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Updated: Aug 2, 2026
Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration
Published on: March 17, 2014
FMRP and MOV10 regulate Dicer1 expression and dendrite development
Monica C Lannom1, Joshua Nielsen2, Aatiqa Nawaz1
1Cell and Developmental Biology, University of Illinois, Urbana, Illinois, United States of America.
Abstract:
Fragile X syndrome results from the loss of expression of the Fragile X Mental Retardation Protein (FMRP). FMRP and RNA helicase Moloney Leukemia virus 10 (MOV10) are important Argonaute (AGO) cofactors for miRNA-mediated translation regulation. We previously showed that MOV10 functionally associates with FMRP. Here we quantify the effect of reduced MOV10 and FMRP expression on dendritic morphology. Murine neurons with reduced MOV10 and FMRP phenocopied Dicer1 KO neurons which exhibit impaired dendritic maturation Hong J (2013), leading us to hypothesize that MOV10 and FMRP regulate DICER expression. In cells and tissues expressing reduced MOV10 or no FMRP, DICER expression was significantly reduced. Moreover, the Dicer1 mRNA is a Cross-Linking Immunoprecipitation (CLIP) target of FMRP Darnell JC (2011), MOV10 Skariah G (2017) and AGO2 Kenny PJ (2020). MOV10 and FMRP modulate expression of DICER1 mRNA through its 3'untranslated region (UTR) and introduction of a DICER1 transgene restores normal neurite outgrowth in the Mov10 KO neuroblastoma Neuro2A cell line and branching in MOV10 heterozygote neurons. Moreover, we observe a global reduction in AGO2-associated microRNAs isolated from Fmr1 KO brain. We conclude that the MOV10-FMRP-AGO2 complex regulates DICER expression, revealing a novel mechanism for regulation of miRNA production required for normal neuronal morphology.
Insights
Fragile X syndrome is linked to reduced expression of Fragile X Mental Retardation Protein (FMRP). This study reveals FMRP and MOV10 regulate DICER1 expression, impacting miRNA production and neuronal development.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Fragile X syndrome (FXS) is caused by reduced Fragile X Mental Retardation Protein (FMRP) expression.
- FMRP and MOV10 (RNA helicase Moloney Leukemia virus 10) are crucial cofactors in miRNA-mediated translation regulation.
- Previous work established a functional association between MOV10 and FMRP.
Purpose of the Study:
- To quantify the impact of reduced MOV10 and FMRP expression on dendritic morphology.
- To investigate the hypothesis that MOV10 and FMRP regulate DICER1 expression.
- To elucidate the molecular mechanism by which MOV10, FMRP, and AGO2 control miRNA production in neurons.
Main Methods:
- Comparative analysis of dendritic morphology in murine neurons with reduced MOV10/FMRP versus Dicer1 knockout neurons.
- Quantification of DICER1 expression in cells and tissues with altered MOV10 or FMRP levels.
- Cross-linking immunoprecipitation (CLIP) assays to identify Dicer1 mRNA as a target of FMRP, MOV10, and AGO2.
- Functional rescue experiments using a DICER1 transgene in Mov10 knockout neuroblastoma cells and heterozygote neurons.
- Analysis of AGO2-associated microRNAs in Fmr1 knockout brain tissue.
Main Results:
- Reduced MOV10 and FMRP expression in neurons phenocopied Dicer1 knockout neurons, showing impaired dendritic maturation.
- DICER1 expression was significantly reduced in cells and tissues with decreased MOV10 or FMRP.
- Dicer1 mRNA was confirmed as a CLIP target for FMRP, MOV10, and AGO2, with regulation occurring via the 3'UTR.
- Introduction of a DICER1 transgene restored normal neurite outgrowth and branching in relevant cellular models.
- A global reduction in AGO2-associated microRNAs was observed in Fmr1 knockout brains.
Conclusions:
- The MOV10-FMRP-AGO2 complex plays a critical role in regulating DICER1 expression.
- This regulation is essential for normal miRNA production and neuronal morphology.
- This study uncovers a novel molecular mechanism contributing to the pathophysiology of Fragile X syndrome.
