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Epithelial‐specific knockout of the Rac1 gene leads to enamel defects
Author(s) -
Huang Zhan,
Kim Jieun,
Lacruz Rodrigo S.,
Bringas Jr Pablo,
Glogauer Michael,
Bromage Timothy G.,
Kaartinen Vesa M.,
Snead Malcolm L.
Publication year - 2011
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2011.00904.x
Subject(s) - ameloblast , amelogenin , enamel paint , rac1 , amelogenesis , enamel organ , knockout mouse , microbiology and biotechnology , chemistry , transgene , biology , gene , dentistry , biochemistry , medicine , signal transduction
Huang Z, Kim J, Lacruz RS, Bringas P Jr, Glogauer M, Bromage TG, Kaartinen VM, Snead ML. Epithelial‐specific knockout of the Rac1 gene leads to enamel defects.
Eur J Oral Sci 2011; 119 (Suppl. 1): 168–176. © 2011 Eur J Oral Sci The Ras‐related C3 botulinum toxin substrate 1 ( Rac1 ) gene encodes a 21‐kDa GTP‐binding protein belonging to the RAS superfamily. RAS members play important roles in controlling focal adhesion complex formation and cytoskeleton contraction, activities with consequences for cell growth, adhesion, migration, and differentiation. To examine the role(s) played by RAC1 protein in cell–matrix interactions and enamel matrix biomineralization, we used the Cre / loxP binary recombination system to characterize the expression of enamel matrix proteins and enamel formation in Rac1 knockout mice ( Rac1 −/− ). Mating between mice bearing the floxed Rac1 allele and mice bearing a cytokeratin 14‐ Cre transgene generated mice in which Rac1 was absent from epithelial organs. Enamel of the Rac1 conditional knockout mouse was characterized by light microscopy, backscattered electron imaging in the scanning electron microscope, microcomputed tomography, and histochemistry. Enamel matrix protein expression was analyzed by western blotting. Major findings showed that the Tomes’ processes of Rac1 −/− ameloblasts lose contact with the forming enamel matrix in unerupted teeth, the amounts of amelogenin and ameloblastin are reduced in Rac1 −/− ameloblasts, and after eruption, the enamel from Rac1 −/− mice displays severe structural defects with a complete loss of enamel. These results support an essential role for RAC1 in the dental epithelium involving cell–matrix interactions and matrix biomineralization.