Functionality of two new polymorphisms in the human renin gene enhancer region

Area of Science:

• Genetics
• Molecular Biology
• Endocrinology

Background:

• Renin production, a key step in the renin-angiotensin system, is regulated by a distal promoter enhancer element in the human gene.
• This 225 bp enhancer element (-5777 to -5552) is crucial for stimulating renin gene expression.

Purpose of the Study:

• To validate the role of the 225 bp enhancer in regulating renin gene transcription.
• To identify genetic variations within this enhancer region and assess their functional impact.
• To elucidate the full extent of the human renin gene enhancer.

Main Methods:

• Decoy experiments using the 225 bp enhancer in human choriodecidual cells to assess promoter activity.
• DNA sequencing of 70 genomic samples to identify single nucleotide polymorphisms (SNPs) in the enhancer region.
• Transfection assays with various promoter constructs containing identified SNPs to measure renin gene transcription.
• Gel mobility shift assays to identify cis-regulatory elements interacting with the -5312 SNP.

Main Results:

• The 225 bp enhancer element significantly inhibited renin gene promoter activity by 95% in decoy experiments.
• Two novel SNPs were identified at positions -5434 and -5312.
• A larger region (592 bp) encompassing the 225 bp enhancer and the -5312 SNP exhibited stronger enhancer activity.
• The -5312T variant showed a 45% increase in transcription levels compared to the -5312C variant; the -5434 variants had no significant effect.
• Specific nuclear protein interactions with the -5312 SNP region were confirmed.

Conclusions:

• The human renin gene enhancer encompasses more than the previously identified 225 bp element.
• The enhancer region extends to include the -5312 SNP, which plays a significant role in modulating renin gene transcription.
• Genetic variations within this extended enhancer region can influence renin production.