BUILDING A PLASMODIUM - DEVELOPMENT IN THE ACELLULAR SLIME-MOLD PHYSARUM-POLYCEPHALUM

The two vegetative cell types of the acellular slime mould Physarum po lycephalum - amoebae and plasmodia - differ greatly in cellular organi sation and behaviour as a result of differences in gene expression. Th e development of uninucleate amoebae into multinucleate, syncytial pla smodia is under the control of the mating-type locus matA, which is a complex, multi-functional locus. A key period during plasmodium develo pment is the extended cell cycle, which occurs in the developing uninu cleate cell. During this long cell cycle, many of the changes in cellu lar organisation that accompany development into the multinucleate sta ge are initiated including, for example, alterations in microtubule or ganisation. Genes have been identified that show cell-type specific ex pression in either amoebae or plasmodia and many of these genes alter their pattern of expression during the extended cell cycle. With the i ntroduction of a DNA transformation system for Fl polycephalum, it is now possible to investigate the functions of genes in the vegetative c ell types and their roles in the cellular reorganisations accompanying development.