A late origin of DNA replication in the trinucleotide repeat region of the human FMR2 gene.
We confirmed that the replication of the fragile-X E site (FRAXE) in human chromosomal band Xq28 occurs at six hours into the eight-hour S phase of normal human fibroblasts. In this late-replicating region, we mapped an origin of DNA replication within the promoter of FMR2. This origin is coincident with CpG islands, the trinucleotide repeat, and exon 1 of the FMR2 gene. Identification of this origin may aid in the investigation of the mechanism of trinucleotide repeat expansion and its effect on FMR2 expression. In addition, knowledge of the chromosomal locations and sequence characteristics of both early and late origins of DNA replication, such as the one described in this report, will facilitate studies of the molecular determinants of the time of activation of different origins of replication and allow us to refine our insights concerning origin inactivation in response to the DNA damage-induced intra-S checkpoint.
Chastain
Paul D
PD
Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7525, USA.
Cohen
Stephanie M
SM
Brylawski
Bruna P
BP
Cordeiro-Stone
Marila
M
Kaufman
David G
DG
D002460:Cell Line; D041321:Chromosomes, Human, X; D018899:CpG Islands; D004249:DNA Damage; D004261:DNA Replication; D005091:Exons; D005600:Fragile X Syndrome / Q000235:genetics; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D018741:Replication Origin; D016196:S Phase; D015534:Trans-Activators / Q000235:genetics*; D019680:Trinucleotide Repeat Expansion; D018911:Trinucleotide Repeats
C099930:AFF2 protein, human; D009687:Nuclear Proteins; D015534:Trans-Activators