(A) Northern blot analysis of total RNA isolated from different individual primary transformants. PR1-IRMOM, empty vector (EV) and 35S-IRMOM transgenics were treated with (+) or without (−) BTH as described in Methods. mom mutant (without GUS locus; Amedeo et al., 2000) RNA was used as a control (last lane). The same blot was probed with TSI, GUS and cDNA of constitutively expressed RAN gene (Ras related nuclear protein; Haizel et al., 1997) as a loading control. (B) RT–PCR detection of MOM1 transcript. Total RNA isolated from individual primary transformants was reverse transcribed and PCR amplified with MOM1 specific primers and Act2 (Actin2) primers as described in Methods. M, marker; wt, wild type.