SRF Co-factors Control the Balance between Cell Proliferation and Contractility

Area of Science:

• Molecular Biology
• Cell Biology
• Gene Regulation

Background:

• Ternary complex factors (TCFs) partner with serum response factor (SRF) to drive gene transcription in response to mitogens.
• The precise role and broader functional impact of TCFs in immediate-early gene responses remain incompletely understood.

Purpose of the Study:

• To elucidate the functional significance of TCFs in regulating gene transcription and cell proliferation.
• To investigate the interplay between TCFs, SRF, and MRTFs in controlling gene expression programs.

Main Methods:

• CRISPR-Cas9 mediated TCF inactivation in mouse embryonic fibroblasts (MEFs).
• Chromatin immunoprecipitation sequencing (ChIP-seq) for SRF.
• Hi-C for genome-wide interaction analysis.
• Analysis of TPA-inducible gene transcription and cell proliferation.

Main Results:

• TCF inactivation inhibited over 60% of TPA-inducible genes and impaired MEF proliferation.
• Over 700 direct SRF target genes were identified as TCF-dependent, involved in signaling, transcription, and proliferation.
• TCFs antagonize MRTF-mediated SRF target gene expression by competing for SRF binding.
• TCF-deficient MEFs displayed hypercontractile and pro-invasive phenotypes.

Conclusions:

• Competition between TCFs and MRTFs for SRF binding is a critical determinant of gene expression.
• This competition balances opposing cellular programs, including proliferation and cytoskeletal contractility.
• TCFs play a vital role in regulating gene transcription, cell proliferation, and cellular behavior.