Proliferation-associated nuclear antigen Ki-S1 is identical with topoisomerase II alpha. Delineation of a carboxy-terminal epitope with peptide antibodies.
Proliferation-linked expression of the nuclear Ki-S1 antigen is a significant prognostic indicator in mammary carcinomas. Here, we show staining of a protein of 170 kd by Ki-S1 antibody in immunoblots of Saccharomyces cerevisiae expressing human topoisomerase II alpha but not in the parental strain. In HL-60 cells containing both isoforms of human topoisomerase II, Ki-S1 antibody binds selectively to the 170-kd isoenzyme in a similar fashion as peptide-antibodies directed against amino acid residues 1 to 15 or 1512 to 1530 of human topoisomerase II alpha. Conversely, antibodies directed against carboxyl-terminal sequences of human topoisomerase II beta selectively stain a 180-kd protein. The immunoreactive pattern of V8 endoproteinase restriction digests of human topoisomerase II alpha was identical for Ki-S1-antibody and peptide-antibodies directed against residues 1512 to 1530 but different for peptide-antibodies directed against residues 1 to 15. The Rf values of the smallest fragment commonly recognized by Ki-S1 antibody and the carboxy terminus-specific peptide-antibody place the Ki-S1 epitope within the last 495 carboxyl-terminal amino acid residues of topoisomerase II alpha.
Boege
F
F
Medizinische Poliklinik, University of Würzburg, Germany.
Andersen
A
A
Jensen
S
S
Zeidler
R
R
Kreipe
H
H
D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology*; D015153:Blotting, Western; D004250:DNA Topoisomerases, Type II / Q000276:immunology*; D004268:DNA-Binding Proteins; D018604:Epitope Mapping / Q000379:methods; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007527:Isoenzymes / Q000276:immunology*; D009687:Nuclear Proteins / Q000276:immunology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology
D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D000939:Epitopes; D007074:Immunoglobulin G; D007527:Isoenzymes; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D004250:DNA Topoisomerases, Type II