Discovery of a Suppressor of ADF1 and the Mapping of a new ADF gene, ADF2, in Chlamydomonas reinhardtii

Eukaryotic cilia are evolutionary conserved microtubule-based organelles that play important roles in cell signalling, development and motility. Cilia can be shed through a process known as deflagellation, in which the cilium is severed at a specific site at its base in response to a stress signal, through calcium signalling. Fifteen years ago three genes were uncovered in a screen for deflagellation mutants, two of which were cloned and their roles in the microtubule-severing event characterized. The third gene, named ADF1 has to date eluded identification. A previous graduate student genetically mapped ADF1 to Linkage Group (Chromosome) IX to identify the ADF1 gene. I tried, unsuccessfully, to rescue the adf1 mutation with wild type DNA from the gene locus. In the rescue attempts I recovered a potential suppressor of the adf1-3 mutant. Despite the many attempts I was unable to rescue adf1 or identify the flanking DNA of the adf1-3 suppressor. Since no MT severing protein or calcium sensor were recovered in the original genetic screen a second genetic screen is being carried out, this time for conditional deflagellation mutants. From this screen I characterized a new acid induced deflagellation gene, ADF2, and mapped it to Linkage Group III. The work in this thesis thus contributes new information about two previously unknown deflagellation genes, ADF2 and ADF1-Suppressor.