Journal ArticleDOI
Sedimentation analysis of ribonucleic acid extracted from isolated mauthner nerve fibre components
TLDR
Segments of spinal cords from goldfish or from carp were incubated in vitro in the presence of RNA precursors for varying periods of time to isolate Mauthner nerve fibres from the fresh unfixed tissue or from the fixed spinal cord.Abstract:
— Segments of spinal cords from goldfish or from carp were incubated in vitro in the presence of RNA precursors for varying periods of time. Mauthner nerve fibres were isolated from the fresh unfixed tissue, or, for the separate analyses of axon and myelin sheath, from the fixed spinal cord.
The myelinated Mauthner fibre isolated from the incubated spinal cord showed RNA synthesis. A considerable part of the material sedimented at 4S, but part of the nucleic acid was recovered at higher sedimentation values, up to 30S. Newly synthesized RNA was extracted from the isolated myelin sheath as well as from the axon. Isolated myelinated Mauthner fibres were also incubated in vitro with RNA precursors. In this case incorporation occurred exclusively in material sedimenting at 4S or lower. The turnover rate for RNA from the fibre was of a higher order than that of the bulk of RNA from the spinal cord. The findings of RNA synthesis in these tissue components lacking nuclei could possibly be explained as owing to mitochondria.
Studies by electron microscopy demonstrated the extent of purity of the isolated components and it was found that contamination was so small as to make it unlikely that the RNA investigated originated in contaminating tissue.read more
Citations
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Book ChapterDOI
Protein Transport in Neurons
TL;DR: Evidence supports the synthesis of some axonal proteins at the level of the axon, which has provided a plausible mechanism for an integration of the metabolism of the neuron and has broadened the understanding of the role of the neurons.
Journal ArticleDOI
Protein synthesis in axons and terminals: significance for maintenance, plasticity and regulation of phenotype. With a critique of slow transport theory.
TL;DR: This article focuses on local protein synthesis as a basis for maintaining axoplasmic mass, and expression of plasticity in axons and terminals, and proposes a distributed "sprouting program," which governs local plasticity of axons, is regulated by environmental cues, and ultimately depends on local synthesis.
Journal ArticleDOI
Axonal and presynaptic protein synthesis: new insights into the biology of the neuron.
TL;DR: It is demonstrated that extrasomatic translation sites, which are now well recognized in dendrites, are also present in axonal and presynaptic compartments.
Journal ArticleDOI
Analysis of axoplasmic RNA from invertebrate giant axons.
Raymond J. Lasek,Raymond J. Lasek,Carla Dabrowski,Carla Dabrowski,Ruth H. Nordlander,Ruth H. Nordlander +5 more
TL;DR: Protein synthesis seems unlikely in axoplasm from the giant axons of the polychaete, Myxicola and the squid, Loligo, as 4S RNA is present but little or no rRNA.
Journal ArticleDOI
Ribosomal RNA in Mauthner axon: implications for a protein synthesizing machinery in the myelinated axon.
TL;DR: Evidence was presented to support the contention that axonal rRNA was not due to contamination from the myelin sheath, and possible reasons for the lack of ultrastructural evidence for axoplasmic ribosomes are discussed.
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