Biomaterial Database

Antibody specificities of Thai and Australian scleroderma sera with topoisomerase I recombinant fusion proteins. 1993

D S Cram, and N Fisicaro, and L J McNeilage, and R L Coppel, and L C Harrison

Burnet Clinical Research Unit, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.

Autoantibodies that react with the nuclear enzyme topoisomerase I (Topo I) are used as a diagnostic marker of diffuse scleroderma. To better define immune reactivity to Topo I, antibody epitopes in two patient populations were analyzed using recombinant Topo I proteins. Two overlapping partial cDNA clones encoding the complete amino acid sequence of Topo I were isolated from human placenta. Using the polymerase chain reaction, specific regions of Topo I were amplified and cloned into the pGEX expression vectors. To map Topo I epitopes, recombinant fusion proteins were analyzed by immunoblotting with 66 anti-Topo I sera from Thai and Australian patients with diffuse scleroderma. Six distinct epitope regions were identified along the length of the 765 amino acid enzyme. Almost all sera contained antibodies that recognized the midregion of Topo I (amino acids 453-560), as well as antibodies to one of more of the other epitope regions. Sixty percent of the sera contained antibodies that recognized a COOH-terminal epitope region (amino acids 658-765) encompassing the active site of the enzyme. This subset of Topo I antibodies could be responsible for the inhibition of enzymatic activity previously reported in vitro. Heterogeneous patterns of reactivity with the six Topo I epitope regions were observed, although over half the sera could be assigned to one of six distinct patterns. In general, antibodies in the Thai sera reacted more strongly with the six epitope regions. Furthermore, two of the epitope regions reacted exclusively with Thai sera, suggesting a degree of racial or geographical specificity in the autoantibody response to Topo I. The identification of multiple epitopes in Topo I conforms with the polyclonal autoantibody response to intracellular Ag found in other multisystem autoimmune diseases and is presumed to be driven by the presentation of multiple peptides from Topo I itself.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010449	Peptide Mapping	Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.	Fingerprints, Peptide,Peptide Fingerprinting,Protein Fingerprinting,Fingerprints, Protein,Fingerprint, Peptide,Fingerprint, Protein,Fingerprinting, Peptide,Fingerprinting, Protein,Mapping, Peptide,Peptide Fingerprint,Peptide Fingerprints,Protein Fingerprint,Protein Fingerprints
D011993	Recombinant Fusion Proteins	Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.	Fusion Proteins, Recombinant,Recombinant Chimeric Protein,Recombinant Fusion Protein,Recombinant Hybrid Protein,Chimeric Proteins, Recombinant,Hybrid Proteins, Recombinant,Recombinant Chimeric Proteins,Recombinant Hybrid Proteins,Chimeric Protein, Recombinant,Fusion Protein, Recombinant,Hybrid Protein, Recombinant,Protein, Recombinant Chimeric,Protein, Recombinant Fusion,Protein, Recombinant Hybrid,Proteins, Recombinant Chimeric,Proteins, Recombinant Fusion,Proteins, Recombinant Hybrid
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004264	DNA Topoisomerases, Type I	DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. DNA Topoisomerases, Type I enzymes reduce the topological stress in the DNA structure by relaxing the superhelical turns and knotted rings in the DNA helix.	DNA Nicking-Closing Protein,DNA Relaxing Enzyme,DNA Relaxing Protein,DNA Topoisomerase,DNA Topoisomerase I,DNA Topoisomerase III,DNA Topoisomerase III alpha,DNA Topoisomerase III beta,DNA Untwisting Enzyme,DNA Untwisting Protein,TOP3 Topoisomerase,TOP3alpha,TOPO IIIalpha,Topo III,Topoisomerase III,Topoisomerase III beta,Topoisomerase IIIalpha,Topoisomerase IIIbeta,DNA Nicking-Closing Proteins,DNA Relaxing Enzymes,DNA Type 1 Topoisomerase,DNA Untwisting Enzymes,DNA Untwisting Proteins,Topoisomerase I,Type I DNA Topoisomerase,III beta, Topoisomerase,III, DNA Topoisomerase,III, Topo,III, Topoisomerase,IIIalpha, TOPO,IIIalpha, Topoisomerase,IIIbeta, Topoisomerase,Topoisomerase III, DNA,Topoisomerase, TOP3,beta, Topoisomerase III
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000918	Antibody Specificity	The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.	Antibody Specificities,Specificities, Antibody,Specificity, Antibody
D000939	Epitopes	Sites on an antigen that interact with specific antibodies.	Antigenic Determinant,Antigenic Determinants,Antigenic Specificity,Epitope,Determinant, Antigenic,Determinants, Antigenic,Specificity, Antigenic
D001315	Australia	The smallest continent and an independent country, comprising six states and two territories. Its capital is Canberra.	Canton and Enderbury Islands,Christmas Island,Christmas Island (Australia)