Figure 2

RECQ1 is recruited to common fragile site FRA3B after treatment with aphidicolin. A. Genomic organization of the FRA3B region. Primer sets used for qPCR analyses of distal (FDR) and central (FCR) region within the FRA3B locus are indicated. B. Quantification of cross-linked FRA3B chromatin immunoprecipitated from HeLa cells using the indicated antibodies. HeLa cells were either untreated or treated with aphidicolin (0.5 μM) for 24 h and then processed for ChIP using a RECQ1-specific antibody. Phosphorylated H2AX (γH2AX) antibody was used as a positive control for FRA3B enrichment, and rabbit IgG served as negative control in ChIP experiments. qPCR was performed with two different sets of primers specific for the central and distal regions within FRA3B locus. Fold enrichment over IgG was determined and is shown for each primer pair for the ChIP. Results are expressed as means ± SEM for at least three independent experiments. C. A representative gel of the amplified DNA immunoprecipitated with indicated antibodies. Input represents 1% of the cross-linked chromatin used for ChIP. D . Binding of RECQ1 to FRA3B after treatment with hydroxyurea. Quantification of cross-linked FRA3B chromatin immunoprecipitated from HeLa cells using the indicated antibodies. HeLa cells were either untreated or treated with hydroxyurea (2 mM) for 24 h and processed for ChIP using a RECQ1-specific antibody. γH2AX antibody was used as a positive control for FRA3B enrichment, and rabbit IgG served as negative control in ChIP experiments. qPCR was performed with two different sets of primers specific for the central and distal regions within FRA3B locus. Fold enrichment over IgG was determined and is shown for each primer pair for the ChIP. Results are expressed as means ± SEM for at least three independent experiments. APH, aphidicolin; HU, hydroxyurea.