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- Sasaki, T, et al.
(författare)
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Expression and distribution of laminin alpha 1 and alpha 2 chains in embryonic and adult mouse tissues: An immunochemical approach
- 2002
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 275:2, s. 185-199
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Tidskriftsartikel (refereegranskat)abstract
- Protein levels, mRNA expression, and localization of laminin alpha1 and alpha2 chains in development and in adult mice were examined. Recombinant fragments were used to obtain high-titer-specific polyclonal antibodies for establishing quantitative radioimmuno-inhibition assays. This often demonstrated an abundance of alpha2 chain, but also distinct amounts of alpha1 chain for adult tissues. The highest amounts of alpha1 were found in placenta, kidney, testis, and liver and exceeded those of alpha2. All other tissue extracts showed a higher content of alpha2, which was particularly high in heart and muscle when compared to alpha1. Content of gamma1 chain, shared by most laminins, was also analyzed. This demonstrated gamma1 chain levels being equal to or moderately exceeding the sum of alpha1 and alpha2 chains, indicating that these isoforms represent the major known laminin isoforms in most adult mouse tissues so far examined. Moreover, we found good correlation between radioimmuno-inhibition data and mRNA levels of adult tissues as measured by quantitative real-time reverse transcriptase-PCR. Embryonic tissues were also analyzed by radioimmuno-inhibition assays. This demonstrated for day 11 embryos comparable amounts of alpha1 and gamma1 and a more than 25-fold lower content of alpha2. This content increased to about 10% of alpha1 in day 13 embryos. The day 18 embryo showed in heart, kidney, and liver, but not yet in brain and lung, alpha1/alpha2 chain ratios comparable to those in adult tissues. Immunostaining demonstrated alpha1 in Reichert's membrane (day 7.5), while alpha2 could not be detected before day 11.5. These data were compared with immunohistochemical localization results on several more embryonic and adult tissue sections. Our results regarding localization are consistent with those of earlier work with some notable exceptions. This was in part due to epitope masking for monoclonal antibodies commonly used in previous studies in esophagus, intestine, stomach, liver, kidney, and spleen. (C) 2002 Elsevier Science (USA).
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| 4. |
- Salmivirta, K, et al.
(författare)
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Binding of mouse nidogen-2 to basement membrane components and cells and its expression in embryonic and adult tissues suggest complementary functions of the two nidogens
- 2002
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 279:2, s. 188-201
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Tidskriftsartikel (refereegranskat)abstract
- Nidogen-1 binds several basement membrane components by well-defined, domain-specific interactions. Organ culture and gene targeting approaches suggest that a high-affinity nidogen-binding site of the laminin gamma1 chain (y1III4) is important for kidney development and for nerve guidance. Other proteins may also bind gamma1III4, although human nidogen-2 binds poorly to the mouse laminin gamma1 chain. We therefore characterized recombinant mouse nidogen-2 and its binding to basement membrane proteins and cells. Mouse nidogen-1 and -2 interacted at comparable levels with collagen IV, perlecan, and fibulin-2 and, most notably, also with laminin-1 fragments P1 and gamma1III3-5, which both contain the gamma1III4 module. In embryos, nidogen-2 mRNA was produced by mesenchyme at sites of epithelial-mesenchymal interactions, but the protein was deposited on epithelial basement membranes, as previously shown for nidogen-1. Hence, binding of both nidogens to the epithelial laminin gamma1 chain is dependent on epithelial-mesenchymal interactions. Epidermal growth factor stimulated expression of both nidogens in embryonic submandibular glands. Both nidogens were found in all studied embryonic and adult basement membranes. Nidogen-2 was more adhesive than nidogen-1 for some cell lines and was mainly mediated by alpha3beta1 and alpha6beta1 integrins as shown by antibody inhibition. These findings revealed extensive coregulation of nidogen-1 and -2 expression and much more complementary functions of the two nidogens than previously recognized. (C) 2002 Elsevier Science (USA).
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| 5. |
- Salmivirta, K., Talts, J. F., Olsson, M., Sasaki, T., Timpl, R., Ekblom, P.
(författare)
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Binding of mouse nidogen-2 to basement membrane components and cells and its expression in embryonic and adult tissues suggest complementary functions of the two nidogens
- 2002
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Ingår i: Exp Cell Res. ; 279:2, s. 188-201
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Tidskriftsartikel (refereegranskat)abstract
- Nidogen-1 binds several basement membrane components by well-defined, domain-specific interactions. Organ culture and gene targeting approaches suggest that a high-affinity nidogen- binding site of the laminin gamma1 chain (gamma1III4) is important for
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| 7. |
- Wiberg, Charlotte, et al.
(författare)
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Biglycan and decorin bind close to the n-terminal region of the collagen VI triple helix
- 2001
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:22, s. 18947-18952
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Tidskriftsartikel (refereegranskat)abstract
- The binding of native biglycan and decorin to pepsin-extracted collagen VI from human placenta was examined by solid phase assay and by measurement of surface plasmon resonance in the BIAcore(TM)2000 system. Both proteoglycans exhibited a strong affinity for collagen VI with dissociation constants (K(D)) of approximately 30 nm. Removal of the glycosaminoglycan chains by chondroitinase ABC digestion did not significantly affect binding. In coprecipitation experiments, biglycan and decorin bound to collagen VI and equally competed with the other, suggesting that biglycan and decorin bind to the same binding site on collagen VI. This was confirmed by electron microscopy after negative staining of complexes between gold-labeled proteoglycans and collagen VI, demonstrating that both biglycan and decorin bound exclusively to a domain close to the interface between the N terminus of the triple helical region and the following globular domain. In solid phase assay using recombinant collagen VI fragments, it was shown that the alpha2(VI) chain probably plays a role in the interaction.
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