3' untranslated region in a light neurofilament (NF-L) mRNA triggers aggregation of NF-L and mutant superoxide dismutase 1 proteins in neuronal cells.

Abstract

The pathogenesis of neurodegenerative diseases is believed to involve abnormal aggregation of proteins, but the mechanisms initiating protein aggregation are unclear. Here we report a novel phenomenon that could be instrumental in triggering protein aggregation in neurodegenerative diseases. We show that the 3' untranslated region (3'UTR) of a light neurofilament (NF-L) transcript enhances the reactivity of its own translated product and leads to loss of solubility and aggregation of NF-L protein and to coaggregation of mutant superoxide dismutase 1 (SOD1) protein. Full-length mouse NF-L cDNAs, with and without NF-L 3'UTR, were fused to the C terminus of a green fluorescent protein (GFP) reporter gene, and the GFP-tagged NF-L proteins were examined in transfected Neuro2a cells. The GFP-tagged NF-L protein expressed from the transgene containing NF-L 3'UTR, but not from the transgene lacking NF-L 3'UTR, colocalizes with endogenous heavy neurofilament protein and, at high-level expression, leads to loss of solubility and aggregation of GFP-tagged NF-L protein. Aggregation of GFP-tagged NF-L protein triggers coaggregation and loss of solubility of coexpressed DsRed-tagged mutant (G93A) SOD1 protein but not wild-type SOD1 protein. Deletional mutagenesis maps the RNA sequence causing aggregation of GFP-tagged NF-L protein to the proximal 45 nucleotides of NF-L 3'UTR. This is the site of a major destabilizing element in NF-L RNA and binding site for RNA-binding proteins. Our findings support a working model whereby NF-L RNA, or cognate RNA-binding factors, enhances the reactivity of NF-L protein and provides a triggering mechanism leading to aggregation of NF-L and other proteins in neurodegenerative diseases.

• Authors: Hong Lin, Jinbin Zhai, Rafaela Cañete-Soler, William W Schlaepfer
• Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci) Vol. 24 Issue 11 Pg. 2716-26 (Mar 17 2004) ISSN: 1529-2401 [Electronic] United States
• PMID: 15028764 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• 3' Untranslated Regions
• Heat-Shock Proteins
• Luminescent Proteins
• Macromolecular Substances
• Neurofilament Proteins
• RNA, Messenger
• Receptors, Androgen
• Recombinant Fusion Proteins
• Ubiquitins
• neurofilament protein L
• neurofilament protein H
• Green Fluorescent Proteins
• SOD1 G93A protein
• Sod1 protein, mouse
• Superoxide Dismutase
• Superoxide Dismutase-1

Topics

• 3' Untranslated Regions (pharmacology, physiology)
• Animals
• Cell Line
• Genes, Reporter (genetics)
• Green Fluorescent Proteins
• Heat-Shock Proteins (metabolism)
• Luminescent Proteins (genetics)
• Macromolecular Substances
• Mice
• Neuroblastoma (metabolism)
• Neurodegenerative Diseases (etiology, metabolism)
• Neurofilament Proteins (genetics, metabolism)
• Neurons (drug effects, metabolism)
• Protein Binding (drug effects, genetics, physiology)
• RNA, Messenger (metabolism, pharmacology, physiology)
• Receptors, Androgen (genetics, metabolism)
• Recombinant Fusion Proteins (genetics, metabolism)
• Solubility
• Superoxide Dismutase (genetics, metabolism)
• Superoxide Dismutase-1
• Transfection
• Transgenes
• Trinucleotide Repeat Expansion
• Ubiquitins (metabolism)