FIG. 4.

Screening for auxotrophic mutants following transformation with ScURA3. (A) Sequence flanking the ScURA3 insertion was obtained by TAIL-PCR (KmLYS1) and was found to be highly homologous to that of K. lactis (KlLYS1). An arrow indicates the insertion site. (B) PCR amplification using genomic DNA from DMKU3-1042 (wild type [WT]) and the Lys⁻ mutant RAK3627 (LYS⁻) as templates confirmed the disruption of KmLYS1 by ScURA3. ScURA3 was inserted in an inverse direction relative to KmLYS1. The absence of a wild-type band in the lys1 disruptant suggests a haploid chromosomal constitution.