SMAD1 and SMAD5 expression is coordinately regulated by FLI1 and GATA2 during endothelial development.

Document Type

Article

Publication Date

6-1-2015

Institution/Department

Molecular Medicine; MMCRI

Journal Title

Molecular and cellular biology

MeSH Headings

Animals, Base Sequence, Cell Line, Endothelium, GATA2 Transcription Factor, Gene Expression Regulation, Developmental, Gene Knockdown Techniques, Mice, Molecular Sequence Data, Promoter Regions, Genetic, Proto-Oncogene Protein c-fli-1, Smad1 Protein, Smad5 Protein

Abstract

The bone morphogenetic protein (BMP)/SMAD signaling pathway is a critical regulator of angiogenic sprouting and is involved in vascular development in the embryo. SMAD1 and SMAD5, the core mediators of BMP signaling, are vital for this activity, yet little is known about their transcriptional regulation in endothelial cells. Here, we have integrated multispecies sequence conservation, tissue-specific chromatin, in vitro reporter assay, and in vivo transgenic data to identify and validate Smad1+63 and the Smad5 promoter as tissue-specific cis-regulatory elements that are active in the developing endothelium. The activity of these elements in the endothelium was dependent on highly conserved ETS, GATA, and E-box motifs, and chromatin immunoprecipitation showed high levels of enrichment of FLI1, GATA2, and SCL at these sites in endothelial cell lines and E11 dorsal aortas in vivo. Knockdown of FLI1 and GATA2 but not SCL reduced the expression of SMAD1 and SMAD5 in endothelial cells in vitro. In contrast, CD31(+) cKit(-) endothelial cells harvested from embryonic day 9 (E9) aorta-gonad-mesonephros (AGM) regions of GATA2 null embryos showed reduced Smad1 but not Smad5 transcript levels. This is suggestive of a degree of in vivo selection where, in the case of reduced SMAD1 levels, endothelial cells with more robust SMAD5 expression have a selective advantage.

ISSN

1098-5549

First Page

2165

Last Page

2172

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