RT-PCR analysis of the arsenite oxidase gene cluster. Lanes show the RT-PCR products from total RNA extracted from O. tritici SCII24. Lanes: 1, no amplification using primers (aoxRf and aoxAr) for intergenic region aoxR-aoxA; 2, successful amplification using primers (aoxAf and aox1Br) for intergenic region aoxA-aoxB; 3, successful amplification using primers (aoxB1f and cytCr) for intergenic region aoxB-cytC; 4, amplification of an inner region from the aoxB gene using the primers aox2Bf and aox2Br; 5, amplification of the cytC gene using the primers cytCf and cytCr. MW, molecular weight standards.