title: Neurotrophin-7: a novel member of the neurotrophin family from the zebrafish.
abstract: A novel member of the neurotrophin family, zebrafish neurotrophin-7 (zNT-7), was isolated from the zebrafish Danio rerio. The amino acid sequence of zNT-7 is more closely related to that of fish nerve growth factor (NGF) and neurotrophin-6 (NT-6) than to that of any other neurotrophin. zNT-7 is, however, equally related to fish NGF and NT-6 (65% and 63% amino acid sequence identity, respectively) indicating that it represents a distinct neurotrophin sequence. zNT-7 contains a 15 amino acid residue insertion in a beta-turn region in the middle of the mature protein. Recombinant zNT-7 was able to bind to the human p75 neurotrophin receptor and to induce tyrosine phosphorylation of the rat TrkA receptor tyrosine kinase, albeit less efficiently than rat NGF. zNT-7 did not interact with rat TrkB or TrkC, indicating a similar receptor specificity as NGF. We propose that a diversification of the NGF subfamily in the neurotrophin evolutionary tree occurred during the evolution of teleost fishes which resulted in the appearance of several additional members, such as zNT-7 and NT-6, structurally and functionally related to NGF.
authors.affiliation: Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
authors.forename: A S
authors.initials: AS
authors.lastname: Nilsson
authors.forename: M
authors.initials: M
authors.lastname: Fainzilber
authors.forename: P
authors.initials: P
authors.lastname: Falck
authors.forename: C F
authors.initials: CF
authors.lastname: Ibáñez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D017077:Culture Media, Conditioned; D006801:Humans; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D051381:Rats; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins
chemical_list: D017077:Culture Media, Conditioned; D009414:Nerve Growth Factors; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D011994:Recombinant Proteins; D029961:Zebrafish Proteins; C111574:ngfa protein, zebrafish