Studies in protein evolution have played a significant role in understanding tooth mineralization. In addition, the loss of the self-assembly domains alters the grouping of these crystallites into the enamel rod, the basic building block of enamel. Recent in vitro studies have shown that single amino acid changes in the N-terminus of amelogenin can alter the secondary structure and refolding properties and results in a profile consistent with human amelogenesis imperfecta. Analyses of protein to protein interactions have shown that deletion of either the N- or C- terminus of the amelogenin peptide sequence affects the capacity to assemble into nanospheres. These nanospheres are involved in controlling the enamel crystal habit, by interacting along the c-axis of the growing crystallites to generate high-aspect crystallites and bind them to one another. It is secreted into the extracellular space from the apical end of polarized ameloblast cells where it undergoes self-assembly to form spherical structures referred to as nanospheres. Īmelogenin is the most abundant EMP during enamel development. Soon after, these cells (ameloblasts) express enamel matrix proteins (EMPs) that regulate the development of enamel microstructure by forming an extracellular scaffold that guides mineral growth. Once the tooth follicle has advanced to the bell stage, epithelial cells from the inner enamel epithelium start to elongate and polarize. Tooth development is regulated by a set of conserved genes that determine the number, position, and types of teeth that develop in the oral cavity. In addition, relative to similar-sized anthropoids, lemurs present a fast dental development with several species being born with the milk dentition partially or fully erupted. They are characterized by anatomical features relevant to the dentition, such as the presence of a tooth comb and a distinct dental formula and morphology different to most other primate suborders, tarsiiformes and anthropoidea.
Strepsirrhines are members of a suborder of primates that include lorises, galagos, and lemurs. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: This study was funded by NIH-NIDCR grants to: M.L.P. Received: NovemAccepted: FebruPublished: March 18, 2011Ĭopyright: © 2011 Lacruz et al. PLoS ONE 6(3):Įditor: Vincent Laudet, Ecole Normale Supérieure de Lyon, France (2011) Structural Analysis of a Repetitive Protein Sequence Motif in Strepsirrhine Primate Amelogenin. We speculate that increased AMEL nanosphere size may influence enamel formation in strepsirrhine primates.Ĭitation: Lacruz RS, Lakshminarayanan R, Bromley KM, Hacia JG, Bromage TG, Snead ML, et al. In the monomeric form, the MQP insertions had no influence on the secondary structure or refolding properties, whereas in the assembled form, the insertions increased the hydrodynamic radii. To evaluate the functional relevance of these repeats in strepsirrhines, we engineered a mutated murine amelogenin sequence containing a similar proline-rich sequence to that of Lemur catta. Here, we first determined that these repeats are present in AMEL from three additional lemur species and thus are likely to be widespread throughout this group. Although AMEL has been sequenced in numerous mammalian lineages, the only reported strepsirrhine AMEL sequences are those of the ring-tailed lemur and galago, which contain a set of additional proline-rich tandem repeats absent in all other primates species analyzed to date, but present in some non-primate mammals.
Amelogenin (AMEL), the better known of the enamel matrix proteins, forms 90% of the secreted organic matrix during amelogenesis. Strepsirrhines are members of a primate suborder that has a distinctive set of features associated with the development of the dentition.
0 kommentar(er)
