Tumour suppressor protein p53 released by nuclease digestion increases at the onset of rat liver regeneration

The effect of Triaenophorus nodulosus (Cestoda: Bothriocephalidea) infection on some biochemical parameters of the liver of Perca fluviatilis

Natural infection of 2 to 6-year-old perch with the cestode parasites Triaenophorus nodulosus was shown to have minor effects on the studied components of the antioxidant defense system, nucleic acids degradation, and carbohydrate metabolism enzymes in the liver of the fish. The level of infection of 1-4 parasite larvae per fish observed in wild population of perch was shown to be moderate in terms of its effect on the health of the host fish. The activity of hepatic enzymes β-galactosidase, β-glucosidase, cathepsin D, and glutathione S-transferase showed different responses in infected males and females, which indicates different potential resistance of fish to the stress exposure between genders.

Expressed genes in regenerating rat liver after partial hepatectomy

AIM: To reveal the liver regeneration (LR) and its control as well as the occurrence of liver disease and to study the gene expression profiles of 551 genes after partial hepatectomy (PH) in regenerating rat livers.

METHODS: Five hundred and fifty-one expressed sequence tags screened by suppression subtractive hybridization were made into an in-house cDNA microarray, and the expressive genes and their expressive profiles in regenerating rat livers were analyzed by microarray and bioinformatics.

RESULTS: Three hundred of the analyzed 551 genes were up- or downregulated more than twofolds at one or more time points during LR. Most of the genes were up- or downregulated 2-5 folds, but the highest reached 90 folds of the control. One hundred and thirty-nine of them showed upregulation, 135 displayed downregulation, and up or down expression of 26 genes revealed a dependence on regenerating livers. The genes expressed in 24-h regenerating livers were much more than those in the others. Cluster analysis and generalization analysis showed that there were at least six distinct temporal patterns of gene expression in the regenerating livers, that is, genes were expressed in the immediate early phase, early phase, intermediate phase, early-late phase, late phase, terminal phase.

CONCLUSION: In LR, the number of down-regulated genes was almost similar to that of the upregulated genes; the successively altered genes were more than the rapidly transient genes. The temporal patterns of gene expression were similar 2 and 4 h, 12 and 16 h, 48 and 96 h, 72 and 144 h after PH. Microarray combined with suppressive subtractive hybridization can effectively identify the genes related to LR.

Persistent nuclear accumulation of protein kinase CK2 during the G1-phase of the cell cycle does not depend on the ERK1/2 pathway but requires active protein synthesis

Protein kinase CK2 and phosphorylated ERK1/2 accumulated in nucleus after serum stimulation of quiescent HepG2 cells. Nonetheless, phospho-ERK1/2 accumulated mainly in the nuclease-extracted fraction (NE) whereas the increases in nuclear CK2 (either CK2alpha or CK2beta) occurred initially in the nuclease-resistant fraction (NR). Transient decreases in CK2 were observed in cytoplasm and NE in the first 3h but thereafter they either reverted (cytoplasm) or increased above the control (NE). CK2 levels in both NE and NR were high in cells arrested at G1/S. Maximal nuclear accumulation of CK2 was blocked by cycloheximide but little affected by PD98059, SB203580 or apigenin, all of which affected nuclear phopho-ERK1/2. Thus, nuclear accumulation of CK2 during G1 phase is independent of ERK1/2 pathway. Although this process may initially relay on intracellular redistribution of the preexisting enzyme, active protein synthesis is required to attain maximal nuclear CK2 levels.