Figure 2. Gene locus organization and generation of dilp mutants.

(A–C) Null mutations for dilp1, 2, 3, 4, 5, 7, 2–3, and 1–4 were generated by ends-out homologous recombination and by imprecise P-element excision for dilp6 (D). (A) The dilp1–4 genes cluster at cytological position 67C8 is separated from dilp5 by two intervening genes of unknown function (Flybase: CG32052 and CG33205). (B) dilp5 is located within an intron of the CG33205 gene. (C) dilp7 is located on the X-chromosome at 3E2 immediately downstream of the essential Poly(ADP-ribose) glycohydrolase (Parg) gene. Donor constructs (dilp ko) for ends-out homologous recombination are indicated by grey bars. Gap between grey bars indicates the genomic region replaced by a white^hs marker gene. Coding parts of exons are marked in black, non-coding parts by white boxes. (D) Transposon integration line KG004972 was used to generate dilp6 deletion mutants dilp6⁴¹ and dilp6⁶⁸. Note: both dilp6 deletion alleles contain remaining P-element sequence, hatched line: region of breakpoint in dilp6⁴¹. (E) PCR on genomic DNA of dilp mutants with dilp specific primer combinations shows homologous recombination mediated replacement of dilp genes by the white^hs marker gene and deletion of dilp6 in dilp6⁶⁸ mutants (M: mutant, C: control). (F) RT–PCR analysis confirms that dilp mutants are transcript null alleles. dilp6⁴¹ mutants express ectopic dilp6 transcripts that lack the first exon but contain the full ORF. dilp6⁶⁸ mutants are dilp6 transcript null alleles.