Published online before print May 29, 2008, doi: 10.1161/CIRCRESAHA.108.177436
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2008 American Heart Association, Inc.
Molecular Medicine |
Smooth Muscle Expression of Lipoma Preferred Partner Is Mediated by an Alternative Intronic Promoter That Is Regulated by Serum Response Factor/Myocardin
From the Wallenberg Laboratory (M.M.R.P., H.L., E.L., P.W., E.A., S.B., E.M., S.N., P.L.), Sahlgrenska University Hospital, Göteborg, Sweden; Institute of Biomedicine (E.L., P.W., P.L.), Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, University of Göteborg, Göteborg, Sweden; and Interfaculty Institute for Cell Biology (M.A., D.H., A.N.), Tuebingen University, Germany. Present address for M.M.R.P.: Department of Human Genetics, University of Leuven, Belgium. Present address for H.L.: Pacific Vascular Research Laboratory, Department of Surgery, University of California, San Francisco. Present address for S.B.: Division of Vascular Surgery, University of Cologne, Germany. Present address for S.N.: Computational Biology Center, Memorial Sloan-Kettering Cancer Center, New York.
Correspondence to Per Lindahl, Wallenberg Laboratory of Cardiovascular Research, Bruna Stråket 16, Sahlgrenska University Hospital, SE-41345 Göteborg, Sweden. E-mail Per.Lindahl{at}wlab.gu.se
Lipoma preferred partner (LPP) was recently recognized as a smooth muscle marker that plays a role in smooth muscle cell migration. In this report, we focus on the transcriptional regulation of the LPP gene. In particular, we investigate whether LPP is directly regulated by serum response factor (SRF). We show that the LPP gene contains 3 evolutionarily conserved CArG boxes and that 1 of these is part of an alternative promoter in intron 2. Quantitative RT-PCR shows that this alternative promoter directs transcription specifically to smooth muscle containing tissues in vivo. By using chromatin immunoprecipitation, we demonstrate that 2 of the CArG boxes, including the promoter-associated CArG box, bind to endogenous SRF in cultured aortic smooth muscle cells. Electrophoretic mobility-shift assays show that the conserved CArG boxes bind SRF in vitro. In reporter experiments, we show that the alternative promoter has transcriptional capacity that is dependent on SRF/myocardin and that the promoter associated CArG box is required for that activity. Finally, we show by quantitative RT-PCR that the alternative promoter is strongly downregulated in SRF-deficient embryonic stem cells and in smooth muscle tissues derived from conditional SRF knockout mice. Collectively, our data demonstrate that expression of LPP in smooth muscle is mediated by an alternative promoter that is regulated by SRF/myocardin.
Key Words: smooth muscle • transcriptional regulation • serum response factor
Related Article:
Circ. Res. 2008 103: 13-15.
This article has been cited by other articles:
 |
|
 |
|
  G. Perot, J. Derre, J.-M. Coindre, F. Tirode, C. Lucchesi, O. Mariani, L. Gibault, L. Guillou, P. Terrier, and A. Aurias Strong Smooth Muscle Differentiation Is Dependent on Myocardin Gene Amplification in Most Human Retroperitoneal Leiomyosarcomas Cancer Res., March 15, 2009; 69(6): 2269 - 2278. [Abstract] [Full Text] [PDF]
|
|