Clusters of Drosophila housekeeping genes and experimental design. (A) Housekeeping genes (HK) are represented as purple boxes and regulated genes (REG) as gray boxes. The vertical bars on top represent the average expression of each gene across 30 conditions. Housekeeping genes form densely packed clusters interspersed by regulated genes. (B) Reporter libraries are generated by barcoding-PCR, introducing a random barcode. Upon co-electroporation with a Sleeping Beauty expression plasmid in Kc167 cells, barcoded reporters are integrated at random in the Drosophila genome. (C) Barcoded reporters are mapped by inverse PCR. Quantification of expression is performed by RT-PCR on the barcode and normalization for the copy number of each insertion by PCR with the same primers.
