The Journal of Neuroscience, June 1, 2002, 22(11):4293-4301
Transport of Neuronal BC1 RNA in Mauthner Axons
Ilham A.
Muslimov1,
Margaret
Titmus3,
Edward
Koenig3, and
Henri
Tiedge1, 2
Departments of 1 Physiology and Pharmacology and
2 Neurology, State University of New York, Health Science
Center at Brooklyn, Brooklyn, New York 11203, and
3 Department of Physiology and Biophysics, State University
of New York at Buffalo, Buffalo, New York 14214
In neurons, localized RNAs have been identified in dendrites and
axons; however, RNA transport in axons remains poorly understood. Here
we analyzed axonal RNA transport in goldfish Mauthner neurons in
vivo. BC1 RNA, a noncoding RNA polymerase III transcript that is targeted to dendrites in neurons of the rodent nervous system, was
used as a probe for axonal RNA transport. Somata of Mauthner neurons
were microinjected with various RNAs. Full-length BC1 RNA, but not
control RNAs of similar length, was targeted to both axons and
dendrites of Mauthner neurons. BC1 RNA was transported in the form of a
rapidly advancing wave front that progressed along axons, in a
microtubule-dependent manner, at a rate of 2 µm/sec. Whereas a BC1 5'
segment of 65 nucleotides was transported to axons and dendrites in a
way indistinguishable from full-length BC1 RNA, a BC1 3' segment of 60 nucleotides did not enter Mauthner cell processes to any significant
extent. In the wake of the wave advancing through the axon, BC1 RNA was
found localized to discrete, spatially delimited domains at the axonal
surface. Such demarcated cortical concentrations of BC1 RNA could not
be observed after disruption of F-actin organization in the axon. It is
concluded that the specific delivery of BC1 RNA to spatially defined
axonal target sites is a two-step process that requires the sequential participation of microtubules for long-range axial transport and of
actin filaments for local radial transfer and focal accumulation in
cortical domains.
Key words:
fast axonal transport; RNA localization; targeting
element; axons; Mauthner neurons; microinjection
Copyright © 2002 Society for Neuroscience 0270-6474/02/22114293-09$05.00/0
Previous Article | Next Article
