dCas9::VP64b is an artificial transcriptional activator that contains a nuclease-dead form of the Streptococcus pyogenes Cas9 gene (contains the mutations D10A, H839A, H840A and N863A) fused to the VP64 activation 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 (FBrf0240569).