Characterization of the human Activin-A receptor type II-like kinase 1 (ACVRL1) promoter and its regulation by Sp1 Journal Article
| Authors: | Garrido-Martin, E. M.; Blanco, F. J.; Fernandez-L, A.; Langa, C.; Vary, C. P.; Lee, U. E.; Friedman, S. L.; Botella, L. M.; Bernabeu, C. |
| Article Title: | Characterization of the human Activin-A receptor type II-like kinase 1 (ACVRL1) promoter and its regulation by Sp1 |
| Abstract: | Background: Activin receptor-like kinase 1 (ALK1) is a Transforming Growth Factor-β (TGF-β) receptor type I, mainly expressed in endothelial cells that plays a pivotal role in vascular remodelling and angiogenesis. Mutations in the ALK1 gene (ACVRL1) give rise to Hereditary Haemorrhagic Telangiectasia, a dominant autosomal vascular dysplasia caused by a haploinsufficiency mechanism. In spite of its patho-physiological relevance, little is known about the transcriptional regulation of ACVRL1. Here, we have studied the different origins of ACVRL1 transcription, we have analyzed in silico its 5'-proximal promoter sequence and we have characterized the role of Sp1 in the transcriptional regulation of ACVRL1.Results: We have performed a 5'Rapid Amplification of cDNA Ends (5'RACE) of ACVRL1 transcripts, finding two new transcriptional origins, upstream of the one previously described, that give rise to a new exon undiscovered to date. The 5'-proximal promoter region of ACVRL1 (-1,035/+210) was analyzed in silico, finding that it lacks TATA/CAAT boxes, but contains a remarkably high number of GC-rich Sp1 consensus sites. In cells lacking Sp1, ACVRL1 promoter reporters did not present any significant transcriptional activity, whereas increasing concentrations of Sp1 triggered a dose-dependent stimulation of its transcription. Moreover, silencing Sp1 in HEK293T cells resulted in a marked decrease of ACVRL1 transcriptional activity. Chromatin immunoprecipitation assays demonstrated multiple Sp1 binding sites along the proximal promoter region of ACVRL1 in endothelial cells. Furthermore, demethylation of CpG islands, led to an increase in ACVRL1 transcription, whereas in vitro hypermethylation resulted in the abolishment of Sp1-dependent transcriptional activation of ACVRL1.Conclusions: Our results describe two new transcriptional start sites in ACVRL1 gene, and indicate that Sp1 is a key regulator of ACVRL1 transcription, providing new insights into the molecular mechanisms that contribute to the expression of ACVRL1 gene. Moreover, our data show that the methylation status of CpG islands markedly modulates the Sp1 regulation of ACVRL1 gene transcriptional activity. © 2010 Garrido-Martin et al; licensee BioMed Central Ltd. |
| Keywords: | controlled study; promoter region; exon; genetics; molecular genetics; protein function; mouse; animal; metabolism; animals; mice; gene amplification; gene expression; transcription initiation; protein binding; in vitro study; enzyme activity; dna methylation; enzyme regulation; transcription regulation; amino acid sequence; molecular sequence data; cell strain hek293; messenger rna; sequence alignment; 5' untranslated region; chromatin immunoprecipitation; cpg island; cpg islands; promoter regions, genetic; dog; dogs; nucleotide sequence; rat; transcription factor sp1; sp1 transcription factor; base sequence; binding site; binding sites; cattle; rats; macaca; macaca mulatta; gel mobility shift assay; transcriptional activation; concentration response; complementary dna; 5' untranslated regions; transcription initiation site; computer analysis; activin receptors, type ii; horses; demethylation; activin receptor like kinase 1; activin receptor 2; acvrl1 protein, human; consensus sequence; gc rich sequence; tata box; horse; orang utan; pongo |
| Journal Title: | BMC Molecular Biology |
| Volume: | 11 |
| ISSN: | 1471-2199 |
| Publisher: | Biomed Central Ltd |
| Date Published: | 2010-06-29 |
| Start Page: | 51 |
| Language: | English |
| DOI: | 10.1186/1471-2199-11-51 |
| PUBMED: | 20587022 |
| PROVIDER: | scopus |
| PMCID: | PMC2906440 |
| DOI/URL: | |
| Notes: | --- - "Export Date: 20 April 2011" - "Art. No.: 51" - "CODEN: BMBMC" - "Source: Scopus" |
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