Cell-specific RNA Targets of the Fragile X Mental Retardation Protein Family

Summary

Principal Investigator: Jennifer C Darnell
Abstract: DESCRIPTION (provided by applicant): Fragile X Syndrome (FXS) is caused by a triplet repeat expansion whose abnormal methylation silences expression of the Fragile X Mental Retardation protein, FMRP. Loss of function of this neuronal RNA- binding protein results in the intellectual disability, seizures and autistic features characteristic of FXS. FMRP is widely accepted to regulate translation of specific mRNAs and many forms of synaptic plasticity in neurons are dependent on its function. A missense mutation occurring in a Fragile X patient within an RNA binding domain of FMRP is sufficient to cause the disease and abolishes FMRP's polysome association, suggesting that identifying FMRP's mRNA targets and how FMRP regulates their translation is key to understanding the molecular basis for the cognitive and behavioral changes typical of the disease. A new technique designed to capture in vivo interactions of RNA binding proteins with their RNA targets, UV crosslinking- immunoprecipitation combined with high throughput sequencing (HITS-CLIP), was used to identify FMRP- interacting mRNAs in total brain polysomes including a mixture of many neuronal subtypes in different states of development or activity. FMRP was found to regulate mRNAs encoding both pre- and postsynaptic proteins important for synaptic function, suggesting that their mis-expression in the absence of FMRP might underlie defects in synaptic plasticity. This list of 842 FMRP targets is a resource for focusing research to ameliorate symptoms of FXS by inhibiting the activity of proteins that may be overexpressed in the absence of FMRP. To identify the subset of targets of FMRP that are most relevant for phenotypic defects this proposal aims to develop and apply an innovative approach to measuring cell-specific interactions of FMRP with RNA by engineering a new mouse (cTAG) which will conditionally tag FMRP from the endogenous locus in specific cells with temporal control by breeding with inducible Cre lines so that the tag can be used for HITS-CLIP. FXS arises due to loss of FMRP in the context of normal expression of its two family members, FXR1P and FXR2P, which share some functional redundancy with FMRP. This has led to the fundamental question of whether FXS arises due to loss of a function specific to FMRP and not shared by its paralogs, or whether FXS results from decreased dosage of a family of functionally redundant proteins. This proposal will test in vivo functional redundancy of the three paralogs with regard to RNA interactions, both globally and in specific neurons with FXR1/2P cTAG mice, and test whether increasing expression of FXR1/2P in the absence of FMRP can rescue phenotype. Successful accomplishment of the proposed Aims has significance for understanding the molecular basis of synaptic function as well as the human diseases that result from its dysfunction, including Fragile X Syndrome and autism. Identification of specific, phenotype-relevant mRNA targets of FMRP not shared by its paralogs will focus attention on inhibition of this subset while evidence for redundancy will spur attempts to therapeutically upregulate the levels of the FXR1/2P proteins in FXS.
Funding Period: 2001-04-15 - 2018-03-31
more information: NIH RePORT

Top Publications

  1. pmc Discrimination of common and unique RNA-binding activities among Fragile X mental retardation protein paralogs
    Jennifer C Darnell
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, NY 10065, USA
    Hum Mol Genet 18:3164-77. 2009
  2. pmc A mouse model of the human Fragile X syndrome I304N mutation
    Julie B Zang
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, New York, USA
    PLoS Genet 5:e1000758. 2009
  3. pmc Structure-function studies of FMRP RGG peptide recognition of an RNA duplex-quadruplex junction
    Anh Tuân Phan
    Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
    Nat Struct Mol Biol 18:796-804. 2011
  4. pmc Protein-RNA and protein-protein recognition by dual KH1/2 domains of the neuronal splicing factor Nova-1
    Marianna Teplova
    Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
    Structure 19:930-44. 2011
  5. pmc Defects in translational regulation contributing to human cognitive and behavioral disease
    J C Darnell
    Department of Molecular Neuro Oncology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
    Curr Opin Genet Dev 21:465-73. 2011
  6. pmc FMRP stalls ribosomal translocation on mRNAs linked to synaptic function and autism
    Jennifer C Darnell
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, NY 10065, USA
    Cell 146:247-61. 2011
  7. pmc The translation of translational control by FMRP: therapeutic targets for FXS
    Jennifer C Darnell
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, New York, USA
    Nat Neurosci 16:1530-6. 2013

