EZH2 specifically regulates ISL1 during embryonic urinary tract formation.

Area of Science:

• Developmental Biology
• Genetics
• Urology

Background:

• The gene ISL1 is a known embryonic master control gene involved in genital development.
• Genetic studies identified ISL1 as a key susceptibility gene for classic bladder exstrophy (CBE).
• Previous research linked ISL1 deletion in mice to epispadias-like phenotypes.

Purpose of the Study:

• To investigate the regulatory mechanisms of ISL1 in urinary tract formation.
• To identify the role of EZH2 in ISL1 regulation and its association with CBE.
• To explore the genetic basis of classic bladder exstrophy.

Main Methods:

• Genome-wide association studies (GWAS) meta-analysis to identify significant markers near ISL1.
• In silico analysis to predict regulatory effects of genetic markers.
• Identification and characterization of a novel intragenic promoter for ISL1.
• EZH2 silencing experiments in HEK cells and CRISPR/Cas9 knockout in zebrafish.

Main Results:

• A novel ISL1 promoter region containing an EZH2 binding site was identified.
• EZH2 silencing led to reduced ISL1 expression in HEK cells.
• EZH2 knockout zebrafish larvae showed decreased ISL1 expression in the pronephric region.
• EZH2 deficient zebrafish exhibited malformed nephric ducts, suggesting a role in urinary tract development.

Conclusions:

• EZH2 is a critical regulator of ISL1 during urinary tract formation.
• Tissue-specific dysregulation of ISL1, potentially mediated by EZH2, is implicated in the pathogenesis of classic bladder exstrophy.
• This study provides novel insights into the molecular mechanisms underlying CBE.