Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Recombinant dna technique included in method of making a...
Reexamination Certificate
2001-08-16
2004-01-13
Prouty, Rebecca E. (Department: 1652)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Recombinant dna technique included in method of making a...
C435S183000, C435S201000, C435S202000, C435S203000, C435S204000, C435S205000, C435S206000, C435S207000, C435S208000, C435S209000, C435S210000, C435S211000, C435S325000, C435S349000, C435S252300, C435S320100, C530S350000
Reexamination Certificate
active
06677137
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to an avian and reptile derived polynucleotide encoding a polypeptide having heparanase catalytic activity. The present invention further relates to the use of the signal peptide of avian and/or reptile heparanase for expression of membrane associated and/or secreted proteins in heterologous expression systems.
Glycosaminoglycans (GAGs)
GAGs are polymers of repeated disaccharide units consisting of uronic acid and a hexosamine. Biosynthesis of GAGs except hyaluronic acid is initiated from a core protein. Proteoglycans may contain several GAG side chains from similar or different families. GAGs are synthesized as homopolymers which may subsequently be modified by N-deacetylation and N-sulfation, followed by C5-epimerization of glucuronic acid to iduronic acid and O-sulfation. The chemical composition of GAGs from various tissues varies highly.
The natural metabolism of GAGs in animals is carried out by hydrolysis. Generally, the GAGs are degraded in a two step procedure. First the proteoglycans are internalized in endosomes, where initial depolymerization of the GAG chain takes place. This step is mainly hydrolytic and yields oligosaccharides. Further degradation is carried out following fusion with lysosome, where desulfation and exolytic depolymerization to monosaccharides take place (42).
The only GAG degrading endolytic enzymes characterized so far in animals are the hyaluronidases. The hyaluronidases are a family of 1-4 endoglucosaminidases that depolymerize hyaluronic acid and chondroitin sulfate. The cDNAs encoding sperm associated PH-20 (Hyal3), and the lysosomal hyaluronidases Hyal 1 and Hyal 2 were cloned and published (27). These enzymes share an overall homology of 40% and have different tissue specificities, cellular localizations and pH optima for activity.
Exolytic hydrolases are better characterized, among which are &bgr;-glucoronidase, &agr;-L-iduronidase, and &bgr;-N-acetylglucosaminidase. In addition to hydrolysis of the glycosidic bond of the polysaccharide chain, GAG degradation involves desulfation, which is catalyzed by several lysosomal sulfatases such as N-acetylgalactosamine-4-sulfatase, iduronate-2-sulfatase and heparin sulfamidase. Deficiency in any of lysosomal GAG degrading enzymes results in a lysosomal storage disease, mucopolysaccharidosis.
Glycosyl Hydrolases
Glycosyl hydrolases are a widespread group of enzymes that hydrolyze the o-glycosidic bond between two or more carbohydrates or between a carbohydrate and a noncarbohydrate moiety. The enzymatic hydrolysis of glycosidic bond occurs by using major one or two mechanisms leading to overall retention or inversion of the anomeric configuration. In both mechanisms, catalysis involves two residues: a proton donor and a nucleophile. Glycosyl hydrolyses have been classified into 58 families based on amino acid similarities. The glycosyl hydrolyses from families 1, 2, 5, 10, 17, 30, 35, 39 and 42 act on a large variety of substrates, however, they all hydrolyze the glycosidic bond in a general acid catalysis mechanism, with retention of the anomeric configuration. The mechanism involves two glutamic acid residues, which are the proton donor and the nucleophile, with an aspargine which always precedes the proton donor. Analyses of a set of known 3D structures from this group of enzymes revealed that their catalytic domains, despite the low level of sequence identity, adopt a similar (&agr;/&bgr;) 8 fold with the proton donor and the nucleophile located at the C-terminal ends of strands &bgr;4 and &bgr;7, respectively. Mutations in the functional conserved amino acids of lysosomal glycosyl hydrolases were identified in lysosomal storage diseases.
Lysosomal glycosyl hydrolases including &bgr;-glucuronidase, &bgr;-manosidase, &bgr;-glucocerebrosidase, &bgr;-galactosidase and &agr;-L-iduronidase, are all exo-glycosyl hydrolases, belong to the GH-A clan and share a similar catalytic site. However, many endo-glucanases from various organisms, such as bacterial and fungal xylenases and cellulases share this catalytic domain (1).
