Fig. 4.

Heterochromatin enrichment on CDK12 knockdown impairs neuronal gene activation. (A) Heat map shows that the affected X-chromosome genes are highly expressed in the brain of WT Drosophila; 52 X-chromosome genes with increased HP1 binding after CDK12 depletion are selected. Expression data were obtained from the FlyAtlas database (18). The relative expression levels were determined using a log₁₀ scale and normalized to the whole-fly genome-wide average. (B) The neuronal genes are highly activated in the adult brain. The relative expression levels of neuronal genes in the third-instar larval brain and the adult brain in WT were monitored by qRT-PCR and normalized to rp49 mRNA; mnb showed no association with HP1 or H3K9me2 in our ChIP-seq analysis and served as a negative control. Error bars indicate SD (n = 3). (C and D) The depletion of CDK12 reduced the transcription of neuronal genes, whereas introducing Su(var)205⁰⁵ restored the expression level. The relative expression levels of neuronal genes in the adult brain after (C) CDK12 depletion or CDK12 depletion heterozygous for Su(var)205⁰⁵ or (D) CycK depletion were monitored by qRT-PCR as described in B. Significance was analyzed by ordinary one-way ANOVA in GraphPad Prism. Error bars indicate SD (n = 3). CON, control; n.s., not significant. *P < 0.05; **P < 0.01.