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Suppression of polydactyly of the Gli3 mutant (extra toes) by δEF1 homozygous mutation
Author(s) -
Moribe Hiroki,
Takagi Tsuyoshi,
Kondoh Hisato,
Higashi Yujiro
Publication year - 2000
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.2000.00523.x
Subject(s) - gli3 , polydactyly , biology , homeobox , mutant , hox gene , homeotic gene , limb bud , genetics , zinc finger , repressor , gene , gene expression , transcription factor
Digit patterning is established through multiple genetic interactions. δ‐Crystallin enhancer/E2‐box factor (δEF1) is a zinc finger and homeodomain containing repressor protein, and is expressed in the posterior half of the forelimb bud and in the entire hindlimb bud during the early stage of limb development. The δEF1 ‐deficient mutant mice display various skeletal abnormalities, among which inferior ossification and abnormal patterning of autopodial bones are similar to those observed in Hox and Gli gene mutants. Gli3 mutant mice, extra toes ( Xt ), exhibit pre‐axial polydactyly losing the identity of digit I. It is demonstrated here that δEF1 null(lacZ) homozygosity suppressed formation of the extra digit, uniquely of the hindlimb, in both Gli3 XtJ heterozygous and homozygous mutants, but with no restoration of digit I identity. In Gli3 XtJ mutants, the Hoxd13 expression domain was expanded more dramatically in homozygotes. In Gli3 XtJ ;δEF1 null(lacZ) double homozygous mutants, Hoxd13 expression once expanded in Gli3 XtJ homozygous mutant was reduced, more conspicuously in the hindlimbs, which may account for hindlimb‐restricted suppression of formation of the extra digit. The data suggest the possibility that the extent of Hoxd13 expression along the distal margin of the limb bud is determinative in defining the digit number.