The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
F. Ramirez - One of the best experts on this subject based on the ideXlab platform.
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Complete primary structure of a sea urchin type IV Collagen alpha chain and analysis of the 5' end of its gene.
The Journal of biological chemistry, 1993Co-Authors: Jy Exposito, M. D'alessio, M Di Liberto, F. RamirezAbstract:Abstract We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
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Complete primary structure of a sea urchin type IV Collagen alpha chain and analysis of the 5' end of its gene.
Journal of Biological Chemistry, 1993Co-Authors: Jy Exposito, M. D'alessio, M. Diliberto, F. RamirezAbstract:We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
Jy Exposito - One of the best experts on this subject based on the ideXlab platform.
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Complete primary structure of a sea urchin type IV Collagen alpha chain and analysis of the 5' end of its gene.
The Journal of biological chemistry, 1993Co-Authors: Jy Exposito, M. D'alessio, M Di Liberto, F. RamirezAbstract:Abstract We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
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Complete primary structure of a sea urchin type IV Collagen alpha chain and analysis of the 5' end of its gene.
Journal of Biological Chemistry, 1993Co-Authors: Jy Exposito, M. D'alessio, M. Diliberto, F. RamirezAbstract:We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
Detlef Schuppan - One of the best experts on this subject based on the ideXlab platform.
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Collagen type xviii endostatin is differentially expressed in primary and metastatic colorectal cancers and ovarian carcinomas
British Journal of Cancer, 2001Co-Authors: U Guenther, Hermann Herbst, Michael Bauer, C Isbert, H J Buhr, E O Riecken, Detlef SchuppanAbstract:Collagen type XVIII (C18) is a Nonfibrillar Collagen of basement membranes. Its C-terminal fragment, endostatin, has been identified as an inhibitor of angiogenesis. C18 is predominantly expressed by hepatocytes of normal, cirrhotic and neoplastic liver. We compared the patterns of C18 RNA-expression in colonic adenocarcinoma metastases, which represent the most frequently occurring liver tumours, to normal colon mucosa, to primary colon cancers and to ovarian cancers which are often morphologically similar to colonic cancer or metastasis. Two C18-specific RNA-probes were generated to perform in situ hybridization combined with immunohistochemistry for cytokeratin, vimentin and the endothelial marker CD31, in order to characterize the C18-expressing cells. C18/endostatin protein was localized by immunohistology. In colorectal carcinomas and their liver metastases high levels of C18 transcripts were observed in endothelial cells and fibroblasts/myofibroblasts, whereas C18 RNA was virtually absent from carcinoma cells. Ovarian carcinomas displayed high C18 RNA expression both in carcinoma and stromal cells, indicating that induction of C18 transcription in tumour stromal cells is independent of the ability of carcinoma cells to express C18. While the role of tumour cell derived C18 in cancer growth regulation remains unknown, stimulation of proteolysis of the locally strongly expressed C18 to endostatin could offer an attractive approach for a targeted antineoplastic therapy.
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Collagen type XVIII/endostatin is differentially expressed in primary and metastatic colorectal cancers and ovarian carcinomas
British Journal of Cancer, 2001Co-Authors: U Guenther, Hermann Herbst, Michael Bauer, C Isbert, H J Buhr, E O Riecken, Detlef SchuppanAbstract:Collagen type XVIII (C18) is a Nonfibrillar Collagen of basement membranes. Its C-terminal fragment, endostatin, has been identified as an inhibitor of angiogenesis. C18 is predominantly expressed by hepatocytes of normal, cirrhotic and neoplastic liver. We compared the patterns of C18 RNA-expression in colonic adenocarcinoma metastases, which represent the most frequently occurring liver tumours, to normal colon mucosa, to primary colon cancers and to ovarian cancers which are often morphologically similar to colonic cancer or metastasis. Two C18-specific RNA-probes were generated to perform in situ hybridization combined with immunohistochemistry for cytokeratin, vimentin and the endothelial marker CD31, in order to characterize the C18-expressing cells. C18/endostatin protein was localized by immunohistology. In colorectal carcinomas and their liver metastases high levels of C18 transcripts were observed in endothelial cells and fibroblasts/myofibroblasts, whereas C18 RNA was virtually absent from carcinoma cells. Ovarian carcinomas displayed high C18 RNA expression both in carcinoma and stromal cells, indicating that induction of C18 transcription in tumour stromal cells is independent of the ability of carcinoma cells to express C18. While the role of tumour cell derived C18 in cancer growth regulation remains unknown, stimulation of proteolysis of the locally strongly expressed C18 to endostatin could offer an attractive approach for a targeted antineoplastic therapy. © 2001 Cancer Research Campaign http://www.bjcancer.com
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Collagen type XVIII/endostatin is differentially expressed in primary and metastatic colorectal cancers and ovarian carcinomas.
