Expression of a novel human sialidase encoded by the NEU2 gene

Sialidases (EC 3.2.1.18) are a group of glycohydrolytic enzymes, widely distributed in nature, that cleave sialic acid residues from the oligosaccharide components of glycoconjugates. All of the sialidase enzymes thus far characterized share an Asp block, repeated three to five times in the primary structure, and an F/YRIP sequence motif that is part of the active site. Using a sequence homology-based approach, we have identified a novel human gene, named NEU2, mapping to chromosome 2q37. The nucleotide sequence analysis of the gene has shown that it contains only one intron of about 1.25 kb, and the longest open reading frame encodes a protein of 380 amino acids, with a two-Asp block consensus, and the YRIP sequence. In the putative promoter sequence there are a classical TATAA box and four E boxes, which are consensus binding sites for muscle-specific transcription factors. Northern blot analysis revealed expression of the NEU2 transcript only in skeletal muscle.