Replication, repair, and reactivation.
In a recent issue of Current Biology, Kapoor et al. (2005) and Elmayan et al. (2005) illuminate the linkage between DNA replication and repair and transcriptional gene silencing in plants by showing that mutants in RPA2, a homolog of yeast and mammalian replication protein A, exhibit loss of silencing at transgene loci as well as some transposable elements. This is accompanied by a shift in histone H3 methylation modifications at these loci from a heterochromatic to a euchromatic pattern. Intriguingly, cytosine methylation is unaffected at the reactivated loci, indicating that transmission of DNA methylation and histone modification status can be uncoupled.
Vaughn
Matthew W
MW
Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA.
Tanurdzic
Milos
M
Martienssen
Rob
R
D000818:Animals; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D004260:DNA Repair / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D018744:DNA, Plant / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology; D017343:Genes, Plant / Q000502:physiology; D006801:Humans
D029681:Arabidopsis Proteins; D018744:DNA, Plant