&amp;lt;i&amp;gt;Lef&amp;lt;/i&amp;gt;1 may contribute to agenesis of the third molars in mice

Takehiko Shimizu,Takahiro Ichinosawa,Yuri Kiguchi,Fusae Ishida,Takahide Maeda

doi:10.4236/ojst.2013.35047

Abstract

Tooth agenesis is the most common developmental anomaly of the human dentition. Epilepsy-like disorder (EL) mice, which have a 100% incidence of agenesis of the third molars, may be a good model for the genetic study of human tooth agenesis. Our previous congenic breeding strategy using EL mice confined a major locus for agenesis of M3, designated am3, within an approximately 1 Mega base pair (Mbp) interval on chromosome 3, which contains five known genes; Lef1, Hadh, Cyp2u1, Sgms2 and Papss1. The aim of this study was to identify the strongest candidate for am3 among the five genes using real-time PCR analysis. The tooth germs of M3 in the bud stage of EL and control mice were dissected out, and total RNA was extracted. In real-time PCR analysis, a significantly low level of expression of Lef1, which is one of the essential transcription factors for early tooth development, was observed in M3 of EL mice. In addition, a significantly low level of expression of Fgf4, which is a direct transcriptional target for LEF1 in early tooth development, was observed in M3 of EL mice. Our results suggest that the cause of M3 agenesis of EL mice may be a low level of Lef1 expression in M3 in the bud stage of EL mice.

Highlights

IntroductionThe congenital absence of one or more teeth, is one of the most common craniofacial anomalies in humans
Tooth agenesis, the congenital absence of one or more teeth, is one of the most common craniofacial anomalies in humans
Our results suggest that the cause of M3 agenesis of Epilepsy-like disorder (EL) mice may be a low level of Lef1 expression in M3 in the bud stage of EL mice

Summary

Introduction

The congenital absence of one or more teeth, is one of the most common craniofacial anomalies in humans. The most frequently missing teeth are the third molars, which are absent in around 20% of the population, followed by the mandibular second premolars and maxillary lateral incisors [2]. It appears as both syndromic and non-syndromic/isolated features. Mutations in MSX1 [7], PAX9 [8], AXIN2 [9], WNT10A [10] and the ectodermal dysplasia genes EDA [11], EDAR [12] and EDARADD [13] have been associated with non-syndromic tooth agenesis. In the majority of cases of tooth agenesis, the causes remain unknown [14,15,16,17,18], implying that other genes must be involved

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