Fig. 6. GINS binding to TopBP1 is required for the origin firing step of replication.

a–c Heat map showing the intensity of chromatin-bound proteins recovered from TopBP1-depleted interphase Xenopus egg extracts supplemented wild type or mutant TopBP1 determined by quantitative mass spectrometry. Chromatin was isolated 75 min after sperm addition. All extracts contained 50 mg/ml aphidicolin and, where indicated, 2.25 mM geminin. The heat map shows log2 transformed label-free quantification (LFQ) intensities z-score normalized across rows and mean averaged over four independent replicates (n = 4). For the intensities of all proteins see Supplementary Data 2. b, c Volcano plots highlighting a selection of differentially detected proteins in samples described in (a). Log2 transformed LFQ intensities from four replicates each were analysed by a two-sided Student’s t-test. Significantly changed proteins with an Benjamini–Hochberg adjusted p-value of equal or less than 0.05 are reported in Supplementary Data 2. For clarity, only proteins involved in DNA replication are labelled (all significantly enriched proteins are labelled in Supplementary Fig. 14). d Experiment as in (a) was analysed by chromatin isolation and immunoblotting with the indicated antibodies. Coomassie staining of the gel part containing histones served as a loading control.