Molecular and cellular characterization of SEL-OB/SVEP1 in osteogenic cells in vivo and in vitro.
We describe a novel human gene, named SEL-OB/SVEP1, expressed by skeletal tissues in vivo and by cultured osteogenic cells. The mRNA expression was analyzed on frozen tissues retrieved by laser-capture microscope dissection (LCM) and was detected in osteogenic tissues (periosteum and bone) but not in cartilage or skeletal muscle. The SEL-OB/SVEP1 cDNA of 11,139 bp was in silico translated into a 3574AA protein with expected molecular weight of 370 kDa. The protein is composed of multiple domains including complement control protein (CCP) modules with selectin superfamily signature; sushi and other domains, such as vWA, EGF, PTX, and HYR. Stromal osteogenic cells were analyzed for the protein expression using anti-SEL-OB/SVEP1 for immuno-precipitation and Western blot application confirm the presence of high molecular weight protein. Immuno-histochemistry and fluorescence-activated cell sorting (FACS) were applied to detect SEL-OB/SVEP1 on the surface of stromal cells. ELISA quantified the dependence of protein expression on cell density. Bioinformatic analysis of SEL-OB/SVEP1 revealed domains compositions recognized in cell surface molecules and suggested its role in cell adhesion. Analysis of mesechymal osteogenic cells' adhesion in presence of anti-SEL-OB/SVEP1 antibody demonstrated its interference with initial adhesion stages. In summary, present study describes novel SEL-OB/SVEP1 protein with a unique composition of functional domains, restricted pattern of expression in skeletal cells and demonstrated involvement in attachment of mesenchymal cells. The unusual composition of functional domains puts SEL-OB/SVEP1 in the discrete new group of membrane proteins involved in cell adhesion processes. All together makes SEL-OB/SVEP1 an attractive marker for studying the role of stromal osteogenic cells and their interactions within the bone marrow microenvironment creating a network that regulates the skeletal homeostasis.
Shur
I
I
Department of Cell and Developmental Biology, Sackler School of Medicine, Tel-Aviv University, Israel.
Socher
R
R
Hameiri
M
M
Fried
A
A
Benayahu
D
D
D000818:Animals; D001483:Base Sequence; D001854:Bone Marrow Cells / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000378:metabolism*; D051381:Rats; D017385:Sequence Homology; D017154:Stromal Cells / Q000378:metabolism
D015815:Cell Adhesion Molecules; D008565:Membrane Proteins; C508516:SVEP1 protein, human