THE SHAPE OF THINGS TO COME - MORPHOGENESIS IN YEAST AND RELATED PATTERNS IN OTHER SYSTEMS

The elaboration of cell form has fascinated biologists for generations . A vast body of literature details the life cycles, anatomy, and deve lopmental programs of many species. The mechanisms responsible for the observed diversity of structure involve polarization, directed growth , and spatial memory. These issues of morphogenesis are currently unde r study in the budding yeast Saccharomyces cerevisiae and other fungi. In yeast, a number of genes are known that specifically affect either the orientation or the assembly of a polarity axis. These include the bud-site selection genes, BUD1-BUD5, as well as the polarity establis hment genes, CDC24, CDC42, CDC43, and BEM1. Members of each of these c lasses encode elements in signal transduction type pathways. This revi ew examines our present understanding of the molecular machinery respo nsible for orienting and assembling cell polarity as best understood i n S. cerevisiae, and speculates about how similar machinery might func tion in other fungi.