Matrilin-3, Recombinant, Mouse

Matrilin-3 is a 50-60 kD extracellular matrix protein that belongs to the superfamily of von Willebrand factor A (VWA) containing proteins. It is primarily expressed in cartilage and functions as a bridging component between proteins of the collagenous matrix. 1-3 The mouse Matrilin-3 cDNA encodes a 481 amino acid (aa) precursor with a 27 aa signal sequence, an N-terminal VWA domain, four tandem EGF-like repeats, and a C-terminal coiled coil domain. 4 The Matrilins differ in the number of VWA domains (one or two) and EGF-like repeats (one, three, four, or ten) they contain. Mouse Matrilin-3 shares 82% aa sequence identity with human Matrilin-3. Within the first VWA domain, mouse Matrilin-3 shares approximately 51% aa sequence identity with mouse Matrilin-1, -2, and -4. The coiled coil domain of Matrilin-3 mediates disulfide-linked homo-oligomerization, with tetramer formation being the most dominant. 5-7 It can also assemble into hetero-oligomers with Matrilin-1. 5-7 Matrilin-3 is more plentiful than Matrilin-1 in the proliferative zone of the growth plate, whereas the reverse is true in the maturation zone. 5 Matrilin-3 interacts directly with Collagen IX and COMP. 8, 9 In the absence of Collagen IX, the expression of Matrilin-3 is unchanged, although it is retained inside chondrocytes and is not incorporated into the matrix. 9 Intracellular retention of Matrilin-3 also occurs with particular point mutations in the VWA domain that results in multiple epiphyseal dysplasia. 11-13 In contrast, a point mutation in the first EGF-like repeat which has been linked to hand osteoarthritis does not prevent Matrilin-3 secretion. 13 Matrilin-3 knockout mice do not display any obvious abnormalities, suggesting that other molecules may compensate for the lack of Matrilin-3. 10, Source: Human CD33 Signal Peptide (Met 1-Ala 16), Mouse Matrilin-3 (Ala 28-Arg 481), HHHHHH, A DNA sequence encoding the mature mouse Matrilin-3 (Ala 28-Arg 481, Accession # O35701) was fused to the signal peptide from human CD33 at the amino terminus and to a polyhistidine tag at the carboxy-terminus. The chimeric protein was expressed in a mouse myeloma cell line, NS0. Molecular Mass: Based on N-terminal sequencing, the recombinant mouse Matrilin-3 starts at Ala 35 and has a calculated molecular mass of approximately 49kD. The recombinant mouse Matrilin-3 preparation may also contain a small amount of protein whose N-terminius starts at Arg 39. As a result of glycosylation, the recombinant mouse Matrilin-3 migrates as an approximately 54-56 kD protein in SDS-PAGE under reducing conditions. Endotoxin Level: < 1.0 EU per 1 µg of the protein as determined by the LAL method. Activity: Measured by its ability to induce adhesion of ATDC-5 cells. rmMatrilin-3, immobilized at 10ug/ml (100 µL/well), induces 50-70% adhesion of ATDC-5 cells. , Reconstitution: It is recommended that sterile PBS be added to the vial to prepare a working stock solution of no less than 100ug/ml. The carrier-free protein should be used immediately upon reconstitution to avoid losses in activity due to non-specific binding to the inside surface of the vial. For long term storage as a dilute solution, a carrier protein (e.g. 0.1% HSA or BSA) should be added to the vial., , Storage: Lyophilized samples are stable for up to twelve months from date of receipt at -20°C. Upon reconstitution, this protein can be stored under sterile conditions at 2°-8° C for one month or at -20°C in a manual defrost freezer for three months without detectable loss of activity. Avoid repeated freeze-thaw cycles.