title: Chymotrypsin C (caldecrin) is associated with enamel development.
abstract: Two main proteases cleave enamel extracellular matrix proteins during amelogenesis. Matrix metalloprotease-20 (Mmp20) is the predominant enzyme expressed during the secretory stage, while kallikrein-related peptidase-4 (Klk4) is predominantly expressed during maturation. Mutations to both Mmp20 and Klk4 result in abnormal enamel phenotypes. During a recent whole-genome microarray analysis of rat incisor enamel organ cells derived from the secretory and maturation stages of amelogenesis, the serine protease chymotrypsin C (caldecrin, Ctrc) was identified as significantly up-regulated (> 11-fold) during enamel maturation. Prior reports indicate that Ctrc expression is pancreas-specific, albeit low levels were also noted in brain. We here report on the expression of Ctrc in the enamel organ. Quantitative PCR (qPCR) and Western blot analysis were used to confirm the expression of Ctrc in the developing enamel organ. The expression profile of Ctrc is similar to that of Klk4, increasing markedly during the maturation stage relative to the secretory stage, although levels of Ctrc mRNA are lower than for Klk4. The discovery of a new serine protease possibly involved in enamel development has important implications for our understanding of the factors that regulate enamel biomineralization.
authors.affiliation: Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, USA. rodrigo@usc.edu
authors.forename: R S
authors.initials: RS
authors.lastname: Lacruz
authors.forename: C E
authors.initials: CE
authors.lastname: Smith
authors.forename: S M
authors.initials: SM
authors.lastname: Smith
authors.forename: P
authors.initials: P
authors.lastname: Hu
authors.forename: P
authors.initials: P
authors.lastname: Bringas
authors.forename: M
authors.initials: M
authors.lastname: Sahin-Tóth
authors.forename: J
authors.initials: J
authors.lastname: Moradian-Oldak
authors.forename: M L
authors.initials: ML
authors.lastname: Paine
mesh_terms: D000566:Amelogenesis / Q000235:genetics*; D000818:Animals; D015153:Blotting, Western; D002918:Chymotrypsin / Q000096:biosynthesis* / Q000235:genetics*; D003746:Dental Enamel Proteins / Q000096:biosynthesis* / Q000235:genetics; D004658:Enamel Organ / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007610:Kallikreins / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D053519:Matrix Metalloproteinase 20 / Q000096:biosynthesis / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation
chemical_list: D003746:Dental Enamel Proteins; D012333:RNA, Messenger; C109069:enamel matrix proteins; D007610:Kallikreins; C120801:kallikrein 4; D002918:Chymotrypsin; C117569:chymotrypsin C; D053519:Matrix Metalloproteinase 20