Molecular cloning of testican-2: defining a novel calcium-binding proteoglycan family expressed in brain.
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.
Vannahme
C
C
Institute for Biochemistry II, Medical Faculty, University of Cologne, Germany.
Schübel
S
S
Herud
M
M
Gösling
S
S
Hülsmann
H
H
Paulsson
M
M
Hartmann
U
U
Maurer
P
P
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
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