The long range objectives of this study are to characterize molecules associated with the microtubules of eukaryotic flagella that are responsible for the function and assembly of these organelles. The study is based on application of morphological, genetical, and biochemical techniques to a model organism, the unicellular alga Chlamydomonas reinhardtii. Mutant strains under analysis include those affecting flagellar function and assembly. A subset of assembly mutants are clustered on a linkage group showing unique meiotic behavior. In one class of these, the uni mutants, the defect appears to interrupt assembly of the basal body transition zone. Efforts will be made to identify a cellular DNA encoding these functions. Independent efforts will be made to obtain genomic clones encoding the several large subunit polypeptides of four axonemal dyneins. Phosphorylation of a set of polypeptides involved in controlling transitions between two different bending forms of flagella will be studied using in vitro phosphorylation methods as well as reversion analysis of mutants. The latter technique will also be used to study components required for stability of central microtubules.
