Lippincott Williams & Wilkins, Inc., Philadelphia
Molecular Cloning of Testican-2
Defining a Novel Calcium-Binding Proteoglycan Family Expressed in Brain
Article first published online: 18 JAN 2002
Journal of Neurochemistry
Volume 73, Issue 1, pages 12–20, July 1999
How to Cite
Vannahme, C., Schübel, S., Herud, M., Gösling, S., Hülsmann, H., Paulsson, M., Hartmann, U. and Maurer, P. (1999), Molecular Cloning of Testican-2. Journal of Neurochemistry, 73: 12–20. doi: 10.1046/j.1471-4159.1999.0730012.x
Abbreviations used: CD, circular dichroism; DIG, digoxigenin; EC domain, extracellular Ca2+-binding domain; EST, expressed sequence tag; FS domain, follistatin-like domain; ORF, open reading frame; SDS, sodium dodecyl sulfate; SPARC, secreted protein, acidic and rich in cysteine; SSC, saline-sodium citrate; TY domain, thyroglobulin-like domain; UTR, untranslated region.
- Issue published online: 18 JAN 2002
- Article first published online: 18 JAN 2002
- Modular protein;
- Central nervous system
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.