Open chromatin mapping identifies transcriptional networks regulating human epididymis epithelial function

Area of Science:

• Reproductive Biology
• Molecular Endocrinology
• Genetics

Background:

• The epididymis epithelium is vital for sperm maturation, requiring coordinated gene expression.
• Transcription factors regulate gene expression, but their specific roles in the epididymis are not fully understood.
• Paired box 2 (PAX2) is a known regulator in urogenital development, but its function in the epididymis is unexplored.

Purpose of the Study:

• To investigate the role of PAX2 in the human epididymis epithelial (HEE) cell line.
• To identify genes regulated by PAX2 in the epididymis epithelium.
• To uncover novel PAX2 targets involved in male reproductive tract function.

Main Methods:

• Genome-wide chromatin accessibility mapping (DNase-seq) in primary HEE and immortalized REP cells.
• In silico analysis to identify over-represented transcription factor-binding sites (TFBS), including PAX2 motifs.
• RNA sequencing (RNA-seq) after siRNA-mediated PAX2 depletion in REP cells to identify differentially expressed genes.

Main Results:

• PAX2-binding motifs were identified in open chromatin regions of both primary HEE and REP cells.
• Depletion of PAX2 in REP cells led to significant differential expression of 3135 transcripts.
• Novel PAX2 target genes with predicted functions in the epididymis epithelium were identified.

Conclusions:

• PAX2 is a significant transcriptional regulator in the epididymis epithelium.
• PAX2 regulates numerous genes involved in epididymis function and sperm maturation.
• This study provides new insights into the molecular mechanisms of male reproductive tract development and function.