Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.13.1 (exoribonuclease)
 732 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our understanding of the highly specialized functions for small non-coding single-stranded RNA (ssRNA) in the transcriptome of the human central nervous system (CNS) continues to evolve. Circular RNAs (circRNAs), a recently discovered class of ssRNA enriched in the brain and retina, are extremely stable and intrinsically resilient to degradation by exonuclease. Conventional methods of ssRNA, microRNA (miRNA), or messenger RNA (mRNA) detection and quantitation requiring free ribonucleotide ends may have considerably underestimated the quantity and significance of CNS circRNA in the CNS. Highly-specific small ssRNAs, such as the ~23 nucleotide (nt) Homo sapien microRNA-7 (hsa-miRNA-7; chr 9q21.32), are not only abundant in the human limbic system but are, in addition, associated with a ~1400 nt circRNA for miRNA-7 (ciRS-7) in the same anatomical region. Structurally, ciRS-7 contains about ~70 tandem anti-miRNA-7 sequences and acts as an endogenous, anti-complementary miRNA-7 "sponge" that attracts, binds, and, hence, quenches, natural miRNA-7 functions. Using a combination of DNA and miRNA array technologies, enhanced LED-Northern and Western blot hybridization, and the magnesium-dependent exoribonuclease and circRNA-sensitive probe RNaseR, here we provide evidence of a significantly misregulated ciRS-7-miRNA-7-UBE2A circuit in sporadic Alzheimer's disease (AD) neocortex (Brodmann A22) and hippocampal CA1. Deficits in ciRS-7-mediated "sponging events", resulting in excess ambient miRNA-7 appear to drive the selective down-regulation in the expression of miRNA-7-sensitive mRNA targets, such as that encoding the ubiquitin conjugating enzyme E2A (UBE2A; chr Xq24). UBE2A, which normally serves as a central effector in the ubiquitin-26S proteasome system, coordinates the clearance of amyloid peptides via proteolysis, is known to be depleted in sporadic AD brain and, hence, contributes to amyloid accumulation and the formation of senile plaque deposits. Dysfunction of circRNA-miRNA-mRNA regulatory systems appears to represent another important layer of epigenetic control over pathogenic gene expression programs in the human CNS that are targeted by the sporadic AD process.
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PMID:Deficiency in the Ubiquitin Conjugating Enzyme UBE2A in Alzheimer's Disease (AD) is Linked to Deficits in a Natural Circular miRNA-7 Sponge (circRNA; ciRS-7). 2792 95

mRNA turnover controls gene expression under various conditions in aging and neurodegenerative diseases. Polyglutamine (polyQ) diseases and intranuclear inclusion body disease (INIBD) are neurodegenerative diseases characterized by the formation of nuclear inclusions. These inclusions are immunopositive for several proteins associated with amyotrophic lateral sclerosis. In amyotrophic lateral sclerosis, the processing of RNA from gene transcription through degradation (RNA metabolism) has been reported to be altered. We hypothesized that the proteins associated with RNA metabolism are also involved in the formation of nuclear inclusions in polyQ diseases and INIBD. 3'-5' exoribonuclease DIS3L2 and 5'-3' exoribonuclease XRN1 play critical roles in mRNA decay. Using immunohistochemistry with antibodies against DIS3L2 and XRN1, we examined the brains of patients with polyQ diseases and INIBD and normal control subjects. In controls, immunoreactivity for DIS3L2 and XRN1 was found in the neuronal cytoplasm and neuropil, respectively. In INIBD, immunoreactivity for DIS3L2 and XRN1 was present in neuronal and glial nuclear inclusions. Co-localization of ubiquitin and DIS3L2 or XRN1 was demonstrated in these inclusions. In polyQ diseases, however, nuclear inclusions were immunonegative for DIS3L2 and XRN1. These findings suggest that sequestration of exoribonucleases to nuclear inclusions may be related to the pathogenesis of INIBD.
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PMID:Immunohistochemical localization of exoribonucleases (DIS3L2 and XRN1) in intranuclear inclusion body disease. 2910 Aug 4