Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome

The majority of the human genome is comprised of non-coding DNA, which frequently contains redundant microsatellite-like trinucleotide repeats. Many of these trinucleotide repeats are involved in triplet repeat expansion diseases (TREDs) such as fragile X syndrome (FXS). After transcription, the t...

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Main Authors: Karen Kelley, Shin-Ju E. Chang, Shi-Lung Lin
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Neural Plasticity
Online Access:http://dx.doi.org/10.1155/2012/104796
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author Karen Kelley
Shin-Ju E. Chang
Shi-Lung Lin
author_facet Karen Kelley
Shin-Ju E. Chang
Shi-Lung Lin
author_sort Karen Kelley
collection DOAJ
description The majority of the human genome is comprised of non-coding DNA, which frequently contains redundant microsatellite-like trinucleotide repeats. Many of these trinucleotide repeats are involved in triplet repeat expansion diseases (TREDs) such as fragile X syndrome (FXS). After transcription, the trinucleotide repeats can fold into RNA hairpins and are further processed by Dicer endoribonuclases to form microRNA (miRNA)-like molecules that are capable of triggering targeted gene-silencing effects in the TREDs. However, the function of these repeat-associated miRNAs (ramRNAs) is unclear. To solve this question, we identified the first native ramRNA in FXS and successfully developed a transgenic zebrafish model for studying its function. Our studies showed that ramRNA-induced DNA methylation of the FMR1 5′-UTR CGG trinucleotide repeat expansion is responsible for both pathological and neurocognitive characteristics linked to the transcriptional FMR1 gene inactivation and the deficiency of its protein product FMRP. FMRP deficiency often causes synapse deformity in the neurons essential for cognition and memory activities, while FMR1 inactivation augments metabotropic glutamate receptor (mGluR)-activated long-term depression (LTD), leading to abnormal neuronal responses in FXS. Using this novel animal model, we may further dissect the etiological mechanisms of TREDs, with the hope of providing insights into new means for therapeutic intervention.
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spelling doaj-art-05400d031dd44b518957f0b6d5e8334e2025-02-03T05:44:39ZengWileyNeural Plasticity2090-59041687-54432012-01-01201210.1155/2012/104796104796Mechanism of Repeat-Associated MicroRNAs in Fragile X SyndromeKaren Kelley0Shin-Ju E. Chang1Shi-Lung Lin2Division of Regenerative Medicine, WJWU & LYNN Institute for Stem Cell Research, 12145 Mora Drive, STE6, Santa Fe Springs, CA 90670, USADivision of Regenerative Medicine, WJWU & LYNN Institute for Stem Cell Research, 12145 Mora Drive, STE6, Santa Fe Springs, CA 90670, USADivision of Regenerative Medicine, WJWU & LYNN Institute for Stem Cell Research, 12145 Mora Drive, STE6, Santa Fe Springs, CA 90670, USAThe majority of the human genome is comprised of non-coding DNA, which frequently contains redundant microsatellite-like trinucleotide repeats. Many of these trinucleotide repeats are involved in triplet repeat expansion diseases (TREDs) such as fragile X syndrome (FXS). After transcription, the trinucleotide repeats can fold into RNA hairpins and are further processed by Dicer endoribonuclases to form microRNA (miRNA)-like molecules that are capable of triggering targeted gene-silencing effects in the TREDs. However, the function of these repeat-associated miRNAs (ramRNAs) is unclear. To solve this question, we identified the first native ramRNA in FXS and successfully developed a transgenic zebrafish model for studying its function. Our studies showed that ramRNA-induced DNA methylation of the FMR1 5′-UTR CGG trinucleotide repeat expansion is responsible for both pathological and neurocognitive characteristics linked to the transcriptional FMR1 gene inactivation and the deficiency of its protein product FMRP. FMRP deficiency often causes synapse deformity in the neurons essential for cognition and memory activities, while FMR1 inactivation augments metabotropic glutamate receptor (mGluR)-activated long-term depression (LTD), leading to abnormal neuronal responses in FXS. Using this novel animal model, we may further dissect the etiological mechanisms of TREDs, with the hope of providing insights into new means for therapeutic intervention.http://dx.doi.org/10.1155/2012/104796
spellingShingle Karen Kelley
Shin-Ju E. Chang
Shi-Lung Lin
Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome
Neural Plasticity
title Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome
title_full Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome
title_fullStr Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome
title_full_unstemmed Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome
title_short Mechanism of Repeat-Associated MicroRNAs in Fragile X Syndrome
title_sort mechanism of repeat associated micrornas in fragile x syndrome
url http://dx.doi.org/10.1155/2012/104796
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AT shinjuechang mechanismofrepeatassociatedmicrornasinfragilexsyndrome
AT shilunglin mechanismofrepeatassociatedmicrornasinfragilexsyndrome