Microfibril-associated glycoprotein-1 and fibrillin-2 are associated with tropoelastin deposition in vitro.
Elastic system fibers consist of microfibrils and tropoelastin. During development, microfibrils act as a template on which tropoelastin is deposited. Microfibril-associated glycoprotein-1 (MAGP-1) and fibrillin-2, the major components of microfibrils, provide the likely template for tropoelastin deposition. In this study, we used the RNA interference (RNAi) technique to establish MAGP-1 and fibrillin-2 gene-specific knock-downs individually in elastin-producing cells (human gingival fibroblasts). We then examined the extracellular deposition of tropoelastin by western blotting. These two genes were specifically suppressed to < 30% of the control level, and this was responsible for the diminution of tropoelastin deposition. An immunofluorescence study also confirmed that RNAi-mediated down-regulation of MAGP-1 or fibrillin-2 led to the loss of tropoelastin immunoreactivity. These results suggest that MAGP-1 and fibrillin-2 are, directly or indirectly, associated with the extracellular deposition of tropoelastin during elastic fiber formation in human gingival fibroblasts in vitro.
Tsuruga
Eichi
E
Department of Oral Anatomy, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293, Japan. tsuru@hoku-iryo-u.ac.jp
Yajima
Toshihiko
T
Irie
Kazuharu
K
D002478:Cells, Cultured; D003285:Contractile Proteins / Q000235:genetics / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D000071840:Fibrillin-2; D000071837:Fibrillins; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D005881:Gingiva / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D020894:Microfibrils / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D000072260:RNA Splicing Factors; D034741:RNA, Small Interfering / Q000235:genetics; D014333:Tropoelastin / Q000378:metabolism*
D003285:Contractile Proteins; D016326:Extracellular Matrix Proteins; C000605723:FBN2 protein, human; D000071840:Fibrillin-2; D000071837:Fibrillins; D008840:Microfilament Proteins; D000072260:RNA Splicing Factors; D034741:RNA, Small Interfering; D014333:Tropoelastin; C016598:microfibrillar protein