ABSTRACT: Purpose: In Drosophila, we tried to determine the neural activity-dependent transcription controlled by Kdm4B. We conducted nuclear RNA-seq analysis in mushroom body in Drosophila, either in naive state or after optogenetic activation. Methods: The nuclei of mushroom body were collected by immunoprecipitation-based method (Hirano Y., et al, 2016, Nature Communications, also see extraction protocol below). mRNA was purified from the mushroom body nuclei with oligo dT magnetic beads, and used to prepare library. After deep sequencing in triplicate using illumine Hiseq X, the adaptors were trimmed via Trimommatic, followed by mapping to the Drosophila reference genome, dm6 from UCSC using STAR. The reads with low mapping quality below 8 and the non-primary mapped reads were eliminated. The filtered reads were analyzed with HTSeq-count to obtain numbers of the reads mapped on exons, which was further analyzed on R using DESeq2 Results: Using an optimized data analysis workflow, we mapped about 9-18 million reads for ChIP-seq, and 30-40 million reads for nuclear RNA-seq to Drosophila reference genome, dm6 In ChIP-seq, binding of all proteins was enriched nearby the transcriptional start site (TSS). The binding sites determined were 1,237 for CoRest-C, 2,717 for Rpd3, and 6,684 for CBP. Importantly, among CoRest-C binding sites, overlapping sites of CoRest-C and CBP were 1,038/1,237 (83.9%), those of CoRest-C and Rpd3 were 789/1,237 (63.8%), and those of CoRest-C, Rpd3, and CBP were 704/1,237 (56.9%), suggesting that these three proteins colocalize on the specific genomic regions In nuclear RNA-seq, we found that upregulation of gene expression is robust at 10-min after 5-min optogenetic activation. The genes showing significant difference were 2,702 at this time point, in which 1,582 genes showed increase, and the rest showed decrease in the expression. Among the 1,582 increased genes, 1,055 genes were bound by CBP, supporting the idea that CBP is an important factor in activity-dependent transcription. Furthermore, 338 was bound by CoRest-C, 254 of which showed colocalization with CBP and Rpd3. Conclusions: Our study represents activity-dependent transcription in mushroom body in Drosophila, which is mediated by Kdm4B.
