Proliferating cell nuclear antigen in normal and regenerating rat livers.
Immunohistochemical analysis using proliferating cell nuclear antigen (PCNA) antibody shows a negligible number of cells stained in normal liver, but much higher numbers in regenerating liver 24 and 48 h after surgery. We also verified different results by biochemical analysis. Two forms of PCNA, L type (eluted at low concentrations of KCl from a phosphocellulose column) and H type (eluted at high KCl concentrations), were observed in the nucleoplasm of regenerating livers 24 and 48 h after surgery. Treatment of the H type fraction with nuclease caused the H type to disappear and the amount of L type to increase. PCNAs in the cytoplasm are P type (eluted in the pass through fraction) and L type. Surprisingly, the total amounts of P type and L type in cytoplasmic extracts are comparable to those of L type and H type in the nucleoplasm. These results suggest that newly synthesized PCNA is immediately converted into the P and L complex forms. The P type and some of the L type that lacks a nuclear localization signal remain in the cytoplasm; the rest of the L type with a nuclear localization signal is transferred into the nuclei. Then, some of the L type in the nucleoplasm forms the H type, which binds to DNA. These three types of PCNA are also found in significant amounts in the nucleoplasm and cytoplasm of normal rat liver despite its nonproliferating state.
Tanno
M
M
Department of Nuclear Medicine and Radiological Sciences, Tokyo Metropolitan Geriatric Hospital, Japan.
Taguchi
T
T
D000818:Animals; D002467:Cell Nucleus / Q000276:immunology; D003593:Cytoplasm / Q000276:immunology; D007150:Immunohistochemistry; D008099:Liver / Q000276:immunology*; D008115:Liver Regeneration / Q000276:immunology*; D008297:Male; D018809:Proliferating Cell Nuclear Antigen / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D018809:Proliferating Cell Nuclear Antigen