SERPINB2 is regulated by dynamic interactions with pause-release proteins and enhancer RNAs

Area of Science:

• Molecular Biology
• Gene Regulation
• Inflammation Research

Background:

• The SERPINB2 gene is significantly upregulated during inflammatory conditions, playing a role in cellular protection and angioedema.
• SERPINB2 protein can comprise up to 1% of total protein in monocytes under inflammatory states.

Purpose of the Study:

• To investigate the function of enhancer RNAs within the SERPIN gene complex.
• To elucidate the regulatory mechanisms involving enhancer RNAs and SERPINB2 gene expression.

Main Methods:

• Analysis of enhancer RNA expression relative to SERPINB2 mRNA.
• Promoter studies to identify proteins involved in SERPINB2 regulation, including RNA polymerase II pause factors.
• RNA immunoprecipitation to assess protein binding to enhancer RNAs.
• Gene knockdown and overexpression experiments to determine functional effects.

Main Results:

• Upstream enhancer RNAs were found to upregulate SERPINB2 and precede SERPINB2 mRNA expression.
• The pause-inducing protein NELF was identified at the SERPINB2 promoter, with its release upon LPS stimulation.
• NELF and P-TEFb (CDK9) bound to enhancer RNAs with distinct kinetics post-stimulation.
• Knockdown of enhancer RNAs impaired stimulus-induced chromatin changes, while overexpression enhanced c-JUN recruitment and SERPINB2 expression.

Conclusions:

• This study establishes the first association between enhancer RNAs and SERPINB2 regulation.
• Enhancer RNAs play a crucial role in modulating SERPINB2 expression by influencing chromatin dynamics and transcription factor recruitment.
• The findings reveal a novel mechanism where enhancer RNAs acquire binding of regulatory proteins like NELF upon cellular stimulation.