Kvon, E.Z. et al. Nature doi:10.1038/nature13395 (1 June 2014).

Gene expression patterns during organismal development are controlled by regulatory sequences in the genome known as enhancers. In recent work, Kvon et al. describe a genome-wide study of enhancer activity during fruit fly embryogenesis. They assessed gene expression patterns in developing fly embryos by applying high-throughput in situ hybridization to a collection of transgenic fly lines, each bearing a GAL4 transcriptional reporter under the control of an enhancer candidate (a 2-kilobase fragment of genomic DNA). The collection covers 13–14% of the noncoding and nonrepetitive genome. Almost half the candidate enhancers are active in the embryo, the authors report, and a substantial percentage of them regulate distal genes. The resulting collection of annotated expression patterns and computationally identified cis-regulatory motifs are available to other researchers.