Identification of the core protein carrying the Tn antigen in mouse brain: specific expression on syndecan-3.
We isolated glycoproteins carrying the Tn antigen, which was expressed spatiotemporally in the developing mouse brain. The Tn antigen was expressed on two molecular species with a molecular weight from 200 to 350 kDa and 110 to 160 kDa, as judged on SDS-PAGE. Although the two glycoproteins showed different susceptibilities to heparitinase I and solubilities in a salt solution, after treatment with V8 protease they showed the same mobility corresponding to a molecular weight of 90 kDa on SDS-PAGE, suggesting that these two molecules shared a common core protein. Partial N-terminal sequences of the glycoproteins were determined, i.e. AQRXRNENFERPV and ALAAPXAPAMLP, which were identified as the sequences of the N-terminal and central portions of syndecan-3, respectively. Both glycoproteins were reactive to anti-mouse syndecan-3 antibody. These results suggest that one is a soluble syndecan-3 cleaved between mucin-like domain and transmembrane domain, and the other is a membrane-bound syndecan-3 lacking N-terminal glycosaminoglycan attachment sites, and that both glycoproteins have a mucin-like domain characteristic of syndecan-3, in which the Tn antigen may be expressed.
Akita
K
K
Department of Biotechnology, Faculty of Engineering, Kyoto Sangyo University, Japan.
Fushiki
S
S
Fujimoto
T
T
Munesue
S
S
Inoue
M
M
Oguri
K
K
Okayama
M
M
Yamashina
I
I
Nakada
H
H
D000595:Amino Acid Sequence; D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry* / Q000302:isolation & purification; D001665:Binding Sites; D001921:Brain / Q000196:embryology; D001923:Brain Chemistry; D002241:Carbohydrates / Q000737:chemistry / Q000302:isolation & purification; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification; D008562:Membrane Glycoproteins / Q000737:chemistry*; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D009077:Mucins / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000737:chemistry*; D053670:Syndecan-3
D015295:Antigens, Tumor-Associated, Carbohydrate; D002241:Carbohydrates; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D009077:Mucins; D011509:Proteoglycans; C508302:Sdc3 protein, mouse; D053670:Syndecan-3; C040286:Tn antigen