[The characteristics of PSCL32.5 protein from Physarum polycephalum and the variation of the content through cell cycle].

Crude fraction of Arg/Ser-rich proteins (SR proteins) were isolated from plasmodia of Physarum polycephalum and immunoassayed by western blot with a monoclonal antibody against SC35 protein from HeLa cell. Two polypeptides were detected by the antibody, suggesting that they were SCL(SC35-like) proteins. The SCL proteins have their mass weight of 32.5 kD and 82.5 kD, respectively, and so were termed PSCL32.5 and PSCL82.5 in this paper. The PI of PSCI32.5 was ascertained as 6.19 by IEF after a further purification of the protein with SDS-PAGE. The densitometric scanning of the western blot bands of PSCI32.5 isolated at different phases of cell cycle of P. polycephalum demonstrated that the relative content of the protein varied through the cell cycle: it appeared as the lowest at early S phase, showed increases from S phase to G2 phase, and peaked at late G2 phase.