Sequence analysis of this 3547 bp fragment resulted in the identification of an open reading frame containing a portion of the ATP6 gene fused with a part of the 26s ribosomal RNA gene. Analysis of gene expression in mitochondria of restored vs sterile cms 'T' mitochondria revealed that novel transcripts were produced in sterile individuals. CMS T produces a recombinationally-generated recombinant product that the restorer genes suppress. This product results in mitochondria that are fragile to the stresses which occur during pollen production, and which acts as a channel for B. maydis toxin entry. T' cytoplasm has an extra large duplication, and produces a subset of circular molecules which are of unique size.
Restorers reduce the level of expression of the inappropriate, chimeric gene products.
Some evidence suggests that this is a primary way by which this nuclear-mitochondrial interaction operates. Recognizing that these mitochondria have to work properly in the species from which they derive, one might think that their nuclei carry genes which restore their species-specific defects. This has turned out to be generally true. Sally Mackenzie mapped a group of independently identified Rf genes in Phaseolus . These genes map to the same location.