scholarly journals Structural studies of human basement-membrane collagen with the use of a monoclonal antibody

1985 ◽  
Vol 227 (1) ◽  
pp. 217-222 ◽  
Author(s):  
H Dieringer ◽  
D W Hollister ◽  
R W Glanville ◽  
L Y Sakai ◽  
K Kühn
Keyword(s):  
Monoclonal Antibody ◽  
Basement Membrane ◽  
Type Iv Collagen ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Type Iv ◽  
Structural Probe ◽  
Basement Membrane Collagen ◽  
Antigen Antibody ◽  
Membrane Collagen

A monoclonal antibody monospecific for human type IV collagen was used as a structural probe to examine aspects of the macromolecular organization of basement-membrane collagen. Electron-microscopic observation of rotary-shadowed antigen-antibody complexes demonstrated a unique binding site for the antibody 55 +/- 6 nm distant from the 7S cross-linking region of tetrameric type IV collagen. This observation allowed a series of studies that showed: (1) the localization of an intramolecular disulphide bridge within the helical domain of the molecule, (2) the alignment of major peptic-digest fragments of the alpha 1 (IV) chain, and (3) confirmation of the postulated antiparallel arrangement of individual molecules within type IV collagen tetramers.

scholarly journals Immunohistochemical evidence for the intracellular formation of basement membrane collagen (type IV) in developing tissues.

1980 ◽  
Vol 28 (12) ◽  
pp. 1267-1274 ◽  
Author(s):  
G W Laurie ◽  
C P Leblond ◽  
I Cournil ◽  
G R Martin
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Early Stage ◽  
Basement Membranes ◽  
Incisor Tooth ◽  
Rat Incisor ◽  
Type Iv ◽  
Stage Of Development ◽  
Basement Membrane Collagen ◽  
Membrane Collagen

Antibodies to type IV collagen obtained from the basement membrane of the mouse EHS tumor were incubated with sections of rat incisor teeth and other tissues for immunostaining by direct or indirect methods. In all locations, the immunostaining was pronounced in basement membranes in which it was restricted to the "basal lamina" layer, from which "bridges" often extended to nearby basal laminae. Usually no immunostaining was detectable in the cells associated with the basement membranes. However, examination of the capillaries at the posterior extremity of the rat incisor tooth, where tissues are at an early stage of development, showed immunostaining not only of the basement membrane, but also of the endothelial cells. The staining was localized in rough endoplasmic reticulum cisternae, some Golgi saccules and their peripheral distensions, and structures believed to be secretory granules. These findings suggest that the synthesis of type IV collagen proceeds along the classical secretory pathways through rough endoplasmic reticulum and Golgi apparatus. At the same time, immunostaining was usually lacking in the cells of the capillaries that had migrated about 2 mm away from the posterior end of the incisor tooth and also in the cells of most other tissues examined, even though the associated basal laminae were reactive. It is, therefore, presumed that the production of type IV collagen may be high in cells at an early stage of development and that any later production and turnover of basement membrane collagen can only be minimal.

scholarly journals Cross-linking in type IV collagen

1984 ◽  
Vol 218 (3) ◽  
pp. 713-723 ◽  
Author(s):  
A J Bailey ◽  
T J Sims ◽  
N Light
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Collagen Molecule ◽  
Cross Linking ◽  
Type Iv ◽  
Long Form ◽  
Basement Membrane Collagen ◽  
Cross Links ◽  
Membrane Collagen ◽  
Salt Fractionation

Type IV collagen could not be extracted from human placenta using 6M-urea containing 10mM-dithiothreitol, indicating that the type IV molecule is stabilized within the basement membrane by covalent cross-links. However, various forms of type IV collagen molecule were extractable by means of increasingly severe proteolytic conditions. Type IV collagen tetramers (‘spiders’) lacking only the C-terminal globular region (NC1) were further digested to the ‘long-form’ 7S fragment and an assortment of helical rod-like molecules derived from the ‘leg’ region. These molecules were separated by salt fractionation and examined by rotary-shadowing electron microscopy. Isolation of these fractions from placenta which had been reduced with NaB3H4 revealed that both the 7S (N-terminal) and C-terminal regions contained significant proportions of reducible lysine-derived cross-links. These cross-links were shown to be exclusively the stable oxo-imine hydroxylysino-5-oxonorleucine. The number of the cross-links per molecule was significantly lower than might be expected in order to fully stabilize the molecule. These results suggest that the keto-imine cross-links in type IV collagen have been stabilized in part by conversion into an unknown non-reducible form, although a sensitive immunoassay failed to show the presence of any pyridinoline. Comparison with the fibrous collagen from placenta suggested that the rate of this conversion is much greater in basement-membrane collagen.

scholarly journals Monoclonal antibodies against chicken type IV and V collagens: electron microscopic mapping of the epitopes after rotary shadowing.

1984 ◽  
Vol 98 (5) ◽  
pp. 1637-1644 ◽  
Author(s):  
R Mayne ◽  
H Wiedemann ◽  
M H Irwin ◽  
R D Sanderson ◽  
J M Fitch ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cleavage Site ◽  
Type Iv Collagen ◽  
Collagen Molecule ◽  
Electron Microscopic ◽  
Type V Collagen ◽  
Type Iv ◽  
Type V ◽  
Rotary Shadowing

The location of the epitopes for monoclonal antibodies against chicken type IV and type V collagens were directly determined in the electron microscope after rotary shadowing of antibody/collagen mixtures. Three monoclonal antibodies against type IV collagen were examined, each one of which was previously demonstrated to be specific for only one of the three pepsin-resistant fragments of the molecule. The three native fragments were designated (F1)2F2, F3, and 7S, and the antibodies that specifically recognize each fragment were called, respectively, IA8 , IIB12 , and ID2 . By electron microscopy, monoclonal antibody IA8 recognized an epitope located in the center of fragment (F1)2F2 and in tetramers of type IV collagen at a distance of 288 nm from the 7S domain, the region of overlap of four type IV molecules. Monoclonal antibody IIB12 , in contrast, recognized an epitope located only 73 nm from the 7S domain. This result therefore provides direct visual evidence that the F3 fragment is located closest to the 7S domain and the order of the fragments must be 7S-F3-(F1)2F2. The epitope for antibody ID2 was located in the overlap region of the 7S domain, and often several antibody molecules were observed to binding to a single 7S domain. The high frequency with which antibody molecules were observed to bind to fragments of type IV collagen suggests that there is a single population of type IV molecules of chain organization [alpha 1(IV)]2 alpha 2(IV), and that four identical molecules must form a tetramer that is joined in an antiparallel manner at the 7S domain. The monoclonal antibodies against type V collagen, called AB12 and DH2 , were both found to recognize epitopes close to one another, the epitopes being located 45-48 nm from one end of the type V collagen molecule. The significance of this result still remains uncertain, but suggests that this site is probably highly immunoreactive. It may also be related to the specific cleavage site of type V collagen by selected metalloproteinases and by alpha-thrombin. This cleavage site is also known to be located close to one end of the type V molecule.

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