcriptional activation function in the nucleus. In contrast, NFE2L1’s regulation of developmental related signals, ribosome function, and canceration were closely associated with its non-transcription factor activity in the cytoplasm. In this study, the non-transcription factor activity of NFE2L1 was discovered and described for the first time, laying a foundation for both basic and applied research on NFE2L1.