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Woodruff ED, Kircher BK, Armfield BA, Levy JK, Bloch JI, Cohn MJ. Domestic cat embryos reveal unique transcriptomes of developing incisor, canine, and premolar teeth. J Exp Zool B Mol Dev Evol 2022; 338:516-531. [PMID: 35816012 DOI: 10.1002/jez.b.23168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 04/26/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Division of the dentition into morphologically distinct classes of teeth (incisors, canines, premolars, and molars) and the acquisition of tribosphenic molars facilitated precise occlusion between the teeth early in mammal evolution. Despite the evolutionary and ecological importance of distinct classes of teeth with unique cusp, crest, and basin morphologies, relatively little is known about the genetic basis for the development of different tooth classes within the embryo. Here we investigated genetic differences between developing deciduous incisor, canine, and premolar teeth in the domestic cat (Felis catus), which we propose to be a new model for tooth development. We examined differences in both developmental timing and crown morphology between the three tooth classes. Using RNA sequencing of early bell stage tooth germs, we showed that each of the three deciduous tooth classes possess a unique transcriptional profile. Three notable groups of genes emerged from our differential expression analysis; genes involved in the extracellular matrix (ECM), Wnt pathway signaling, and members of multiple homeobox gene families (Lhx, Dlx, Alx, and Nkx). Our results suggest that ECM genes may play a previously under-appreciated role in shaping the surface of the tooth crown during development. Differential regulation of these genes likely underlies differences in tooth crown shape and size, although subtle temporal differences in development between the tooth germs could also be responsible. This study provides foundational data for future experiments to examine the function of these candidate genes in tooth development to directly test their potential effects on crown morphology.
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Affiliation(s)
- Emily D Woodruff
- Department of Biology, University of Florida, Gainesville, Florida, USA
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA
| | - Bonnie K Kircher
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Brooke A Armfield
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Julie K Levy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Jonathan I Bloch
- Department of Biology, University of Florida, Gainesville, Florida, USA
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA
| | - Martin J Cohn
- Department of Biology, University of Florida, Gainesville, Florida, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
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Woodruff ED, Gutierrez GC, Van Otterloo E, Williams T, Cohn MJ. Anomalous incisor morphology indicates tissue-specific roles for Tfap2a and Tfap2b in tooth development. Dev Biol 2021; 472:67-74. [PMID: 33460639 PMCID: PMC8018193 DOI: 10.1016/j.ydbio.2020.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/17/2020] [Accepted: 12/21/2020] [Indexed: 01/13/2023]
Abstract
Mice possess two types of teeth that differ in their cusp patterns; incisors have one cusp and molars have multiple cusps. The patterning of these two types of teeth relies on fine-tuning of the reciprocal molecular signaling between dental epithelial and mesenchymal tissues during embryonic development. The AP-2 transcription factors, particularly Tfap2a and Tfap2b, are essential components of such epithelial-mesenchymal signaling interactions that coordinate craniofacial development in mice and other vertebrates, but little is known about their roles in the regulation of tooth development and shape. Here we demonstrate that incisors and molars differ in their temporal and spatial expression of Tfap2a and Tfap2b. At the bud stage, Tfap2a is expressed in both the epithelium and mesenchyme of the incisors and molars, but Tfap2b expression is restricted to the molar mesenchyme, only later appearing in the incisor epithelium. Tissue-specific deletions show that loss of the epithelial domain of Tfap2a and Tfap2b affects the number and spatial arrangement of the incisors, notably resulting in duplicated lower incisors. In contrast, deletion of these two genes in the mesenchymal domain has little effect on tooth development. Collectively these results implicate epithelial expression of Tfap2a and Tfap2b in regulating the extent of the dental lamina associated with patterning the incisors and suggest that these genes contribute to morphological differences between anterior (incisor) and posterior (molar) teeth within the mammalian dentition.
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Affiliation(s)
- Emily D Woodruff
- Department of Biology, University of Florida, Gainesville, FL, USA.
| | | | - Eric Van Otterloo
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Trevor Williams
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Martin J Cohn
- Department of Biology, University of Florida, Gainesville, FL, USA; Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.
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