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AXONAL MIGRATION OF VARIOUS RIBONUCLEIC ACID SPECIES ALONG THE OPTIC TRACT OF THE CHICK 1
Author(s) -
Bondy S. C.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb06221.x
Subject(s) - rna , axon , axoplasmic transport , ribosome , biology , optic tract , uridine , optic nerve , microbiology and biotechnology , ribosomal rna , biochemistry , cytoplasm , biophysics , anatomy , gene
—The avian visual system has been used to study the axonal transport of RNA and protein. After monocular injection of radioactive uridine into 1‐day‐old chicks, a considerable amount of labelled RNA migrated along the optic tract to the optic tectum contralateral to the injected eye. This RNA was largely ribosomal, although it was contained in several subcellular fractions. The migration of RNA appeared to be a slow process. However, following monocular injection of radioactive proline, the migration of ribosomal protein was rapid. This discrepancy was resolved by examination of the kinetics of labelling of RNA and protein within the retina after intraocular injection of a mixture of labelled uridine and proline. Cytoplasmic RNA was labelled much more slowly than cytoplasmic protein. This lag in labelling of RNA could account for the delayed arrival of RNA at the contralateral optic lobe and suggests that ribosomes may travel rapidly along the axon. In other experiments, eyes were removed 4 days after the injection of labelled precursors. After a further 14 days, the remaining radioactivity in RNA and protein of contralateral optic lobes was 5–15% of that attributable to migration along the axon in control, unenucleated birds. Thus, the survival of the bulk of migrating macromolecules depends on the integrity of synaptic terminals. This observation suggests that both RNA and protein migrate within the axon rather than extra‐axonally, and that they remain largely within the nerve cells along the axons of which they are transported.