Ki-67 Monoclonal Antibody (20Raj1), eBioscience™, Invitrogen™

Description

The MAb 20Raj1 recognizes the human Ki-67 protein. Two isoforms of Ki-67 exist, a 345 and 395 kDa form that are expressed in dividing cells. Ki-67 is expressed in all cell types and is detectable during active phases of the cell cycle (G1, S, G2, and mitosis) but is absent from resting cells (G0). During interphase, Ki-67 expression is localized to the nucleus but redistributes to the chromosomes during mitosis and has specifically been found to associate with heterochromatin-bound proteins such as chromobox protein homolog 3 (CBX3). In studies of tumor cells, Ki-67 expression has been used as a marker for determining the fraction of proliferating cells within a given population of tumor cells. This MAb 20Raj1 recognizes canine (dog) Ki-67.

Ki-67 is a nuclear protein that is expressed during various stages in the cell cycle, particularly during late G1, S, G2, and M phases. The protein has a forkhead associated domain (FHA) through which it associates with euchromatin at the perichromosomal layer, the centromeric heterochromatin, and the nucleolus. Ki-67 is shown to have a cell cycle dependent topographical distribution with perinucleolar expression at G1, expression in the nuclear matrix at G2, and expression on the chromosomes during M phase. Ki-67 is commonly used as a proliferation marker because it is not detected in G0 cells, but increases steadily from G1 through mitosis. Ki-67 antibodies are useful in establishing the cell growing fraction in neoplasms. In neoplastic tissues, the prognostic value is comparable to the tritiated thymidine-labelling index. The correlation between low Ki-67 index and histologically low-grade tumors is strong. Ki-67 is routinely used as a neuronal marker of cell cycling and proliferation.