British journal of cancer, 2001Co-Authors: Guenther U, Hermann Herbst, Michael Bauer, C Isbert, H J Buhr, E O Riecken, Detlef SchuppanAbstract:Collagen type XVIII (C18) is a Nonfibrillar Collagen of basement membranes. Its C-terminal fragment, endostatin, has been identified as an inhibitor of angiogenesis. C18 is predominantly expressed by hepatocytes of normal, cirrhotic and neoplastic liver. We compared the patterns of C18 RNA-expression in colonic adenocarcinoma metastases, which represent the most frequently occurring liver tumours, to normal colon mucosa, to primary colon cancers and to ovarian cancers which are often morphologically similar to colonic cancer or metastasis. Two C18-specific RNA-probes were generated to perform in situ hybridization combined with immunohistochemistry for cytokeratin, vimentin and the endothelial marker CD31, in order to characterize the C18-expressing cells. C18/endostatin protein was localized by immunohistology. In colorectal carcinomas and their liver metastases high levels of C18 transcripts were observed in endothelial cells and fibroblasts/myofibroblasts, whereas C18 RNA was virtually absent from carcinoma cells. Ovarian carcinomas displayed high C18 RNA expression both in carcinoma and stromal cells, indicating that induction of C18 transcription in tumour stromal cells is independent of the ability of carcinoma cells to express C18. While the role of tumour cell derived C18 in cancer growth regulation remains unknown, stimulation of proteolysis of the locally strongly expressed C18 to endostatin could offer an attractive approach for a targeted antineoplastic therapy.
M. D'alessio - One of the best experts on this subject based on the ideXlab platform.
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Complete primary structure of a sea urchin type IV Collagen alpha chain and analysis of the 5' end of its gene.
The Journal of biological chemistry, 1993Co-Authors: Jy Exposito, M. D'alessio, M Di Liberto, F. RamirezAbstract:Abstract We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
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Complete primary structure of a sea urchin type IV Collagen alpha chain and analysis of the 5' end of its gene.
Journal of Biological Chemistry, 1993Co-Authors: Jy Exposito, M. D'alessio, M. Diliberto, F. RamirezAbstract:We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a Nonfibrillar Collagen chain structurally homologous to the vertebrate type IV Collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-Collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-Collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-Collagenous domains with those of the vertebrate type IV Collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
David E. Birk - One of the best experts on this subject based on the ideXlab platform.
