Using the rapidly evolving technology of fluorescent microscopy, researchers at the University of California, Davis, recently became the first to see tiny motor proteins carry cargoes through a live animal cell.
The researchers, in the laboratory of cell biologist Jonathan Scholey, watched motor proteins tagged with fluorescent green markers as they quickly and methodically towed large molecules from one end of a roundworm cilium to the other. On single-celled animals, the short, hairlike cilia act like oars to propel the animal through watery environments; inside multi-celled animals like worms, cilia move fluids around and act as sensing centers.
In this experiment, the cilia were located at the tip of a nerve cell inside the head of a roundworm. These cilia's job is to identify chemicals that indicate food or toxic materials -- rather like the task of a human's nose -- and trigger a response. The motor proteins' cargo were probably signaling components and building materials for cilia maintenance, the researchers said.
"Being able to actually see what happens inside the cilia should help us learn more about the proteins in that transportation system and about the genes that produce them," Scholey said. "Our results also demonstrate a technical method that other researchers could use."
The research was funded by the National Institutes of Health and is described in correspondence to this Thursday's issue of the journal Nature. The authors are Jose Orozco, postgraduate researcher and technician; Karen Wedaman, senior research associate and technician; graduate student Dawn Signor; postgraduate researcher Heather Brown; and Scholey. An additional author, UC Davis developmental biologist Lesilee Rose, provided expertise in using the roundworms, C. elegans, in the experiment.