The DNA Replication Program Is Altered at the FMR1 Locus in Fragile X Embryonic Stem Cells Academic Article uri icon

Overview

MeSH Major

  • DNA Replication
  • Embryonic Stem Cells
  • Fragile X Mental Retardation Protein
  • Fragile X Syndrome
  • Genetic Loci
  • Trinucleotide Repeats

abstract

  • Fragile X syndrome (FXS) is caused by a CGG repeat expansion in the FMR1 gene that appears to occur during oogenesis and during early embryogenesis. One model proposes that repeat instability depends on the replication fork direction through the repeats such that (CNG)n hairpin-like structures form, causing DNA polymerase to stall and slip. Examining DNA replication fork progression on single DNA molecules at the endogenous FMR1 locus revealed that replication forks stall at CGG repeats in human cells. Furthermore, replication profiles of FXS human embryonic stem cells (hESCs) compared to nonaffected hESCs showed that fork direction through the repeats is altered at the FMR1 locus in FXS hESCs, such that predominantly the CCG strand serves as the lagging-strand template. This is due to the absence of replication initiation that would typically occur upstream of FMR1, suggesting that altered replication origin usage combined with fork stalling promotes repeat instability during early embryonic development.

publication date

  • January 9, 2014

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed Central ID

  • PMC3920742

Digital Object Identifier (DOI)

  • 10.1016/j.molcel.2013.10.029

PubMed ID

  • 24289922

Additional Document Info

start page

  • 19

end page

  • 31

volume

  • 53

number

  • 1