Abstract

The two vegetative cell types of the acellular slime mould Physarum polycephalum ‐ amoebae and plasmodia ‐ differ greatly in cellular organisation and behaviour as a result of differences in gene expression. The development of uninucleate amoebae into multinucleate, syncytial plasmodia is under the control of the mating‐type locus matA, which is a complex, multi‐functional locus. A key period during plasmodium development is the extended cell cycle, which occurs in the developing uninucleate cell. During this long cell cycle, many of the changes in cellular organisation that accompany development into the multinucleate stage are initiated including, for example, alterations in microtubule organisation. Genes have been identified that show cell‐type specific expression in either amoebae or plasmodia and many of these genes alter their pattern of expression during the extended cell cycle. With the introduction of a DNA transformation system for P. polycephalum, it is now possible to investigate the functions of genes in the vegetative cell types and their roles in the cellular reorganisations accompanying development.