RPA1 binding to NRF2 switches ARE-dependent transcriptional activation to ARE-NRE-dependent repression

Area of Science:

• Molecular Biology
• Cellular Biology
• Gene Regulation

Background:

• Nuclear factor erythroid 2-related factor 2 (NRF2) is known to activate gene transcription by binding to antioxidant response elements (AREs) with small musculoaponeurotic fibrosarcoma proteins (sMAFs).
• The role of NRF2 in transcriptional repression has not been previously reported.

Purpose of the Study:

• To investigate and characterize a novel mechanism of NRF2-mediated gene repression.
• To identify the DNA elements and protein interactions involved in NRF2-dependent transcriptional repression.

Main Methods:

• Identification of a novel DNA sequence, the NRF2-replication protein A1 (RPA1) element (NRE), flanking the ARE.
• Demonstration of RPA1 competing with sMAF for NRF2 binding, forming an NRF2-RPA1 complex.
• Genome-wide in silico and RNA-seq analyses to identify NRF2-RPA1-ARE-NRE regulated genes.
• Preclinical models of inflammatory lung injury to assess the role of NRF2-mediated repression in vivo.

Main Results:

• A novel NRF2-mediated gene repression mechanism involving the NRF2-RPA1-ARE-NRE complex was described.
• This complex negatively regulates a broad range of genes with diverse functions, indicating a fundamental cellular process.
• Repression of MYLK (myosin light chain kinase) by this complex was shown to disrupt vascular integrity in inflammatory lung injury models.

Conclusions:

• NRF2 possesses a previously unrecognized gene-suppressive function mediated by the NRF2-RPA1-ARE-NRE complex.
• This mechanism highlights a fundamental aspect of gene regulation with broad implications in physiological and pathological conditions.
• The findings underscore the translational significance of NRF2-mediated transcriptional repression, particularly in inflammatory diseases.