A new extracellular matrix molecule, linkin, has been found in association with a microthread-like filamentous network beneath the basement membrane of all stratified epithelia tested. Direct connections of the microthread- like network can be observed with the lamina densa, collagen fibers, anchoring fibrils and elastic microfibril bundles. The association with collagen fibers appears specific since linkin occurs at regular periodic sites along the fiber.l Linkin can be identified in extracts of human skin as 73-80 kD glycoproteins by Western immunoblots using a mouse monoclonal antibody, B3a. Linkin is synthesized by human skin fibroblasts and secreted into the medium as 80, 87, and 180 kD proteins. As a prelude to the actual purification of linkin, studies will be undertaken to develop reliable assay systems for linkin, determine its solubility properties,l carbohydrate content, maximize tissue extraction and fibroblast synthesis of linkin, and determine the relationship of the immunoprecipitated linkin polypeptides. Purification will be done employing antibody affinity chromatography and/or biophysical methods. Once purified linkin will be further characterized by amino acid analysis and sequencing, peptide mapping and rotary shadowing studies of molecular size and shape. We will also attempt to isolate, clone and sequence the linkin gene from human skin fibroblast cDNA libraries. Self-assembly of linkin will be evaluated biochemically and by rotary shadowing in an attempt to reconstitute the microthread-like filamentous structures seen in vivo. Since multiple interactions are suggested by the connections of linkin-associated microthread-like filaments with other structures, interactions of linkin with other matrix molecules will be examined by double labeling immunoelectron microscopy, rotary shadowing and binding studies. The presence of linkin in early fetal skin development and in wound healing in adult skin suggest a role of linkin in these biological events. We will also examine a possible role of linkin in pathologic processes involving the skin such as lupus erythematosus and the inherited blistering disease, epidermolysis bullosa dystrophica.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AR010546-33
Application #
2700208
Study Section
Special Emphasis Panel (NSS)
Project Start
1977-05-01
Project End
2000-04-30
Budget Start
1998-05-01
Budget End
1999-04-30
Support Year
33
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Dermatology
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Jones, D A; Hunt 3rd, S W; Prisayanh, P S et al. (1995) Immunodominant autoepitopes of type VII collagen are short, paired peptide sequences within the fibronectin type III homology region of the noncollagenous (NC1) domain. J Invest Dermatol 104:231-5
Gammon, W R; Briggaman, R A (1993) Epidermolysis bullosa acquisita and bullous systemic lupus erythematosus. Diseases of autoimmunity to type VII collagen. Dermatol Clin 11:535-47
Gammon, W R; Briggaman, R A (1993) Bullous SLE: a phenotypically distinctive but immunologically heterogeneous bullous disorder. J Invest Dermatol 100:28S-34S
Gammon, W R; Murrell, D F; Jenison, M W et al. (1993) Autoantibodies to type VII collagen recognize epitopes in a fibronectin-like region of the noncollagenous (NC1) domain. J Invest Dermatol 100:618-22
Gammon, W R; Abernethy, M L; Padilla, K M et al. (1992) Noncollagenous (NC1) domain of collagen VII resembles multidomain adhesion proteins involved in tissue-specific organization of extracellular matrix. J Invest Dermatol 99:691-6
Gammon, W R; Fine, J D; Forbes, M et al. (1992) Immunofluorescence on split skin for the detection and differentiation of basement membrane zone autoantibodies. J Am Acad Dermatol 27:79-87
Woodley, D T; Yamauchi, M; Wynn, K C et al. (1991) Collagen telopeptides (cross-linking sites) play a role in collagen gel lattice contraction. J Invest Dermatol 97:580-5
Gammon, W R; Kowalewski, C; Chorzelski, T P et al. (1990) Direct immunofluorescence studies of sodium chloride-separated skin in the differential diagnosis of bullous pemphigoid and epidermolysis bullosa acquisita. J Am Acad Dermatol 22:664-70
Woodley, D T; Briggaman, R A; Herzog, S R et al. (1990) Characterization of ""neo-dermis"" formation beneath cultured human epidermal autografts transplanted on muscle fascia. J Invest Dermatol 95:20-6
Rusenko, K W; Gammon, W R; Fine, J D et al. (1989) The carboxyl-terminal domain of type VII collagen is present at the basement membrane in recessive dystrophic epidermolysis bullosa. J Invest Dermatol 92:623-7

Showing the most recent 10 out of 12 publications