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. Author manuscript; available in PMC: 2011 Oct 11.
Published in final edited form as: Methods Mol Biol. 2008;475:299–314. doi: 10.1007/978-1-59745-250-2_17

Figure 1. Experimental strategy to obtain gene expression signatures of purified Drosophila embryonic mesodermal cells.

Figure 1

(A) Transgenic, stage 11, Drosophila embryo expressing Gal4 under the control of the twi promoter and GFP under the UAS regulatory sequence (21), resulting in GFP-positive mesodermal cells. (B) Transgenic, stage 11, wingless (wg) mutant embryo with GFP-positive mesodermal cells. (C) Genetic crossing scheme to obtain homozygous mutant GFP-positive mesodermal cells. Strains bearing independently generated recombinant chromosomes having the mutant gene of interest (for example, wg) and either the twiGal4 or UASGFP transgenes are crossed. (D) A representative fluorescence-activated cell sorting (FACS) experiment to obtain total RNA from mesodermally purified cells. (E) Representative FACS scatter plots before (top panel) and after (bottom panel) the separation of GFP-positive and -negative cell populations. Top panel, upper box: GFP-positive sort in blue; top pannel, lower box: GFP-negative sort in green. Bottom panel, upper box: in blue are shown the re-sorted GFP-positive cells to verify that purity obtained from the primary sort was greater than 90%.