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secretion and organization of a cornea like tissue in vitro by stem cells from human corneal stroma
Investigative Ophthalmology & Visual Science, 2007Co-Authors: Nirmala Sundarraj, Martha L. Funderburgh, David E. Birk, Stephen A K Harvey, James L. FunderburghAbstract:The cornea is the outermost surface of the eye and the portal for light entry into the visual system. The strength and transparency of this organ rely on the highly organized extracellular matrix (ECM) of the corneal stroma, a tissue elaborated by unique neural crest-derived cells known as keratocytes. The stromal tissue is composed of 20 to 70 acellular Collagenous lamellae of heterotypic types I and V fibrils with small uniform diameters, tightly packed in parallel orientation.1 This fibrillar Collagen is embedded in a matrix of glycoproteins and proteoglycans that includes type VI Nonfibrillar Collagen and a unique family of keratan sulfate-containing proteoglycans essential for corneal transparency. The keratocytes, sandwiched between stromal lamellae, are the source of the molecular components of the stromal ECM and are largely quiescent in adult mammals. During wound healing, keratocytes become mitotic and motile, undergoing alteration of their ECM phenotype, depositing opaque scar tissue capable of causing permanent disruption of visual acuity. Keratoplasty using donated human tissue is currently the only effective procedure to correct visual impairment resulting from stromal scarring. We recently identified a small population of cells in human corneal stroma with properties of adult stem cells.2 As do other adult stem cells, these cells express mRNA and protein for the multidrug transporter ABCG2 and can be expanded in culture through a number of population doublings without loss of this expression. These cells also express PAX6, a gene product present in embryonic and developing stromal cells but not in adult keratocytes.2 Like mesenchymal stem cells, corneal stromal stem cells (hCSSC) exhibit clonal growth and a potential for differentiation into multiple distinct tissue types.2 They express gene products characteristic of chondrocytes and neural cells when placed in culture environments known to elicit these phenotypes from other adult stem cell populations.2 As they differentiate, hCSSC lose ABCG2 and PAX6 expression. These stem cell markers were not regained when the differentiated cells were returned to stem cell maintenance culture conditions.2 The hCSSC expressed keratocan mRNA and protein as well as high molecular weight keratan sulfate when cultured in serum-free medium containing FGF2 and insulin. Keratocan glycanated with keratan sulfate is a unique product of the corneal stroma and is lost during in vitro expansion of cultured keratocytes.3,4 Secretion of this proteoglycan by cells derived from passaged hCSSC represents the first demonstration of induction of this keratocyte-specific molecule by passaged human cells in culture. Expression of these unique keratocyte products suggests hCSSC can adopt a keratocyte phenotype; however, in monolayer culture, these cells do not accumulate and organize the highly specialized ECM produced by stromal keratocytes in vivo. In the present study we examined the ability of three-dimensional culture conditions to induce elaboration of an organized stromal matrix by hCSSC. We also used gene array analyses to provide a more complete assessment of the gene expression phenotype of human keratocytes. These analyses yielded a panel of 18 genes providing an improved molecular definition of keratocyte phenotype. We found that culture of the hCSSC as a cell pellet in serum-free medium in the absence of rigid scaffolding or substratum induced an expression pattern of genes similar to that of keratocytes. Matrix expression and Collagen organization in these pellets exhibited aspects of those seen in corneal stroma.
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Corneal cell-matrix interactions: type VI Collagen promotes adhesion and spreading of corneal fibroblasts.
Experimental cell research, 1992Co-Authors: Kathleen J. Doane, George Yang, David E. BirkAbstract:Type VI Collagen is a Nonfibrillar Collagen present as a network throughout the chick secondary stroma. Immunolocalization of type VI Collagen both in the chick corneal stroma and in other systems demonstrates that type VI Collagen is present associated with cells and between striated fibrils. We hypothesize that type VI Collagen may function in cell-matrix interactions important in corneal development. To examine this possibility, we have isolated and characterized bovine corneal type VI Collagen and determined that the chain composition and morphology of type VI Collagen isolated from cornea is similar to that isolated from other sources. The tissue form of type VI Collagen was localized to filaments forming a network around fibrils and close to corneal fibroblasts. We then analyzed relative attachment and spreading on type VI Collagen as compared to the other Collagens present in the secondary stroma, and found that although corneal fibroblasts attach equally well to type VI and type I Collagen, cells spread to a much greater extent on type VI Collagen. Although corneal fibroblasts do have an RGD-dependent receptor which functions during adhesion to fibronectin, attachment to type VI Collagen is RGD-independent unless the molecule is denatured. Blocking of the RGD-dependent receptor with soluble RGD peptides results in no change in attachment or spreading. These data imply a role for type VI Collagen in cell-matrix interactions during corneal stroma development.