Detail Information

Publications7

  1. pmc Discrimination of common and unique RNA-binding activities among Fragile X mental retardation protein paralogs
    Jennifer C Darnell
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, NY 10065, USA
    Hum Mol Genet 18:3164-77. 2009
    ..In contrast, FMRP is unique in its ability to recognize G-quadruplexes, suggesting the FMRP RGG domain may play a non-redundant role in the pathophysiology of the disease...
  2. pmc A mouse model of the human Fragile X syndrome I304N mutation
    Julie B Zang
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, New York, USA
    PLoS Genet 5:e1000758. 2009
    ..These data suggest that loss of FMRP function, particularly in KH2-mediated RNA binding and in synaptic plasticity, play critical roles in pathogenesis of the Fragile X Syndrome and establish a new model for studying the disorder...
  3. pmc Structure-function studies of FMRP RGG peptide recognition of an RNA duplex-quadruplex junction
    Anh Tuân Phan
    Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
    Nat Struct Mol Biol 18:796-804. 2011
    ..These findings on FMRP RGG domain recognition by a combination of G-quadruplex and surrounding RNA sequences have implications for the recognition of other genomic G-rich RNAs...
  4. pmc Protein-RNA and protein-protein recognition by dual KH1/2 domains of the neuronal splicing factor Nova-1
    Marianna Teplova
    Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
    Structure 19:930-44. 2011
    ....
  5. pmc Defects in translational regulation contributing to human cognitive and behavioral disease
    J C Darnell
    Department of Molecular Neuro Oncology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
    Curr Opin Genet Dev 21:465-73. 2011
    ..New approaches to the unbiased in vivo identification of maps of binding sites for these proteins on mRNA is expected to greatly increase our understanding of this crucial level of regulation in neuronal development and function...
  6. pmc FMRP stalls ribosomal translocation on mRNAs linked to synaptic function and autism
    Jennifer C Darnell
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, NY 10065, USA
    Cell 146:247-61. 2011
    ..In addition, they provide insight into the molecular basis of the cognitive and allied defects in FXS and ASD and suggest multiple targets for clinical intervention...
  7. pmc The translation of translational control by FMRP: therapeutic targets for FXS
    Jennifer C Darnell
    Laboratory of Molecular Neuro Oncology, The Rockefeller University, New York, New York, USA
    Nat Neurosci 16:1530-6. 2013
    ....

Research Grants30

  1. Mechanisms of Central Neuron Synaptogenesis
    ANN M CRAIG; Fiscal Year: 2013
    ....
  2. Center for Study of Opioid Receptors and Drugs of Abuse (CSORDA)
    Christopher J Evans; Fiscal Year: 2013
    ..Balleine, Bonci, Koob, Levitt, Nestler and Whybrow ex-officio, will provide programmatic oversight and coordinate training, outreach and a Pilot Program for the center. ..
  3. Genetic and Developmental Analyses of Fragile X Mental Retardation Protein
    Kendal Broadie; Fiscal Year: 2013
    ..My lab is the only lab poised to pursue this work, and I truly believe we can aid enormously in providing understanding and devising treatments for this most common heritable cause of cognitive dysfunction and autism spectrum disorder. ..
  4. Defining the messenger RNP code in the brain
    EUGENE WEI MING YEO; Fiscal Year: 2013
    ..Finally, we will leverage our computational expertise to build predictive models using this genome-wide, multi-scale, mRNP code in the brain. ..
  5. Deciphering the role of the RNA-binding protein, FXR1, in cardiac muscle assembly
    Carol C Gregorio; Fiscal Year: 2013
    ..Furthermore, the discovery of mRNA targets regulated by FXR1 during normal development and in diseased states may identify novel therapeutic approaches for heart disease. ..
  6. Function and Structure Adaptations in Forebrain Development
    PAT R LEVITT; Fiscal Year: 2013
    ..This project includes basic and clinical translational studies that will provide insight into gene- gene and gene-environment interactions that may underlie atypical brain functions in ASD. ..
  7. Mechanisms of Motor Skill Learning in the Fragile X Mouse Model
    Anna Dunaevsky; Fiscal Year: 2013
    ..This work is expected to provide important knowledge to develop therapies for FXS and other neurodevelopmental disorders such as autism, a mission of the NIH. ! ..
  8. Complex Persistant Pain Conditions: Unique &Shared Pathways of Vulnerability
    William Maixner; Fiscal Year: 2013
    ..Additionally, the proposed studies seek to characterize the biological pathways through which these genetic variations causally influence CPPCs. ..
  9. Homeostatic Regulation of Presynaptic Function by Dendritic mTORC1
    FREDRICK EARL HENRY; Fiscal Year: 2013
    ....
  10. Identifying therapeutic targets for autism using Shank3-deficient mice
    Joseph D Buxbaum; Fiscal Year: 2013
    ..In addition, these studies will advance our understanding of the basic neurobiology of the synapse and of brain components that underlie cognition and social behaviors. ..
  11. MULTIPLE ROLES OF FMRP IN SYNAPTIC FUNCTION AND PLASTICITY
    Vitaly A Klyachko; Fiscal Year: 2013
    ..We anticipate that these studies will provide fundamental new insights into the function of FMRP in synapses and a novel way to approach synaptic dysfunction in FXS. ..
  12. INVESTIGATION OF PROTOCADHERIN-10 IN MEF2- AND FMRP-MEDIATED SYNAPSE ELIMINATION
    Nien Pei Tsai; Fiscal Year: 2013
    ..The data from proposed experiments will provide molecular mechanism of MEF2- and FMRP-mediated synapse elimination as well as the function of an ASD gene in nervous system. ..
  13. Human Genome Sructural Variation
    Evan Eichler; Fiscal Year: 2013
    ..abstract_text> ..