Growth-related expression of the ectonucleotide pyrophosphatase PC-1 in rat liver.
Plasma cell differentiation antigen-1 (PC-1) is a 5'-ectonucleotide pyrophosphatase that has been implicated in various processes including insulin- and nucleotide-mediated signaling and cell growth. We show here that the expression of both PC-1 mRNA and protein in rat liver and in hepatoma cells is strictly growth-related. Thus, the level of PC-1 in FAO hepatoma cells increased with the cell density. PC-1 was not expressed in the neonatal rat liver, but gradually appeared in the first weeks of age, to reach adult levels around the weaning period. Furthermore, PC-1 protein and mRNA largely disappeared from the liver within 24 hours following a hepatectomy of 70%, but re-appeared in the later phases (3-15 days) of the ensuing regeneration period. An equally rapid loss of PC-1 protein and mRNA could also be provoked in normal livers by the administration of the translational inhibitor, cycloheximide, but the transcriptional inhibitors, actinomycin D and alpha-amanitin, did not show these effects. Nuclear run-on assays revealed that the loss of PC-1 mRNA after hepatectomy or after the administration of cycloheximide was not caused by a decreased transcription of the PC-1 gene, suggesting that the level of PC-1 is controlled by an mRNA-stabilizing protein that is lost after hepatectomy and has a high turnover.
Stefan
C
C
Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, Belgium.
Stalmans
W
W
Bollen
M
M
D000375:Aging / Q000378:metabolism; D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology; D006498:Hepatectomy; D008099:Liver / Q000254:growth & development* / Q000378:metabolism*; D011184:Postoperative Period; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013347:Subcellular Fractions / Q000201:enzymology; D014407:Tumor Cells, Cultured
D000944:Antigens, Differentiation, B-Lymphocyte; D011500:Protein Synthesis Inhibitors