Figure 1.

Evc2 mutant mice showed hypomorphic enamel formation. (A) Mutant alleles of Evc2/Limbin used in this study. Ex12-Stop (a global knockout allele), a stop codon, along with an IRES-LacZ cassette has been inserted into exon 12 to mimic a nonsense mutation identified in human patients. Floxed (a conditional allele) and 2 loxP sites have been introduced to flank exon 13 and exon 14. A Cre-mediated recombination results in a frame shift downstream of exon 12 of Evc2. dE, a Cre recombined allele, produces a similarly truncated EVC2 protein with the one from Ex12-Stop allele, if any. (B) LacZ staining of Evc2 ^ex12/+ incisor indicates that Evc2 is expressed in dental epithelium, mesenchyme, and surrounding bone tissue. (C) Lateral X-ray radiogram of 2-mo-old Evc2 mutant mice shows hypomorphic maxilla and mandible incisor formations (top). Frontal view and side view of the same mice demonstrate possible hypomorphic enamel in Evc2 mutant mice (bottom). Yellow dashed lines indicate maxilla incisors and blue dashed lines indicate mandible incisors. (D) Lateral X-ray radiogram of 2-mo-old dissected maxilla and mandible shows hypomorphic incisor and molar formation in Evc2 mutant. Yellow dashed lines indicate maxilla incisors and blue dashed lines indicate mandible incisors.