Differential-display analysis of gene expression in livers from normal and partially hepatectomized mice

Partial hepatectomy, resulting in the removal of approximately 70% of the liver, is widely utilized for studies of liver growth in experimental animals. The regenerative response is proportional to the amount of liver removed. Knowing when and where genes are expressed provides a strong clue as to its biological role. The RNA differential-display (DD) technique facilitates monitoring the differential expression of a large number of activated or suppressed genes under various biological conditions. To reveal mechanisms of liver regeneration, we performed a comparative analysis of gene expression during liver regeneration using DD. We sacrificed male Balb/c mice, aged 10 to 12 weeks, at 0, 24, 48, and 72 hours, and 1 and 2 weeks after PHx. The livers were weighed, and the amount of glutamic-oxaloacetate transaminase in serum measured. We extracted the total RNA from frozen liver tissue and confirmed the RNA quality using a lab-chip system. DD analysis was performed essentially as described by Liang and Pardee. Semiquantitative reverse-transcription polymerase chain reaction was performed to confirm the results of DD analysis. Of the 56 fragments that exhibited changed expression levels during PHx, 39 were cloned and sequenced. There were 31 known genes, 13 unknown genes, and 9 expressed-sequence tags. These results indicated that DD is a powerful approach for monitoring molecular events in the regenerating liver.