Role of the Basal Body in Axoneme Assembly

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

Scientific research Cilia are highly conserved organelles present in all major phylogenetic groups of eukaryotic organisms. They have been adapted for motility of single cells and for fluid transport over cell layers. In multicellular animals, they play specialized roles in embryo development and in signaling pathways in diverse cell types. The nine doublet microtubules in typical cilia grow from a template of nine triplet microtubules that compose the wall of the basal body (centriole). Basal body docking with the plasma membrane provides a site for assembly of a cilium. Components of intraflagellar transport, required for ciliary assembly and maintenance, converge at the basal body. Initiation of ciliary assembly depends on the conversion of triplet microtubules to doublet microtubules at the distal end of the basal body. Using as a model system the unicellular, biflagellate green alga Chlamydomonas reinhardtii, this project investigates a class of "uni" mutants with defects in docking of basal bodies with the plasma membrane and in the conversion of triplet microtubules to doublet microtubules required for ciliary assembly. The molecular basis of these processes is investigated through biochemical characterization of the products of the UNI1 and UNI2 genes. The role of phosphorylation in the function of the Uni2 protein is being studied. The functions of the Uni1 and Uni2 proteins are being examined through analysis of mutant phenotypes, subcellular localization of the proteins, and protein interactions. Broader Impacts This project integrates research and education by providing mentored research experiences for undergraduate students. Students receive training in cell biology, molecular biology, and genetics disciplines while carrying out research. The projects help students to develop the ability for critical thinking and the skills for written and oral science communication.