Gene expression in regenerating liver in relation to cell proliferation and stress

Abstract

When hepatocyte proliferation is stimulated in the liver by partial hepatectomy, messenger RNAs coding for fibrinogen, actin, c‐myc and topoisomerase I are rapidly accumulated. We distinguish an early phase of accumulation (0–3 h after partial hepatectomy) which is also observed after a sham operation for the four genes, and during inflammation produced by Freund's adjuvant in the case of fibrinogen and c‐myc genes. The hepatic response to inflammation appears therefore to mimic events characteristic of the G0/G1 transition, such as the accumulation of the c‐myc mRNA. The late phase of mRNA accumulation (beyond 3 h after partial hepatectomy) is typical of liver regeneration. The level of c‐myc mRNA is transiently increased (20‐fold over normal) 20 h after partial hepatectomy, that is, at the time of DNA synthesis. Topoisomerase‐I mRNA level increases between 3 and 24 h after partial hepatectomy (5‐10‐fold over normal). These results suggest that accumulation of c‐myc and topoisomerase‐I mRNAs is associated with DNA replication in regenerating liver. Copyright © 1989, Wiley Blackwell. All rights reserved