title: Reactivation of FMR1 by CRISPR/Cas9-Mediated Deletion of the Expanded CGG-Repeat of the Fragile X Chromosome.
abstract: Fragile X syndrome (FXS) is a common cause of intellectual disability that is most often due to a CGG-repeat expansion mutation in the FMR1 gene that triggers epigenetic gene silencing. Epigenetic modifying drugs can only transiently and modestly induce FMR1 reactivation in the presence of the elongated CGG repeat. As a proof-of-principle, we excised the expanded CGG-repeat in both somatic cell hybrids containing the human fragile X chromosome and human FXS iPS cells using the CRISPR/Cas9 genome editing. We observed transcriptional reactivation in approximately 67% of the CRISPR cut hybrid colonies and in 20% of isolated human FXS iPSC colonies. The reactivated cells produced FMRP and exhibited a decline in DNA methylation at the FMR1 locus. These data demonstrate the excision of the expanded CGG-repeat from the fragile X chromosome can result in FMR1 reactivation.
authors: Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors: Nina
authors: N
authors: Xie
authors: Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors: He
authors: H
authors: Gong
authors: Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors: Joshua A
authors: JA
authors: Suhl
authors: Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors: Pankaj
authors: P
authors: Chopra
authors: Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors: Tao
authors: T
authors: Wang
authors: Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America.|Departments of Biochemistry and Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors: Stephen T
authors: http://orcid.org/0000-0001-7748-4750
authors: ST
authors: Warren
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D019175:DNA Methylation; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics*; D005600:Fragile X Syndrome / Q000235:genetics*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D018911:Trinucleotide Repeats
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1