title: Molecular cloning of testican-2: defining a novel calcium-binding proteoglycan family expressed in brain.
abstract: We have screened a human cDNA library using an expressed sequence tag related to the BM-40/secreted protein, acidic and rich in cysteine (SPARC)/osteonectin family of proteins and isolated a novel cDNA. It encodes a protein precursor of 424 amino acids that consists of a signal peptide, a follistatin-like domain, a Ca2+-binding domain, a thyroglobulin-like domain, and a C-terminal region with two putative glycosaminoglycan attachment sites. The protein is homologous to testican-1 and was termed testican-2. Testican-1 is a proteoglycan originally isolated from human seminal plasma that is also expressed in brain. Northern blot hybridization of testican-2 showed a 6.1-kb mRNA expressed mainly in CNS but also found in lung and testis. A widespread expression in multiple neuronal cell types in olfactory bulb, cerebral cortex, thalamus, hippocampus, cerebellum, and medulla was detected by in situ hybridization. A recombinant fragment consisting of the Ca2+-binding EF-hand domain and the thyroglobulin-like domain of testican-2 showed a reversible Ca2+-dependent conformational change in circular dichroism studies. Testican-1 and -2 form a novel Ca2+-binding proteoglycan family built of modular domains with the potential to participate in diverse steps of neurogenesis.
authors.affiliation: Institute for Biochemistry II, Medical Faculty, University of Cologne, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Vannahme
authors.forename: S
authors.initials: S
authors.lastname: Schübel
authors.forename: M
authors.initials: M
authors.lastname: Herud
authors.forename: S
authors.initials: S
authors.lastname: Gösling
authors.forename: H
authors.initials: H
authors.lastname: Hülsmann
authors.forename: M
authors.initials: M
authors.lastname: Paulsson
authors.forename: U
authors.initials: U
authors.lastname: Hartmann
authors.forename: P
authors.initials: P
authors.lastname: Maurer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002118:Calcium / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D005333:Fetus; D006801:Humans; D017403:In Situ Hybridization; D008168:Lung / Q000737:chemistry; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011509:Proteoglycans / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D013735:Testicular Hormones / Q000235:genetics; D013737:Testis / Q000737:chemistry; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D011509:Proteoglycans; D012333:RNA, Messenger; C504369:SPOCK1 protein, human; C504404:SPOCK2 protein, human; C504370:Spock1 protein, mouse; C504405:Spock2 protein, mouse; D013735:Testicular Hormones; D002118:Calcium