Fig. 3
Tissue-specific P-TEFb recruitment is associated with the release of paused Pol II into productive elongation at DV promoters. a Schematic of P-TEFb (composed of CycT and CDK9 subunits) mediated release of promoter-proximal paused Pol II into productive elongation. P-TEFb phosphorylates serine 2 of the Pol II carboxyl-terminal domain (CTD) to stimulate elongation. BRD4/fs(1)h binds to acetylated histones and helps recruit P-TEFb. b The fold change (log2) in CycT, Cdk9, and BRD4/fs(1)h CUT&Tag tissue-specific enrichment scores from Toll mutant embryos at DV promoters and enhancers. Significant differences in enrichment are from the Wilcoxon signed-rank test and indicated by asterisks, * = P < 0.05, ** = P < 0.01, *** = P < 0.001. c Genome browser shots of Toll mutant CycT, Cdk9 and BRD4/fs(1)h CUT&Tag, and H3K27ac ChIP-seq at dpp, ind, and twi and d Toll mutant PRO-seq, CBP ChIP-seq, and CycT and BRD4/fs(1)h CUT&Tag at the Doc locus. The position of the Doc E1 enhancer deletion [7] is denoted. e ChIP-qPCR enrichment of CycT and BRD4/fs(1)h at the Doc1-3 promoters and the intact E4 enhancer in Doc enh delΔ/Δ embryos (2–4 h AEL) relative to enh+/+ embryos (n = 3–4). Error bars show SEM. Significant differences in occupancy (two tailed, unpaired t-test) are indicated by asterisks (* = P < 0.05). f RT-qPCR quantification of CycT, Cdk9 and DV-regulated genes (dpp, zen, ind, sog, twi, and sna) mRNA levels (relative to 28S rRNA) in wild-type embryos and P-TEFb maternally overexpressed (OE) embryos. Error bars show SEM. Significant differences in mRNA (two tailed, unpaired t-test) are indicated by asterisks (* = P < 0.05, ** = P < 0.01, *** = P < 0.001). g (top) Images of whole-mount in situ hybridization in wild-type and P-TEFb OE mutant embryos (2–4 h AEL) with probes hybridized to mRNAs of the DV-regulated genes in f and (bottom) quantification of the proportion of embryos with ectopic signal for each probe. The number of embryos sampled is detailed in the methods