Figure 2.

Genomic organization of the gdt1 gene. REMI 2-9 was the original REMI mutant generated by insertion of the DIV-2 vector into the BamHI site of the gdt1 gene (192 bp after the ATG start condon). The right flank of 3.7 kb was isolated by plasmid rescue. The L8 strain was generated by homologous recombination with the 3.7-kb fragment containing the Bs^R cassette inserted into the XbaI site. The K series mutants were generated by insertion of a vector containing the 3.7-kb fragment, the Bs^R cassette, and pGem7Z into the HindIII site. The X series mutants were generated by homologous recombination with the 3.7-kb fragment containing the Bs^R cassette and plasmid Psp72 inserted into the XbaI site. In the D series mutants, a 2.6-kb deletion was introduced by replacing the internal XbaI–EcoRI fragment within the 3.7-kb fragment with a pGem3 vector containing the Bs^R cassette. The 5′ end of gdt1 was isolated by plasmid rescue from an X series mutant. The 3′ end was isolated from a D series mutant and confirmed by a cDNA clone and inverse PCR.