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  • Mapping of domains in human laminin using monoclonal antibodies: localization of the neurite-promoting site. 2430984

    Monoclonal antibodies were made against a truncated form of human laminin isolated from placenta. 12 antibodies were isolated and characterized. All antibodies stained basement membranes in placenta and immunoprecipitated laminin from media of cultured choriocarcinoma cells. Three antibodies, 3E5, 4C7, and 4E10, partially blocked the neurite-promoting activity of laminin. Addition of a second antibody, goat anti-mouse IgG, caused more complete blocking of the activity. Two of the blocking antibodies, 4C7 and 4E10, reacted with epitopes within the globular domain at the end of the long arm of laminin, and the third one, 3E5, reacted at the end of the rod-like portion of the long arm adjacent to the globular domain, as shown by electron microscopy after rotary shadowing. Five nonblocking antibodies used in the same test reacted with epitopes in other domains of the molecule. Blocking antibodies 3E5 and 4E10 could be used in immunoblotting and both antibodies reacted with the same polypeptides in pepsin fragments of human laminin, the predominant polypeptides being approximately 400 kD. When a crude extract of human amnion was used as a source of intact laminin, the 4E10 antibody detected a single polypeptide of approximately 400 kD. A nonblocking antibody, 2E8, which reacted at the center of the laminin cross, reacted predominantly with a 200-kD polypeptide in human laminin fragments and exclusively with a 200-kD polypeptide in amnion extract and in rat laminin. Our results with human laminin match the results by Edgar, D., R. Timpl, and H. Thoenen, 1984, EMBO (Eur. Mol. Biol. Organ.) J., 3:1463-1468, in which the neurite-promoting activity of mouse laminin resides at the end of the long arm, which is also the site for heparin binding. However, since the active fragments of human laminin did not bind to heparin, the neurite-promoting site should be different from the heparin-binding site. Our results further suggest that the neurite-promoting site may be contained in or close to the 400-kD component of laminin.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Neural tube defects by NUAK1 and NUAK2 double mutation. 22689267

    Background: NUAK1 and NUAK2, members of the AMP-activated protein kinase family of serine/threonine kinases, are prominently expressed in neuroectoderm, but their functions in neurulation have not been elucidated. Results: NUAK1 and NUAK2 double mutants exhibited exencephaly, facial clefting, and spina bifida. Median hinge point was formed, but dorsolateral hinge point formation was not apparent in cranial neural plate; neither apical constriction nor apico-basal elongation took place efficiently in the double mutants during the 5-10-somite stages. Concomitantly, the apical concentration of phosphorylated myosin light chain 2, F-actin, and cortactin was insignificant, and development of acetylated α-tubulin-positive microtubules was poor. However, the distribution of F-actin, cortactin, Shroom3, Rho, myosin heavy chain IIB, phosphorylated myosin light chain 2, α-tubulin, γ-tubulin, or acetylated α-tubulin was apparently normal in the double mutant neuroepithelia at the 5-somite stage. Conclusions: NUAK1 and NUAK2 complementarily function in the apical constriction and apico-basal elongation that associate with the dorsolateral hinge point formation in cephalic neural plate during the 5- to 10-somite stages. In the double mutant neural plate, phosphorylated myosin light chain 2, F-actin, and cortactin did not concentrate efficiently in apical surfaces, and acetylated α-tubulin-positive microtubules did not develop significantly. Developmental Dynamics 241:1350-1364, 2012. © 2012 Wiley Periodicals, Inc.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1997
    Nombre del producto:
    Anti-Integrin β1 Antibody, clone MB1.2

  • Abnormal expression of laminin beta 1 chain in skeletal muscle of adult-onset limb-girdle muscular dystrophy. 9400354

