Figure 1 .

Isolation of an endos null allele. (A) The endos^215-4 allele generated by imprecise excision of EY4709 (triangle). Thick bars represent exons (coding region in black) and black lines represent introns. The neighboring gene CG6650 encodes two mRNA isoforms and one coding region; only RA–CG6650 overlaps with endos, as shown here. The gap indicates the deleted region in endos^215-4. (B) RT–PCR analysis showing reduced levels of endos mRNA in endos^215-4 homozygous third-instar larvae. Rp49 is the control transcript. endos^215-4/TM3 are heterozygous controls. The negative control (—) is RT–PCR without a template. (C) Western blot showing that Endos protein is completely lacking in endos^215-4 homozygous larvae. Actin was used as a loading control. (D) RT–PCR analysis showing that expression of CG6650 is unaffected in endos^215-4 homozygous mutants. Controls are as in B. Right: RT–PCR using 1:10 dilutions of RT reactions.