Heparan Sulfate Proteoglycans (HSPGs)
HSPGs are ubiquitous macromolecules associated with the cell surface and extracellular matrix (ECM) of a wide range of cells of vertebrate and invertebrate tissues (3-7). The basic HSPG structure consists of a protein core to which several linear heparan sulfate chains are covalently attached. The polysaccharide chains are typically composed of repeating hexuronic and D-glucosamine disaccharide units that are substituted to a varying extent with N- and O-linked sulfate moieties and N-linked acetyl groups (3-7). Studies on the involvement of ECM molecules in cell attachment, growth and differentiation revealed a central role of HSPGs in embryonic morphogenesis, angiogenesis, metastasis, neurite outgrowth and tissue repair (3-7). The heparan sulfate (HS) chains, which are unique in their ability to bind a multitude of proteins, ensure that a wide variety of effector molecules cling to the cell surface (6-8). HSPGs are also prominent components of blood vessels (5). In large vessels they are concentrated mostly in the intima and inner media, whereas in capillaries they are found mainly in the subendothelial basement membrane where they support proliferating and migrating endothelial cells and stabilize the structure of the capillary wall. The ability of HSPGs to interact with ECM macromolecules such as collagen, laminin and fibronectin, and with different attachment sites on plasma membranes suggests a key role for this proteoglycan in the self-assembly and insolubility of ECM components, as well as in cell adhesion and locomotion. Cleavage of HS may therefore result in disassembly of the subendothelial ECM and hence may play a decisive role in extravasation of normal and malignant blood-borne cells (9-11). HS catabolism is observed in inflammation, wound repair, diabetes, and cancer metastasis, suggesting that enzymes, which degrade HS, play important roles in pathologic processes.
Heparanase
Heparanase is a glycosylated enzyme that is involved in the catabolism of certain glycosaminoglycans. It is an endoglucuronidase that cleaves heparan sulfate at specific intrachain sites (12-15). Interaction of T and B lymphocytes, platelets, granulocytes, macrophages and mast cells with the subendothelial extracellular matrix (ECM) is associated with degradation of heparan sulfate by heparanase activity (16). Placenta heparanase acts as an adhesion molecule or as a degradative enzyme depending on the pH of the microenvironment (17).
Heparanase is released from intracellular compartments (e.g., lysosomes, specific granules) in response to various activation signals (e.g., thrombin, calcium ionophores, immune complexes, antigens and mitogens), suggesting its regulated involvement in inflammation and cellular immunity responses (16).
It was also demonstrated that heparanase can be readily released from human neutrophils by 60 minutes incubation at 4° C. in the absence of added stimuli (18).
Gelatinase, another ECM degrading enzyme, which is found in tertiary granule s of human neutrophils with heparanase, is secreted from the neutrophils in response to phorbol 12-myristate 13-acetate (PMA) treatment (19-20).
In contrast, various tumor cells appear to express and secrete heparanase in a constitutive manner in correlation with their metastatic potential (21).
Degradation of heparan sulfate by heparanase results in the release of heparin-binding growth factors, enzymes and plasma proteins that are sequestered by heparan sulfate in basement membranes, extracellular matrices and cell surfaces (22-23).
Heparanase activity has been described in a number of cell types including cultured skin fibroblasts, human neutrophils, activated rat T-lymphocytes, normal and neoplastic murine B-lymphocytes, human monocytes and human umbilical vein endothelial cells, SK hepatoma cells, human placenta and human platelets.
A procedure for purification of natural heparanase was reported for SK hepatoma cells and human
Goldshmidt Orit
Michal Israel
Pecker Iris
Vlodavsky Israel
Zcharia Eyal
G. E. Ehrlich (1995) Ltd.
Insight Strategy & Marketing Ltd.
Prouty Rebecca E.
Rho Manjunath N.
LandOfFree
Avian and reptile derived polynucleotide encoding a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Avian and reptile derived polynucleotide encoding a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Avian and reptile derived polynucleotide encoding a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3232520