title: MEPE Localization in the Craniofacial Complex and Function in Tooth Dentin Formation.
abstract: Matrix extracellular phosphoglycoprotein (MEPE) is an extracellular matrix protein found in dental and skeletal tissues. Although information regarding the role of MEPE in bone and disorders of phosphate metabolism is emerging, the role of MEPE in dental tissues remains unclear. We performed RNA in situ hybridization and immunohistochemistry analyses to delineate the expression pattern of MEPE during embryonic and postnatal development in craniofacial mineralizing tissues. Mepe RNA expression was seen within teeth from cap through root formation in association with odontoblasts and cellular cementoblasts. More intense expression was seen in the alveolar bone within the osteoblasts and osteocytes. MEPE immunohistochemistry showed biphasic dentin staining in incisors and more intense staining in alveolar bone matrix and in forming cartilage. Analysis of Mepe null mouse molars showed overall mineralized tooth volume and density of enamel and dentin comparable with that of wild-type samples. However, Mepe(-/-) molars exhibited increased thickness of predentin, dentin, and enamel over controls and decreased gene expression of Enam, Bsp, Dmp1, Dspp, and Opnby RT-PCR. In vitro Mepe overexpression in odontoblasts led to significant reductions in Dspp reporter activity. These data suggest MEPE may be instrumental in craniofacial and dental matrix maturation, potentially functioning in the maintenance of non-mineralized matrix.
authors.affiliation: Institute of Oral Health Research, Dental School, University of Alabama at Birmingham, Birmingham, Alabama (AG, PS, MM)|Pathology Graduate Program, University of Alabama at Birmingham, Birmingham, Alabama (AG)
authors.forename: Angela
authors.initials: A
authors.lastname: Gullard
authors.affiliation: Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX (JGH)
authors.forename: Jelica
authors.initials: J
authors.lastname: Gluhak-Heinrich
authors.affiliation: Department of Otolaryngology, Medical School, University of Michigan, Ann Arbor, Michigan (SP)
authors.forename: Silvana
authors.initials: S
authors.lastname: Papagerakis
authors.affiliation: Institute of Oral Health Research, Dental School, University of Alabama at Birmingham, Birmingham, Alabama (AG, PS, MM)
authors.forename: Philip
authors.initials: P
authors.lastname: Sohn
authors.affiliation: Department of Developmental Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX (AU)
authors.forename: Aaron
authors.initials: A
authors.lastname: Unterbrink
authors.affiliation: Department of Pediatric Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX (SC),
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.affiliation: Institute of Oral Health Research, Dental School, University of Alabama at Birmingham, Birmingham, Alabama (AG, PS, MM)
authors.forename: Mary
authors.initials: M
authors.lastname: MacDougall
mesh_terms: D000539:Alveolar Process / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D003804:Dentin / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D006023:Glycoproteins / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008810:Mice, Inbred C57BL; D008963:Molar / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism; D010750:Phosphoproteins / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012886:Skull / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; C518716:Mepe protein, mouse; D010750:Phosphoproteins; D012333:RNA, Messenger
keywords: MEPE; alveolar bone; dentin; immunohistochemistry; in situ hybridization; matrix mineralization