Structure and regulated expression of genes encoding fructose biphosphate aldolase in Trypanosoma brucei

Low stringency hybridisation with a rabbit aldolase cDNA was used to select cDNA clones encoding fructose biphosphate aldolase in Trypanosoma brucei. A clone which is almost full length encodes a protein of 41 027 daltons which has 50% identity with rabbit aldolase A and slightly lower homology with B-type aldolases. The homologous mRNA is at least 6-fold more abundant in bloodstream trypomastigotes than in procyclic forms, as expected from measurements of enzyme activity. Genomic mapping results indicate that trypanosomes have four copies of the aldolase gene arranged as two copies of a tandem repeat. The protein has a short N-terminal extension (relative to other known aldolases) which could be involved in the glycosomal localisation of the enzyme.