Preliminary Study Using Rat Liver Regeneration Model Spectrum Of Cells In G0, G1 Phase Differential Proteomics

The transition from G0 phase to G1 phase of the cell cycle is a precisely-regulated progress, about which a lot has yet to be known. We employed 2/3 partial hepatectomy(PH) model of rat liver to analyze the proteomic patterns of the hepatocytes in the quiescent phase and proliferating phase and further, to study the G0/G1 transition mechanism.Cellular and nuclear protein extracts were prepared from liver cells in the G0 phase (6hr after sham operation) and G1 phase(6hr after PH), and then subject to two dimensional electrophoresis with immobilized pH 3-10 linear gradients for first-dimension separation. Analyzed by Melanie Software, 55 differentially expressed protein spots were recognized in 2D gels and among these, 37 spots were up-regulated after PH, 18 down-regulated. 43 proteins were identified by MALDI-QTOF-MS and MS/MS re-confirmation. And we discussed the roles that these proteins possibly play in liver regeneration and G0/G1 transition.As for low-Mw proteins that cannot easily be detected by 2D, we employed SELDI ProteinChip technique. H4,IMAC3,IMAC40,SAX and WCX chips were used for analysis of cellular protein extracts from liver cells in the G0 and G1 phases,SAX and WCX chips for nuclear and mitochondria compartments. 64 up-regulated and 37 down-regulated protein peaks were detected all together. Based on Mw, pI and other information offered by SELDI, we also searched the database for candidate proteins of these differential peaks, which facilitated the further identification and study.In addition, we made a successful attempt at post-digestion analysis method complementary to 2D with the combination of SELDI and MS. By this method, we further validated 5 differentially expressed proteins detected by 2D, and more importantly, we found two that 2D in our experiment failed to recognize.