a, Whole mounts of D1−/− retinas infected with viruses encoding activated Notch and β-galactosidase (NIN-NICD, see ) or with vectors encoding only β-galactosidase (NIN), stained with X-gal to visualize clones of infected cells (arrowheads). b, higher magnifications of a. c, percentage of β-galactosidase-positive clones composed of 1, 2, 3 and ≥4 cells. d, Cyclin D1 was immunoprecipitated from P0 retinas and probed with indicated antibodies. e, Targeted ChIP on P0 retinas using anti-FLAG (to bring down cyclin D1) or with anti-CBP antibodies, followed by real-time PCR with Notch1-specific primers. Lower panel: ChIP with anti-FLAG followed by re-ChIP with anti-CBP antibodies and real-time PCR. f, Cyclin D1 was knocked-down (+shCycD1) or overexpressed (+CycD1) in R28 cells. ChIP with anti-cyclin D1, anti-CBP, anti-acetylated histone H4K5 (AcH4K5) or anti-acetylated histone H3K9,14 (AcH3K9,14) antibodies was followed by real-time PCR with Notch1-specific primers. The results show fold-difference compared to cells transduced with empty vectors. g, ChIP using anti-CBP and anti-AcH4K5 antibodies followed by real-time PCR with Notch1-specific primers using wild-type and D1−/− retinas. Error bars, SD.