This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Bouropoulos, N. Articles by Moradian-Oldak, J. Search for Related Content PubMed PubMed Citation Articles by Bouropoulos, N. Articles by Moradian-Oldak, J. Social Bookmarking                         What's this?

Induction of Apatite by the Cooperative Effect of Amelogenin and the 32-kDa Enamelin

Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033;

View larger version (30K): [in this window] [in a new window]   Figure 1. In vitro experimental set-up for the nucleation of apatite by amelogenins and the 32-kDa enamelin. (A) Sodium dodecyl sulfate-polyacrylamide gel (15% acrylamide) electrophoresis (SDS-PAGE) patterns of extracted amelogenins and the 32-kDa enamelin. Lane 1: Gibco BRL protein molecular-weight standard containing proteins with 43-k, 29-k, 18-k, 14-k, and 5-k molecular weights. Lane 2: amelogenins extracted from the extracellular enamel matrix of developing pig mandibular molars by the dissociative technique as described in MATERIALS & METHODS. The extract was characterized to be a mixture of secreted amelogenin (25 K, 7.4%) and its processed products (23 K, 10.7%; 20 K [the major band], 49.5%; 14–18 kDa, 32.4%) (Wen et al., 1999). Lane 3: The 32-KDa enamelin with an apparent molecular weight of 32 kDa. (B) Schematic representation for the experimental set-up used for monitoring nucleation of apatite crystals. Induction time was determined based on the difference in calcium uptake by the gel between the control (without phosphate) and the samples (with phosphate) as described in Fig. 3.

View larger version (138K): [in this window] [in a new window]   Figure 2. Transmission electron micrograph of crystals grown in 10% gelatin-1.5% amelogenin gel, indicating the formation of apatite crystals. The insert shows the corresponding electron diffraction pattern. The arrowhead reflections 1 and 2 correspond to lattice spacings of 3.44 and 2.74 Å, respectively, which are characteristic of hydroxyapatite.

View larger version (12K): [in this window] [in a new window]   Figure 3. Uptake of calcium ions from the upper solution by gelatin gel containing 1.5% amelogenin with (, sample) and without (, control) phosphate ions. Comparisons between the sample and the control for each measurement were made by Student’s t test, and statistically significant differences were defined at p < 0.05. Induction time was defined as the time when the comparison between the sample (phosphate-containing gel) and the control for each measurement was statistically significant. Values are based on ratio percentages of 45Ca radioactivity (counts per min) at time t to that measured at time zero as the function of time. The data (13 points) shown are the mean ± SD of 3 separate experiments. The variability ranged between SD = 0.4–1.9 for control and SD = 0.3–2.3 for sample.

Journal of Dental Research, Vol. 83, No. 4, 278-282 (2004)
DOI: 10.1177/154405910408300402


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?