Models for oxygen sensing in yeast: implications for oxygen-regulated gene expression in higher eucaryotes.

Adaptation to changes in oxygen tension in cells, tissues, and organisms depends on changes in the level of expression of a large and diverse set of proteins. It is likely that most cells and tissues possess an oxygen sensing apparatus and signal transduction pathways for regulating expression of oxygen-responsive genes. Although progress has been made in understanding the transcriptional machinery involved in oxygen-regulated gene expression of eucaryotic genes the underlying mechanism(s) of oxygen sensing and the signaling pathways that connect oxygen sensor(s) to the transcription machinery of eucaryotes are still poorly understood. The yeast Saccharomyces cerevisiae is ideal for addressing these problems. Indeed, it is well-suited for broadly based studies on oxygen sensing at the cellular level because it lends itself well to genetic and biochemical studies and because its genome has been completely sequenced. This review focuses on oxygen-regulated gene expression and current models for oxygen sensing in this yeast and then considers their applicability for understanding oxygen sensing in mammals.