TSHZ3 and SOX9 regulate the timing of smooth muscle cell differentiation in the ureter by reducing myocardin activity

Elise Martin; Xavier Caubit; Rannar Airik; Christine Vola; Ahmed Fatmi; Andreas Kispert; Laurent Fasano

doi:10.1371/journal.pone.0063721

TSHZ3 and SOX9 regulate the timing of smooth muscle cell differentiation in the ureter by reducing myocardin activity

PLoS One. 2013 May 6;8(5):e63721. doi: 10.1371/journal.pone.0063721. Print 2013.

Authors

Elise Martin¹, Xavier Caubit, Rannar Airik, Christine Vola, Ahmed Fatmi, Andreas Kispert, Laurent Fasano

Affiliation

¹ Aix-Marseille Université, CNRS, IBDM UMR7288, Marseille, France.

Abstract

Smooth muscle cells are of key importance for the proper functioning of different visceral organs including those of the urogenital system. In the mouse ureter, the two transcriptional regulators TSHZ3 and SOX9 are independently required for initiation of smooth muscle differentiation from uncommitted mesenchymal precursor cells. However, it has remained unclear whether TSHZ3 and SOX9 act independently or as part of a larger regulatory network. Here, we set out to characterize the molecular function of TSHZ3 in the differentiation of the ureteric mesenchyme. Using a yeast-two-hybrid screen, we identified SOX9 as an interacting protein. We show that TSHZ3 also binds to the master regulator of the smooth muscle program, MYOCD, and displaces it from the coregulator SRF, thereby disrupting the activation of smooth muscle specific genes. We found that the initiation of the expression of smooth muscle specific genes in MYOCD-positive ureteric mesenchyme coincides with the down regulation of Sox9 expression, identifying SOX9 as a possible negative regulator of smooth muscle cell differentiation. To test this hypothesis, we prolonged the expression of Sox9 in the ureteric mesenchyme in vivo. We found that Sox9 does not affect Myocd expression but significantly reduces the expression of MYOCD/SRF-dependent smooth muscle genes, suggesting that down-regulation of Sox9 is a prerequisite for MYOCD activity. We propose that the dynamic expression of Sox9 and the interaction between TSHZ3, SOX9 and MYOCD provide a mechanism that regulates the pace of progression of the myogenic program in the ureter.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cell Differentiation*
Down-Regulation
Female
Gene Expression Regulation, Developmental
HEK293 Cells
Homeodomain Proteins / chemistry
Homeodomain Proteins / physiology*
Humans
Male
Mice
Mice, Transgenic
Muscle Development
Myocytes, Smooth Muscle / physiology*
Nuclear Proteins / metabolism*
Protein Binding
Protein Interaction Domains and Motifs
SOX9 Transcription Factor / chemistry
SOX9 Transcription Factor / physiology*
Serum Response Factor / metabolism
Stem Cells / metabolism
Trans-Activators / metabolism*
Transcription, Genetic
Transcriptional Activation
Ureter / cytology*
Ureter / embryology

Substances

Homeodomain Proteins
Nuclear Proteins
SOX9 Transcription Factor
SOX9 protein, human
SRF protein, human
Serum Response Factor
TSHZ3 protein, human
Trans-Activators
myocardin

Grants and funding

Research in the laboratory of LF was supported by the Centre National de la Recherche Scientifique (CNRS) with additional funding from the Association Française contre les Myopathies (AFM, grants 12545, 13013) and the Agence Nationale de la Recherche (ANR, grant ANR-09-GENO-027-01). Work in the laboratory of AK was supported by a grant (DFG Ki728/7-1) from the Deutsche Forschungsgemeinschaft (German Research Council). E. Martin was a fellow of the AFM. Part of this work was performed using France-BioImaging infrastructure supported by the Agence Nationale de la Recherche (ANR-10-INSB-04-01, call “Investissements d'Avenir”). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.