A Compilation of Partial Sequences of Randomly Selected cDNA Clones from the Rat Incisor

Abstract

The formation of tooth organs is regulated by a series of developmental programs. We have initiated a genome project with the ultimate goal of identifying novel genes important for tooth development. As an initial approach, we constructed a unidirectional cDNA library from the non-calcified portion of incisors of 3- to 4-week-old rats, sequenced cDNA clones, and classified their sequences by homology search through the GenBank data base and the PIR protein data base. Here, we report partial DNA sequences obtained by automated DNA sequencing on 400 cDNA clones randomly selected from the library. Of the sequences determined, 51% represented sequences of new genes that were not related to any previously reported gene. Twenty-six percent of the clones strongly matched genes and proteins in the data bases, including amelogenin, alpha 1(I) and alpha 2(I) collagen chains, osteonectin, and decorin. Nine percent of clones revealed partial sequence homology to known genes such as transcription factors and cell surface receptors. A significant number of the previously identified genes were expressed redundantly and were found to encode extracellular matrix proteins. Identification and cataloging of cDNA clones in these tissues are the first step toward identification of markers expressed in a tissue- or stage-specific manner, as well as the genetic linkage study of tooth anomalies. Further characterization of the clones described in this paper should lead to the discovery of novel genes important for tooth development.

Synthesis, Secretion, Degradation, and Fate of Ameloblastin During the Matrix Formation Stage of the Rat Incisor as Shown by Immunocytochemistry and Immunochemistry Using Region-specific Antibodies

“…Density scans of fluorographs for proteins in the enamel organ at 1 or 10 min after single injections of radioactive methionine and tyrosine have shown that intensity of radiolabeling of this 57-kD protein was the highest next to the 27-kD protein, which corresponds to amelogenin (Smith and Nanci 1996). Matsuki et al (1995) constructed an unidirectional cDNA liberally from the growing end of the rat incisor, sequenced cDNA clones, classified their sequence, and showed that, among the enamel matrix-specific genes, the most redundant mRNAs next to amelogenin were for ameloblastin. These results raise the possibility that ameloblastin corresponds to the sulfated glycoprotein demonstrated by Smith et al (1995).…”

Complementary Roles of Intracellular and Pericellular Collagen Degradation Pathways In Vivo

“…In situ hybridization for collagen types I and II was performed exactly as described previously (20) by using sense and antisense murine collagen type I and II cDNA probes (28,40). In brief, paraffin sections prepared as described above were dewaxed in xylene, rehydrated through a series of EtOH solutions of decreasing concentrations, treated with 5 g/ml proteinase K, postfixed in 4% PFA in phosphate-buffered saline (PBS), acetylated in triethanolamine hydrochloride-acetic anhydride, washed in PBS, dehydrated, and air dried.…”

Cell surface antigen CD109 is a novel member of the α2 macroglobulin/C3, C4, C5 family of thioester-containing proteins

“…A 4 kb EcoRI-XhoI fragment of rat EST R47123 25 was radiolabeled with ␣-32 P-dCTP using the random primer synthesis method 26 and was used to screen a phage Uni-ZAP human umbilical vein endothelial cell (HUVEC) cDNA library (Stratagene, La Jolla, CA). 27 Plaque-purified clones were rescued into pBS SK ϩ by in vivo excision and were amplified, and inserts were evaluated by restriction endonuclease digestion and DNA sequence analysis.…”