Molecular cloning and characterization of NEU4, the fourth member of the human sialidase gene family

• Published in: Genomics (San Diego, Calif.) Vol. 83; no. 3; pp. 445 - 453
• Main Authors: Monti, E, Bassi, M.T, Bresciani, R, Civini, S, Croci, G.L, Papini, N, Riboni, M, Zanchetti, G, Ballabio, A, Preti, A, Tettamanti, G, Venerando, B, Borsani, G
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-03-2004; Elsevier
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Cloning, Molecular; COS Cells; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Gene expression profile; Gene structure; Genes. Genome; Genetic Vectors; Genetics of eukaryotes. Biological and molecular evolution; Human sialidase; Humans; Mice; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Neuraminidase - genetics; Neuraminidase - metabolism; Plasmids; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Subcellular localization; Transfection; Transient transfection; Transient transfection; Human sialidase; Gene structure; Subcellular localization; Gene expression profile; Human; Enzyme; Genomics; EC 3.2.1.18; Gene expression; Structure gene; Transients; Characterization; Transfection; Glycosidases; Exo-α-sialidase; Hydrolases; Multigene family; Molecular cloning; Localization; O-Glycosidases
• ISSN: 0888-7543; 1089-8646
• DOI: 10.1016/j.ygeno.2003.08.019

Several mammalian sialidases have been cloned so far and here we describe the identification and expression of a new member of the human sialidase gene family. The
NEU4 gene, identified by searching sequence databases for entries showing homologies to the human cytosolic sialidase NEU2, maps in 2q37 and encodes a 484-residue protein. The polypeptide contains all the typical sialidase amino acid motifs and, apart from an amino acid stretch that appears unique among mammalian sialidases, shows a high degree of homology for NEU2 and the plasma membrane-associated (NEU3) sialidases. RNA dot-blot analysis showed a low but wide expression pattern, with the highest level in liver. Transient transfection in COS7 cells allowed the detection of a sialidase activity toward the artificial substrate 4MU-NeuAc in the acidic range of pH. Immunofluorescence staining and Western blot analysis demonstrated the association of NEU4 with the inner cell membranes.