    BACKGROUND: Laminin 2 is a major component of the basal lamina of skeletal muscle cells. It is a heterotrimer composed of 3 chains: merosin (laminin alpha 2 chain), beta 1, and gamma 1. Deficiency of merosin, with or without laminin beta 1 chain reduction, is associated with some forms of congenital muscular dystrophy. Deficient expression of laminin beta 1 chain is also associated with some cases of merosin-positive congenital muscular dystrophy. The expression of laminin 2 subunits has not been well studied in the skeletal muscle of limb-girdle muscular dystrophy (LGMD), nor has much attention been given to the significance of reduction of individual laminin 2 subunits, such as beta 1. OBJECTIVES: To examine the expression of laminin 2 subunits in skeletal muscle in patients with LGMD and to define the clinical features of patients with LGMD who have abnormal expression of laminin 2 subunits. METHODS: We studied muscle biopsy specimens from 18 patients with LGMD using immunofluorescence with antibodies against dystrophin C-terminus, beta-dystroglycan, alpha-sarcoglycan, gamma-sarcoglycan, and the laminin subunits merosin, beta 1, and gamma 1. Of the 18 biopsy specimens, 9 were available for electron microscopic examination of the muscle basement membrane. The clinical features associated with abnormal laminin beta 1 chain immunoreactivity were further described. RESULTS: Laminin beta 1 chain was either barely detectable or severely reduced in 3 cases of patients with LGMD in which the biopsy specimens showed normal staining with the other antibodies. Patients in all 3 cases had common clinical features consistent with a slowly progressive, adult-onset LGMD. Specimens from 2 of the 3 cases that were available for ultrastructural examination showed significant abnormalities of the muscle fiber basement membrane. CONCLUSIONS: Abnormal expression of laminin beta 1 chain without concomitant deficiency of alpha-sarcoglycan in skeletal muscle has not been previously described in LGMD. Reduced laminin beta 1 chain immunoreactivity may potentially serve as a marker for defining subsets of individuals with LGMD, in particular those with slowly progressive, adult-onset pelvifemoral presentation. The abnormality of muscle fiber basement membranes in specimens from cases that were available for ultrastructural study suggests that defects in the extracellular matrix may play a role in the pathogenesis of this subset of LGMD.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Analysis of human muscle stem cells reveals a differentiation-resistant progenitor cell population expressing Pax7 capable of self-renewal. 19097049

    Studies using mouse models have established a critical role for resident satellite stem cells in skeletal muscle development and regeneration, but little is known about this paradigm in human muscle. Here, using human muscle stem cells, we address their lineage progression, differentiation, migration, and self-renewal. Isolated human satellite cells expressed alpha7-integrin and other definitive muscle markers, were highly motile on laminin substrates and could undergo efficient myotube differentiation and myofibrillogenesis. However, only a subpopulation of the myoblasts expressed Pax7 and displayed a variable lineage progression as measured by desmin and MyoD expression. Analysis identified a differentiation-resistant progenitor cell population that was Pax7+/desmin- and capable of self-renewal. This study extends our understanding of the role of Pax7 in regulating human satellite stem cell differentiation and self-renewal.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1922Z
    Nombre del producto:
    Anti-Laminin α2 Antibody, clone 5H2, Azide Free

  • Differences in adhesion and collagen gel contraction between fibroblasts from various types of odontogenic cyst. 8060261

    Fibroblasts were grown from explants of normal gingiva and foreskin, and from walls of dentigerous, radicular and residual cysts, as well as keratocysts of basal-cell naevus syndrome and non-syndrome origin. Dentigerous-cyst fibroblast adhesion to poly-L-lysine-coated glass was unaffected by all adhesion-related glycoproteins. Chondroitin sulphate, fibronectin and heparan sulphate enhanced attachment of all other fibroblasts. Chondroitin-sulphate and fibronectin-enhanced adhesion was blocked by an arg-gly-asp peptide. Fibronectin, chondroitin sulphate and laminin all promoted collagen lattice contraction using normal gingival fibroblasts and low-serum media. Fibronectin had a greater effect than chondroitin sulphate and laminin. In media with standard serum, all cyst fibroblast lines examined demonstrated similar gel contraction curves with the exception of dentigerous cyst-derived fibroblasts, which contracted at decreased rates. Suppression of gel contraction was seen with dentigerous-cyst fibroblasts with all extracellular matrix glycoproteins and low serum. Dentigerous-cyst fibroblast attachment to glass and behaviour in gel lattices suggest that these cells express different functional attachment factors from other cyst fibroblast types.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB2030
    Nombre del producto:
    Anti-Chondroitin 4 Sulfate Antibody, clone BE-123

