Expression of ephrin-A ligands and EphA receptors in the developing mouse tooth and its supporting tissues.

Abstract

Ephrins are cell-membrane-bound ligands for Eph receptor tyrosine kinases and regulate a variety of developmental processes. In order to investigate the potential roles of the ephrin-Eph system in tooth formation, we studied the cellular mRNA expression of Ephrin-A1-A5 and EphA2, EphA3, EphA4, EphA7, and EphA8 receptors during embryonic histomorphogenesis of the mouse first molar (embryonic days 11.5-18.5). Ephrin-A1, ephrin-A5, EphA2, EphA3, EphA4, and EphA7 were expressed in the tooth germ at the epithelial thickening stage, and later, ephrin-A1, ephrin-A5, EphA2, EphA4, and EphA7 showed distinct expression patterns in the enamel organ undergoing epithelial folding morphogenesis. Prior to birth, ephrin-A1, ephrin-A5, EphA2, and EphA4 transcripts were present in the cuspal area of the dental papilla including the preodontoblasts. In addition, ephrin-A1 and ephrin-A5 were seen in the forming blood vessels and alveolar bone, respectively. In contrast, ephrin-A2, ephrin-A3, and ephrin-A4 showed ubiquitous expression during odontogenesis, whereas EphA8 transcripts were not observed. During dental trigeminal axon pathfinding (embryonic days 12.5-13.5), ephrin-A2, ephrin-A4, and ephrin-A5 were evenly distributed in the trigeminal ganglion, whereas EphA7 was expressed in a subset of ganglion cells. These results suggest regulatory roles for ephrin-A/EphA signaling in the formation of the tooth organ proper and its supporting tissues.

• Authors: Keijo Luukko, Sigbjørn Løes, Inger Hals Kvinnsland, Päivi Kettunen
• Journal: Cell and tissue research (Cell Tissue Res) Vol. 319 Issue 1 Pg. 143-52 (Jan 2005) ISSN: 0302-766X [Print] Germany
• PMID: 15517401 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ephrins
• Ligands
• RNA, Messenger
• Receptors, Eph Family

Topics

• Animals
• Dental Enamel (cytology, embryology, metabolism)
• Ephrins (biosynthesis, genetics)
• Gene Expression Regulation, Developmental
• In Situ Hybridization
• Ligands
• Mandible (embryology)
• Mice
• Molar (cytology, embryology, metabolism)
• Odontoblasts (cytology, metabolism)
• Odontogenesis
• RNA, Messenger (biosynthesis)
• Receptors, Eph Family (biosynthesis, genetics)
• Trigeminal Ganglion (cytology, embryology, metabolism)