Davis,
CA (4/23/99)- A new fluorescent microscopy technique for the first time
reveals the workings of cellular motors as they ferry their cargo through
living cells.
Special proteins, sometimes called
cellular motors, perform an essential role in the formation and maintenance
of cellular cilia, which perform many important functions in various cell
and tissue types. One such protein, kinesin-II, delivers cargoes of macromolecular
complexes, called 'rafts', in one direction along microtubules. Another motor
protein, dynein, returns the rafts to their point of origin.
left- Worm
head with schematic of C. elegans chemosensory cilia. info
Researchers at the University
of California, Davis, developed a method for filming the microscopic action
of these cellular motors. They stained the motors with green fluorescent protein
and recorded their travels along sensory cilia in chemosensory neurons in
living roundworms, Caenorhabditis elegans. This is the first time intracellular
transport of a motor and its cargo have ever been recorded in a living system.
The cilia visualized in this experiment
were a type found on tip of a nerve cell inside the head of a roundworm. These
cilia identify chemicals that differentiate food and toxic materials. The
motor proteins deliver 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. Our results also
demonstrate a technical method that other researchers could use," said Jonathan
M. Scholey, Ph.D., Professor of Cell Biology, UC Davis.
The term cilia derives from the
Latin word for eyelash. Besides the sensory cilia studied in this experiment,
several other types of cilia are found in living organisms. Motile cilia help
to drive the swimming of cells and embryos. Nodal cilia generate left-right
asymmetry in vertebrate embryos.
The research appears in the April
22, 1999 issue of Nature.
Copyright 1999© Info
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