  • Novel mutations in collagen VI genes: expansion of the Bethlem myopathy phenotype. 11865138

    OBJECTIVE: To investigate the molecular basis of autosomal dominant limb-girdle muscular dystrophy (AD-LGMD) in three large new families. METHODS AND RESULTS: Genome-wide linkage was performed to show that the causative gene in all three families localized to chromosome 21q22.3 (Zmax = 10.3; theta = 0). This region contained the collagen VI alpha1 and alpha2 genes, which have been previously shown to harbor mutations causing a relatively mild congenital myopathy with contractures (Bethlem myopathy). Screening of the collagen VI alpha1 and alpha2 genes revealed novel, causative mutations in each family (COL6A1-K121R, G341D; COL6A2-D620N); two of these mutations were in novel regions of the proteins not previously associated with disease. Collagen VI is a ubiquitously expressed component of connective tissue; however, both limb-girdle muscular dystrophy and Bethlem myopathy patients show symptoms restricted to skeletal muscle. To address the muscle-specific symptoms resulting from collagen VI mutations, the authors studied three patient muscle biopsies at the molecular level (protein expression). A marked reduction of laminin beta1 protein in the myofiber basal lamina in all biopsies was found, although this protein was expressed normally in the neighboring capillary basal laminae. CONCLUSIONS: The authors' studies widen the clinical spectrum of Bethlem myopathy and suggest collagen VI etiology should be investigated in dominant limb-girdle muscular dystrophy. The authors hypothesize that collagen VI mutations lead to muscle-specific defects of the basal lamina, and may explain the muscle-specific symptoms of Bethlem and limb-girdle muscular dystrophy patients with collagen VI mutations.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • The release of substance P from cultured dorsal root ganglion neurons requires the non-neuronal cells around these neurons. 17986814

    Substance P is known to be released from dorsal root ganglion (DRG) neurons, but the possible involvement of non-neuronal cells in the process of substance P release is not known. During the culture period, the number of surviving DRG neurons, the total substance P content from the culture medium and DRG cells, and the total protein of DRG cells were monitored. Both the number of surviving neurons and the total substance P content decreased in a time-dependent manner, whereas the total protein synthesis was increased. The localization of substance P in small-to-medium-sized neurons was further confirmed by immunocytochemistry. Finally, the substance P release levels from the neuronal and non-neuronal enrichments were investigated by radioimmunoassay. Both partially purified DRG neurons and non-neuronal cells exhibited a weaker substance P release response to capsaicin or KCl, relative to unpurified DRG cells. The total substance P content from the partially purified DRG neurons was almost the same as that from the unpurified DRG cells, but much more than that from the partially purified DRG non-neuronal cells. These findings suggest that substance P is released from DRG neurons, and this process should require the coexistence of neurons and non-neuronal cells.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB3418
    Nombre del producto:
    Anti-MAP2 Antibody, clone AP20

  • Prenatal diagnosis in laminin alpha2 chain (merosin)-deficient congenital muscular dystrophy: a collective experience of five international centers. 16084089

    The congenital muscular dystrophies (CMD) are clinically and genetically heterogeneous. The merosin (laminin alpha2 chain) deficient form (MDC1A), is characterized clinically by neonatal hypotonia, delayed motor milestones and associated contractures. It is caused by deficiency in the basal lamina of muscle fibers of the alpha2 chain of laminins 2 and 4 (LAMA2 gene at 6q22-23). Laminin alpha2 chain is also expressed in fetal trophoblast, which provides a suitable tissue for prenatal diagnosis in families where the index case has total deficiency of the protein. This article reports the collective experience of five centers over the past 10 years in 114 prenatal diagnostic studies using either protein analysis of the chorionic villus (CV) of the trophoblast plus DNA molecular studies with markers flanking the 6q22-23 region and intragenic polymorphisms (n=58), or using only DNA (n=44) or only protein (n=12) approaches. Of the 102 fetuses studied by molecular genetics, 27 (26%) were predicted to be affected while 75 (74%) were considered as unaffected, with 52 (51%) being heterozygous, thus conforming closely to an autosomal recessive inheritance. In 18 of the 27 affected fetuses, the trophoblast was studied by immunocytochemistry and there was a total or only traces deficiency of the protein in CV basement membrane in all. In 10 cases material from the presumably affected fetus was available for analysis after termination of the pregnancy and immunohistochemical study confirmed the diagnosis in all of them. Prenatal studies of 'at risk' pregnancies in the five centers produced neither false negative (merosin-deficiency in CVs in a normal fetus), nor false positive (normal merosin expression in CVs and affected child), indicating the reliability of the technique, when all the necessary controls are done. Our experience suggests that protein and DNA analysis can be used either independently or combined, according to the facilities of each center, to provide accurate prenatal diagnosis of the MDC1A, and have an essential role in genetic counseling.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1922
    Nombre del producto:
    Anti-Laminin α2 Antibody, clone 5H2

