Publication in detail

J Biol Chem 2009 Jul 10;284(28):19110-21. Epub 2009 Ma

Hypomaturation enamel defects in Klk4 knockout/LacZ knockin mice.

Hu, JC.; Hu, Y; Lertlam, R; Simmer, JP; Yamakoshi, Y

Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48108, USA.

Abstract:
Kallikrein 4 (Klk4) is believed to play an essential role in enamel biomineralization, because defects in KLK4 cause hypomaturation amelogenesis imperfecta. We used gene targeting to generate a knockin mouse that replaces the Klk4 gene sequence, starting at the translation initiation site, with a lacZ reporter gene. Correct targeting of the transgene was confirmed by Southern blot and PCR analyses. Histochemical X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) staining demonstrated expression of beta-galactosidase in maturation stage ameloblasts. No X-gal staining was observed in secretory stage ameloblasts or in odontoblasts. Retained enamel proteins were observed in the maturation stage enamel of the Klk4 null mouse, but not in the Klk4 heterozygous or wild-type mice. The enamel layer in the Klk4 null mouse was normal in thickness and contained decussating enamel rods but was rapidly abraded following weaning, despite the mice being maintained on soft chow. In function the enamel readily fractured within the initial rod and interrod enamel above the parallel enamel covering the dentino-enamel junction. Despite the lack of Klk4 and the retention of enamel proteins, significant levels of crystal maturation occurred (although delayed), and the enamel achieved a mineral density in some places greater than that detected in bone and dentin. An important finding was that individual enamel crystallites of erupted teeth failed to grow together, interlock, and function as a unit. Instead, individual crystallites seemed to spill out of the enamel when fractured. These results demonstrate that Klk4 is essential for the removal of enamel proteins and the proper maturation of enamel crystals.

ยป Online Version

Proven Track Record

The team at Ozgene has over two decades of experience creating customised knockout and knock-in mice for pivotal medical research globally. Over 350 scientific publications are based on research using Ozgene mice.

Go to Publications

Global Client Base

Ozgene generates genetically customised mice for researchers around the world. Ozgene mice can be found in 31 different countries on 5 continents from small academic institutions to multinational pharmaceutical companies.

See Map

Lean Management

Ozgene is applying Lean Management principles to deliver the highest quality services and shortest lead times to our customers. The implementation of Lean Culture has already seen an improvement in our processes and timelines.

Read More