Fig. 7: POLD1 affects the transcriptional activity of MYC and is the target gene for transcriptional activation of MYC.

a Genome browser tracks of MYC or MYCN occupancy in the POLD1 loci in SKNSH, SKNAS or NB69 cells (public dataset: GSE138295⁵³). The genome browser map is displayed by IVG software. The brown region marks a region in the POLD1 promoter region where MYC is significantly enriched relative to input. b Effects of MYC depletion on POLD1 transcription levels in UM-UC-3 cells. c Schematic diagram of the two MYC binding sites in the POLD1 promoter region predicted by the JASPAR website. d Luciferase reporter assays of the POLD1 promoter in Vector, Flag-MYC, and WT POLD1 promoter or mutant POLD1 promoter (△Site 1 and △Site 2)-overexpressing 293T cells. e Luciferase reporter activities of the POLD1 promoter were assessed in the presence of exogenous MYC or POLD1 in POLD1-depleted 293T cells. f ChIP-qPCR assays of MYC binding to the POLD1, CDC45, CDK4, HNRNPU and PSMC4 promoters in 5637 cells with or without POLD1 depletion. CDC45, CDK4, HNRNPU and PSMC4 were both confirmed as MYC target genes and were shown to be significantly downregulated in 5637 cells with POLD1 knockdown in previous results. g ChIP-reChIP assays: The first round of ChIP analysis of binding of IgG or MYC to the promoter of target genes of MYC in 293T cells overexpressing GFP-POLD1, the second round of ChIP analysis of binding of GFP-POLD1 to the promoter target genes of MYC in the eluent for the first round of ChIP assay. h Schematic illustration of POLD1 and MYC binding as complexes to promoters of target genes of MYC to promote transcription. Statistical significance was determined by two-tailed Student’s T-test (b, d–g). Data shows mean ± SD, n = 3 biologically independent experiments in each group (b, d–g). TSS Transcription start site. Source data are provided as a Source Data file.