The labelling of proliferating cells by Ki67 and MIB-1 antibodies depends on the binding of a nuclear protein to the DNA.
The antigen Ki-67 Ag, regarded as a marker for proliferating cells, was identified as a protein(s) (pKi-67) which can exist free or associated with DNA as evidenced by DNA digestion of cells before or after immunolabeling with Ki-67. The dual nature of this antigen was also supported by reconstitution of Ki-67 Ag from purified DNA and nuclear proteins extracted from the K562 cell line. The immunoreactivity of the resulting complexes was examined in solution using Ki-67 and MIB-1 antibodies. The interaction between Ki-67 or MIB-1 antibodies and pKi-67 was enhanced in the presence of undegraded ds DNA, indicating that ds DNA modulates the conformation of pKi-67 and that the altered conformation of pKi-67 is more reactive than the pure protein to both Ki-67 and MIB-1 antibodies.
Lopez
F
F
Laboratoire d'Hématologie, Hôpital Cardiologique, Pessac, France.
Belloc
F
F
Lacombe
F
F
Dumain
P
P
Reiffers
J
J
Bernard
P
P
Boisseau
M R
MR
D000906:Antibodies / Q000378:metabolism*; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004273:DNA, Neoplasm / Q000378:metabolism*; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D019394:Ki-67 Antigen; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D014407:Tumor Cells, Cultured
D000906:Antibodies; D004273:DNA, Neoplasm; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D003513:Cycloheximide