The murine Ki-67 cell proliferation antigen accumulates in the nucleolar and heterochromatic regions of interphase cells and at the periphery of the mitotic chromosomes in a process essential for cell cycle progression

摘要: We have isolated the murine homologue of human Ki-67 antigen. The antigen is used as a marker to assess proliferative capacity tumour cells; however, its cellular function not known. cDNA sequence (TSG126) was found contain 13 tandem repeats, making up more than half total protein size. A comparison this repetitive block counterpart, which contains 16 consecutive repeat units, revealed several conserved motifs, including one motif frequently observed in proteins interacting with DNA. An antiserum developed against product TSG126 clone identified an apparent molecular mass 360 kDa, mainly expressed proliferating cells. begins accumulate during late G1 stage cell cycle and first seen numerous small granules evenly distributed throughout nucleus. During S G2 phases, larger foci that overlap nucleoli heterochromatic regions are formed. At onset mitosis undergoes dramatic redistribution process becomes associated surface condensed chromosomes. relative absence from interphase cells strongly argues model where association mitotic chromosomes merely reflects mechanism for symmetrical distribution nucleolar between daughter Instead, intracellular suggests it could chromatin-associated both Microinjection anti-TSG126 antibodies into Swiss-3T3 fibroblasts delay progression, indicating has essential nuclear function.