Debranching Enzyme Homolog 1 (DBR1)

The RNA lariat debranching enzyme, or DBR1, specifically hydrolyzes 2-prime-to-5-prime branched phosphodiester bonds at the branch point of excised lariat intron RNA and converts them into linear molecules.The deduced 545-amino acid protein is approximately 42% identical to the fission yeast, budding yeast, and worm enzymes, and is 79% identical to the mouse enzyme. It contains a conserved N terminus, especially within the first 200 residues. Immunoblot analysis showed expression of a 62-kD protein with debranching activity. EST database searching suggested that DBR1 is of extremely low abundance, may be enriched in certain tissues, and has high specific enzymatic activity. Complementation analysis indicated that DBR1 is functional in yeast.