TY - JOUR
T1 - An origin of DNA replication in the promoter region of the human fragile X mental retardation (FMR1) gene
AU - Gray, Steven J.
AU - Gerhardt, Jeannine
AU - Doerfler, Walter
AU - Small, Lawrence E.
AU - Fanning, Ellen
PY - 2007/1
Y1 - 2007/1
N2 - Fragile X syndrome, the most common form of inherited mental retardation in males, arises when the normally stable 5 to 50 CGG repeats in the 5′ untranslated region of the fragile X mental retardation protein 1 (FMR1) gene expand to over 200, leading to DNA methylation and silencing of the FMR1 promoter. Although the events that trigger local CGG expansion remain unknown, the stability of trinucleotide repeat tracts is affected by their position relative to an origin of DNA replication in model systems. Origins of DNA replication in the FMR1 locus have not yet been described. Here, we report an origin of replication adjacent to the FMR1 promoter and CGG repeats that was identified by scanning a 35-kb region. Prereplication proteins Orc3p and Mcm4p bind to chromatin in the FMR1 initiation region in vivo. The position of the FMR1 origin relative to the CGG repeats is consistent with a role in repeat maintenance. The FMR1 origin is active in transformed cell lines, fibroblasts from healthy individuals, fibroblasts from patients with fragile X syndrome, and fetal cells as early as 8 weeks old. The potential role of the FMR1 origin in CGG tract instability is discussed.
AB - Fragile X syndrome, the most common form of inherited mental retardation in males, arises when the normally stable 5 to 50 CGG repeats in the 5′ untranslated region of the fragile X mental retardation protein 1 (FMR1) gene expand to over 200, leading to DNA methylation and silencing of the FMR1 promoter. Although the events that trigger local CGG expansion remain unknown, the stability of trinucleotide repeat tracts is affected by their position relative to an origin of DNA replication in model systems. Origins of DNA replication in the FMR1 locus have not yet been described. Here, we report an origin of replication adjacent to the FMR1 promoter and CGG repeats that was identified by scanning a 35-kb region. Prereplication proteins Orc3p and Mcm4p bind to chromatin in the FMR1 initiation region in vivo. The position of the FMR1 origin relative to the CGG repeats is consistent with a role in repeat maintenance. The FMR1 origin is active in transformed cell lines, fibroblasts from healthy individuals, fibroblasts from patients with fragile X syndrome, and fetal cells as early as 8 weeks old. The potential role of the FMR1 origin in CGG tract instability is discussed.
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U2 - 10.1128/MCB.01382-06
DO - 10.1128/MCB.01382-06
M3 - Article
C2 - 17101793
AN - SCOPUS:33846123946
SN - 0270-7306
VL - 27
SP - 426
EP - 437
JO - Molecular and cellular biology
JF - Molecular and cellular biology
IS - 2
ER -