FIG. 1.

Stability of the mutation after long-term culture. PCR to discard contamination or instability of the gene-targeted mutation directed towards the LYT1 gene. The bar represents the gene, with its initiation and termination codons (black dots), and the approximate location and orientation of primers. The reaction was performed using genomic DNA isolated from either the L16 clone (LYT1 null mutant) or the WT CL Brenner strain as the template. Three sets of primers were used. The absence of amplification products on the L16 clone demonstrated that both alleles of LYT1 were completely replaced. M, DNA size marker.