dCas9::nej(core) is an artificial transcriptional activator that contains a nuclease-dead form of the Streptococcus pyogenes Cas9 gene (contains the amino acid substitutions D10A and H840A) fused to a fragment corresponding to the catalytic core of the histone acetyltransferase encoded by the Drosophila melanogaster nej gene (this includes the bromodomain, RING domain, PHD domain and histone acetyltransferase domain). This driver can be used to overexpress a target gene of interest from its endogenous genomic locus, by combining it with a single guide RNA (sgRNA) that targets sequences upstream of the gene of interest's transcription start site. (FBrf0240018).