Genetics and Genomics of SOST : Functional Analysis of Variants and Genomic Regulation in Osteoblasts

• Published in: International journal of molecular sciences Vol. 22; no. 2; p. 489
• Main Authors: Martínez-Gil, Núria, Roca-Ayats, Neus, Cozar, Mónica, Garcia-Giralt, Natàlia, Ovejero, Diana, Nogués, Xavier, Grinberg, Daniel, Balcells, Susanna
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 06-01-2021; MDPI
• Subjects: 4C-seq; Binding sites; Biomedical materials; bone; Bone density; Bone turnover; Bones; Chromosomes; Displays; Enhancers; Fractures; Functional analysis; Gene expression; Genotype & phenotype; HBM; Homeostasis; luciferase reporter assay; Mutation; Osteoblasts; Osteoporosis; Peptides; Proteins; sclerostin; SOST protein; Tata box; Transcription factors; Wnt protein; luciferase reporter assay; HBM; bone; 4C-seq; sclerostin
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22020489

encodes the sclerostin protein, which acts as a key extracellular inhibitor of the canonical Wnt pathway in bone, playing a crucial role in skeletal development and bone homeostasis. The objective of this work was to assess the functionality of two variants previously identified (the rare variant rs570754792 and the missense variant p.Val10Ile) and to investigate the physical interactors of the
proximal promoter region in bone cells. Through a promoter luciferase reporter assay we show that the minor allele of rs570754792, a variant located in the extended TATA box motif, displays a significant decrease in promoter activity. Likewise, through western blot studies of extracellular and intracellular sclerostin, we observe a reduced expression of the p.Val10Ile mutant protein. Finally, using a circular chromosome conformation capture assay (4C-seq) in 3 bone cell types (MSC, hFOB, Saos-2), we have detected physical interactions between the
proximal promoter and the
enhancer, several additional enhancers located between
and
and a distant region containing exon 18 of
. In conclusion,
presents functional regulatory and missense variants that affect its expression and displays physical contacts with far reaching genomic sequences, which may play a role in its regulation within bone cells.