Figure 3.

Structural analysis of the EPA4/5 loci. Southern blot analysis was made to confirm the structure of EPA4 and EPA5. Genomic DNA was isolated from wild-type strain BG14 and cut with AgeI (AgeI recognizes a site in the unique region between the inverted repeats) and MfeI, and the bands were separated in an 0.8% agarose gel (see Materials and Methods). Probe #1 (pAP481) anneals 157 bp upstream from the ATG of both EPA4 and EPA5, giving 6.8-kb and 9.1-kb bands. Probe #2 (pAP479) anneals 1.343 kb from the telomere repeats, showing the expected 2.9-kb band. This Southern blot confirms the presence of EPA4/5 as an inverted repeat and that this subtelomeric region is reiterated in the genome.