The last six years have seen an impressive increase in our knowledge of the factors controlling the expression of liverspecific genes. The seminal papers are referred to below, and the reader can gain an overview of the various transcription factors and their inter-relationships from Tronche and Yaniv (1992) and from Kuo et al. (1992). Despite our greatly improved knowledge, many of the classical observations in the somatic cell genetics of differentiation are at best only partly understood. This Commentary will review those observations in the light of recent findings and examine some of the remaining problems in the context of the diversity of the physiological controls that are known to influence tissue-specific gene expression.
Tissue-specific genes are distinguished from ‘house-keeping’ genes not only by their tissue-specific pattern of expression: it is to be expected from their function that tissue-specific genes should additionally be subject to elaborate regulation by extracellular...
