In recent years a number of new genes have been identified that are involved in tooth morphogenesis. Though much progress has been made in identifying new genes and the signaling mechanisms that regulate morphogenetic stages of tooth development have been documented, the transcriptional mechanisms that regulate cytodifferentiation of the odontoblasts and ameloblasts are poorly understood. Better understanding of the mechanistic aspect of this process is necessary, not only to understand normal tooth morphogenesis, but also to regenerate teeth, and eventually be able to develop and deliver better therapeutic strategies. Our lab has identified FoxJ1 as a new transcription factor involved in late stage tooth and craniofacial morphogenesis. FoxJ1 (also known as HFH-4, FHKL-13) belongs to the fork-head family of genes, containing a fork-head (also known as winged helix) DNA binding domain is known to regulate development via cell fate determination. Our preliminary data reveals FoxJ1 expression in the mouse molar inner dental epithelium from E18.5 onwards and in the pre-ameloblasts and odontoblasts during neonate day 1. It is also expressed in the oral epithelium and sub-mandibular salivary gland during E17.5 and neonate day 1. Our transient transfection data indicates that FoxJ1 is activated by, and also physically interacts with PITX2, a homeobox transcription factor gene involved in early craniofacial/tooth development. The overall goal of this proposal is to test our hypothesis that FoxJ1 plays a role in cytodifferentiation of ameloblasts and odontoblasts during tooth development using mouse genetics. We will test our hypothesis that PITX2 regulates FoxJ1 expression in concert with other transcription factors during tooth development. Moreover, FoxJ1 physically interacts with PITX2 and auto-regulates its promoter in a positive feed back fashion. We will test our hypothesis that FoxJ1 interacts with PITX2 and other tooth specific transcription factors to regulate late bell and pre-secretory stages of tooth development.The identification of new genes involved in craniofacial/tooth development will increase our knowledge about the basic development programs required for normal embryogenesis. Understanding how these components interact to promote normal craniofacial development will further our understanding of genetic defects. We can then promote methodologies to inhibit severe craniofacial anomalies. PERFORMANCE SITE(S) (organization, city, state) Texas A&M Health Science Center, Institute for Biosciences and Technology, Houston, TX PHS 398 (Rev. 04/06) Page 2 Form Page 2

Public Health Relevance

The identification of new genes involved in craniofacial/tooth development will increase our knowledge about the basic development programs required for normal embryogenesis. Understanding how these components interact to promote normal craniofacial development will further our understanding of genetic defects. We can then promote methodologies to inhibit severe craniofacial anomalies once a molecular basis has been assigned to a specific defect or component.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
7R01DE018885-04
Application #
8246305
Study Section
Special Emphasis Panel (ZRG1-MOSS-K (09))
Program Officer
Scholnick, Steven
Project Start
2009-07-01
Project End
2012-07-31
Budget Start
2012-04-01
Budget End
2012-07-31
Support Year
4
Fiscal Year
2012
Total Cost
$151,601
Indirect Cost
$48,119
Name
Texas A&M University
Department
Genetics
Type
Schools of Medicine
DUNS #
835607441
City
College Station
State
TX
Country
United States
Zip Code
77845
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