The major objective of this proposal is to analyze the mechanisms by which spatial patterns are generated and maintained in the cell surface layer (cortex) of a complex eukaryotic cell, Tetrahymena thermophila. Emphasis will be placed on the patterning of ciliary units within the oral apparatus, with investigation of the respective roles of local mechanisms of pattern-generation (cytotaxis) and global influenes (positional information). Major methods to be used are the generation and genetic analysis of genic pattern-mutants, and the detailed study of cortical phenotypes employing protein-silver (protargol) staining. The positioning and internal patterning of the oral apparatus are to be analyzed in detail in existing pattern-mutants, in new mutants to be generated, and in some cases also in double homozygotes. The effects of a 180 degree- rotation of existing ciliary rows upon details of oral development will be examined in normal cells and in a mutant (janus) that brings about reversal of a global pattern. The influence of longitudinal microtubule and bands (LMs) will be subjected to special scrutiny, including an examination of effects of extra LMs interposed between ciliary row to test a hypothesis that these bands mark the borders of cortical compartments. Two new methods of genetic manipulation in Tetrahymena, induction of self-fertilization (cytogamy) and manipulation of nullisomics, are to be employed to assist in bringing new mutants to expression. A special effort will be made to induced and recognize new mutations similar to the most interesting of the existing pattern-mutants, janus.
