Molecular characterization of a catalase null allele at the Cat3 locus in maize

Previous analysis has identified line IDS28 of maize (Zea mays L.) as being homozygous for a Catalase-3 (Cat3) null allele. Catalase-3 (CAT-3) protein-specific antibodies could not detect CAT-3 in extracts of several tissues of IDS28, which in a typical maize line possess CAT-3. The absence of CAT-3 resulted in a significant decrease in total catalase activity in those tissues where CAT-3 is the predominant catalase isozyme. RNA blot analysis indicated that IDS28 does not accumulate Cat3 transcript in any tissues. Genomic DNA blots revealed significant structural alterations in the Cat3 gene in IDS28. The results suggest that the molecular basis for Cat3 null phenotype in IDS28 may be a deletion in the 5' end of the Cat3 gene.