Regulation of apoptosis-associated genes in the regenerating liver

The ability of the liver to regenerate remains a fascinating response to he patic injury. Ever since the Greek myth of Prometheus, efforts have been ma de to unravel the mechanisms involved in liver regeneration. The cellular p henomenon represents an orchestrated response to external stimuli followed by sequential changes in gene expression, cytokine production, and morpholo gic structure. The most popular experimental model is based on the surgical removal of two-thirds of the liver: The remnant lobes respond to the loss of mass and function with expression of immediate- and delay-early genes wh ich prime the cells for eventual progression through the cell cycle. The mo lecular events which trigger liver regeneration are now beginning to unfold . However, the control of liver regeneration and the events involved in reg ulating the three-dimensional growth of the organ remain poorly defined. It now appears that apoptosis probably plays a key role in fine tuning ire re generative response. The list of apoptosis-related gene products seems to g row regularly and includes both pro- and antiapoptotic factors. It is notew orthy that many of these genes are critical mediators of both apoptosis and cell replication. The factors involved in predicting which pathway they ch ose provide the basis for uncovering the secrets of organ growth-be it by l ife or by death.