Neuroglobins from the zebrafish Danio rerio and the pufferfish Tetraodon nigroviridis

Neuroglobin is a recently discovered respiratory, porphyrin-containing prot ein that is expressed in the brain of mouse and man. Here we show that neur oglobin is also present in the teleost fish. Complete cDNA sequences are re ported from the pufferfish Tetraodon nigroviridis and the zebrafish Danio r erio. In addition, the neuroglobin gene of T. nigroviridis was sequenced, d emonstrating the conservation of the B12.2, E11.0 and G7.0 introns plus the presence of an additional intron in the 5' noncoding region. The fish neur oglobins each comprise 159 amino acids and are 84.3% identical. Phylogeneti c analyses show a basal position of the neuroglobins within the metazoan gl obin tree. An enhanced amino acid substitution rate was estimated for the f ish neuroglobins (similar to0.93 x 10(-9) amino acid substitutions per site and year) compared with their mammalian proteins (similar to0.39 x 10-9 re placements per site and year). (C) 2001 Academic Press.