An expanded G4C2 hexanucleotide repeat in the proximal regulatory region of C9orf72 is a frequent cause of neurodegenerative diseases in the frontotemporal lobar degeneration (FTLD) and motor neuron disease (MND) spectrum. Although primarily characterized by variably abundant pathological inclusions of TDP-43 protein, the lesion load was extended to TDP-43-negative, p62-positive neuronal and glial inclusions in extended regions of the central nervous system (CNS), particularly in cerebellum, where they may be characteristic of a C9orf72 repeat expansion. Disease mechanisms associated with repeat expansion disorders, including haploinsufficiency, RNA toxicity, and abnormal translation of expanded repeat sequences, are beginning to emerge. We review genetic, clinical, and pathological highlights and discuss current insights into the biology of this novel type of repeat expansion disease.
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http://dx.doi.org/10.1016/j.tins.2013.04.010 | DOI Listing |
Int J Mol Sci
December 2024
Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
(Fragile X messenger ribonucleoprotein 1), located on the X-chromosome, encodes the multi-functional FMR1 protein (FMRP), critical to brain development and function. Trinucleotide CGG repeat expansions at this locus cause a range of neurological disorders, collectively referred to as Fragile X-related conditions. The most well-known of these is Fragile X syndrome, a neurodevelopmental disorder associated with syndromic facial features, autism, intellectual disabilities, and seizures.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Co-Innovation Center for Sustainable Forestry in Southern China, College of Life Science, Nanjing Forestry University, Nanjing 210037, China.
is a member of the Styracaceae family, which is well-known for its remarkable ornamental and medicinal properties. In this research, we conducted comparative analysis of the chloroplast genomes from four samples of representing . The results demonstrated that the chloroplast genome of four samples ranging from 157,103 bp to 158,357 bp exhibited a typical quadripartite structure, including one large single-copy (LSC) region (90,131 bp to 90,342 bp), one small single-copy (SSC) region (18,467 bp to 18,785 bp), and two inverted repeat regions (IRs) (24,115 bp to 24,261 bp).
View Article and Find Full Text PDFGenetics
January 2025
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA.
Mismatch repair (MMR) is a highly conserved DNA repair pathway that recognizes mispairs that occur spontaneously during DNA replication and coordinates their repair. In Saccharomyces cerevisiae, Msh2-Msh3 and Msh2-Msh6 initiate MMR by recognizing and binding insertion deletion loops (in/dels) up to ∼ 17 nucleotides (nt.) and base-base mispairs, respectively; the two complexes have overlapping specificity for small (1-2 nt.
View Article and Find Full Text PDFThe most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) is an intronic GC repeat expansion in C9orf72. The repeats undergo bidirectional transcription to produce sense and antisense repeat RNA species, which are translated into dipeptide repeat proteins (DPRs). As toxicity has been associated with both sense and antisense repeat-derived RNA and DPRs, targeting both strands may provide the most effective therapeutic strategy.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Bioengineering, The Grainger College of Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA.
An abnormal expansion of a GGGGCC (GC) hexanucleotide repeat in the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two debilitating neurodegenerative disorders driven in part by gain-of-function mechanisms involving transcribed forms of the repeat expansion. By utilizing a Cas13 variant with reduced collateral effects, we develop here a high-fidelity RNA-targeting CRISPR-based system for C9ORF72-linked ALS/FTD. When delivered to the brain of a transgenic rodent model, this Cas13-based platform curbed the expression of the GC repeat-containing RNA without affecting normal C9ORF72 levels, which in turn decreased the formation of RNA foci, reduced the production of a dipeptide repeat protein, and reversed transcriptional deficits.
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