  • Inhibition of integrin-mediated crosstalk with epidermal growth factor receptor/Erk or Src signaling pathways in autophagic prostate epithelial cells induces caspase-inde ... 17475774

    In vivo in the prostate gland, basal epithelial cells adhere to laminin 5 (LM5) via alpha3beta1 and alpha6beta4 integrins. When placed in culture primary prostate basal epithelial cells secrete and adhere to their own LM5-rich matrix. Adhesion to LM5 is required for cell survival that is dependent on integrin-mediated, ligand-independent activation of the epidermal growth factor receptor (EGFR) and the cytoplasmic tyrosine kinase Src, but not PI-3K. Integrin-mediated adhesion via alpha3beta1, but not alpha6beta4 integrin, supports cell survival through EGFR by signaling downstream to Erk. PC3 cells, which do not activate EGFR or Erk on LM5-rich matrices, are not dependent on this pathway for survival. PC3 cells are dependent on PI-3K for survival and undergo caspase-dependent death when PI-3K is inhibited. The death induced by inhibition of EGFR or Src in normal primary prostate cells is not mediated through or dependent on caspase activation, but depends on the induction of reactive oxygen species. In addition the presence of an autophagic pathway, maintained by adhesion to matrix through alpha3beta1 and alpha6beta4, prevents the induction of caspases when EGFR or Src is inhibited. Suppression of autophagy is sufficient to induce caspase activation and apoptosis in LM5-adherent primary prostate epithelial cells.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1952P

  • Localization of three distinct heparin-binding domains of laminin by monoclonal antibodies. 3350814

    Monoclonal antibodies were utilized to localize novel heparin-binding domains of laminin. A solid-phase radioligand binding assay was designed such that [3H] heparin bound to laminin in a time- and concentration-dependent manner. Tritiated heparin binding to laminin was saturable and specific as determined by competition with unlabeled heparin, dextran sulfate, and dermatan sulfate. By Scatchard analysis, two distinct dissociation constants were calculated (Kd = 50 and 130 nM), suggesting the presence of at least two binding sites for heparin on laminin. Tritiated heparin bound to thrombin-resistant (600 kDa) and chymotrypsin-resistant (440 kDa) laminin fragments, both known to lack the terminal globular domain of the long arm. Sodium dodecyl sulfate-polyacrylamide gels of chymotrypsin- and thermolysin-digested laminin chromatographed on a heparin-Sepharose column showed multiple proteolytic fragments binding to the column. Monoclonal antibodies generated against laminin were tested for their ability to inhibit [3H]heparin binding to laminin. Four monoclonal antibodies significantly inhibited the binding of [3H]heparin to laminin in the range of 15-21% inhibition. Laminin-monoclonal antibody interactions examined by electron microscopy showed that one antibody reacted at the terminal globular domain of the long arm, domain Hep-1, while epitopes for two of these monoclonal antibodies were located on the lateral arms of laminin, domain Hep-2, and the fourth monoclonal antibody bound below the cross-region of laminin, domain Hep-3. When two monoclonal antibodies recognizing distinctly different regions of laminin were added concomitantly, the inhibition of [3H]heparin binding to laminin increased almost 2-fold. These results suggest that at least two novel heparin-binding domains of laminin may be located in domains distinct from the terminal globular domain of the long arm.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo