Figure 6.

 Transcription and recombination analysis of direct repeat systems carrying lacZ (3 kb) or PHO5 (1.5 kb) coding regions. A scheme of the deletion product formed by recombination between the direct repeats used is shown (A). The diagram of each direct repeat system indicates the 0.6-kb repeated sequences (shaded boxes), the orientation of the lacZ and PHO5 coding regions, the LEU2 promoter (Prm) and transcription terminators (Ter), and the transcripts driven from the LEU2 promoter (arrow), whose 3′ ends have been made to coincide with the position of the corresponding band in each gel (B). Total RNA was isolated from overnight cultures in synthetic media lacking tryptophan. The DNA probes used in the hybridization experiments were the 598-bp ClaI–EcoRV LEU2 repeat, and the 581-bp ClaI internal ACT1 fragment. The transcript corresponding to the LEU2 endogenous chromosomal band is indicated. No transcript initiates in the internal lacZ and PHO5 internal sequences as determined with specific lacZ and PHO5 DNA probes (data not shown).