HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kobayashi, K. Articles by Simmer, J.P. Search for Related Content PubMed PubMed Citation Articles by Kobayashi, K. Articles by Simmer, J.P.

Splicing Determines the Glycosylation State of Ameloblastin

¹ Department of Biologic and Materials Sciences, Dental Research Lab, 1210 Eisenhower Place, Ann Arbor, MI 48108, and
² Department of Orthodontics and Pediatric Dentistry, University of Michigan School of Dentistry, 1011 N. University, Ann Arbor, MI 48109-1078, USA; and
³ Department of Periodontics and Endodontics and
⁴ Department of Biochemistry, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan

^* corresponding author, jsimmer{at}umich.edu

In developing porcine enamel, the space between enamel rods selectively binds lectins and ameloblastin (Ambn) N-terminal antibodies. We tested the hypothesis that ameloblastin N-terminal cleavage products are glycosylated. Assorted Ambn cleavage products showed positive lectin staining by peanut agglutinin (PNA), Maclura pomifera agglutinin (MPA), and Limulus polyphemus agglutinin (LPA), suggesting the presence of an O-linked glycosylation containing galactose (Gal), N-acetylgalactosamine (GalNAc), and sialic acid. Edman sequencing of the lectin-positive bands gave the Ambn N-terminal sequence: VPAFPRQPGTXGVASLXLE. The blank cycles for Pro¹¹ and Ser¹⁷ confirmed that these residues are hydroxylated and phosphorylated, respectively. The O-glycosylation site was determined by Edman sequencing of pronase-digested Ambn, which gave HPPPLPXQPS, indicating that Ser⁸⁶ is the site of the O-linked glycosylation. This modification is within the 15-amino-acid segment (73-YEYSLPVHPPPLPSQ-87) deleted by splicing in the mRNA encoding the 380-amino-acid Ambn isoform. We conclude that only the N-terminal Ambn products derived from the 395-Ambn isoform are glycosylated.

KEY WORDS: ameloblastin • Ambn • sheathlin • enamel • tooth • porcine