Expression of Dlx genes during the development of the zebrafish pharyngeal dentition: evolutionary implications.
In order to investigate similarities and differences in genetic control of development among teeth within and between species, we determined the expression pattern of all eight Dlx genes of the zebrafish during development of the pharyngeal dentition and compared these data with that reported for mouse molar tooth development. We found that (i) dlx1a and dlx6a are not expressed in teeth, in contrast to their murine orthologs, Dlx1 and Dlx6; (ii) the expression of the six other zebrafish Dlx genes overlaps in time and space, particularly during early morphogenesis; (iii) teeth in different locations and generations within the zebrafish dentition differ in the number of genes expressed; (iv) expression similarities and differences between zebrafish Dlx genes do not clearly follow phylogenetic and linkage relationships; and (v) similarities and differences exist in the expression of zebrafish and mouse Dlx orthologs. Taken together, these results indicate that the Dlx gene family, despite having been involved in vertebrate tooth development for over 400 million years, has undergone extensive diversification of expression of individual genes both within and between dentitions. The latter type of difference may reflect the highly specialized dentition of the mouse relative to that of the zebrafish, and/or genome duplication in the zebrafish lineage facilitating a redistribution of Dlx gene function during odontogenesis.
Borday-Birraux
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V
PGE UPR 9034, CNRS, Gif-sur-Yvette, France.
Van der Heyden
C
C
Debiais-Thibaud
M
M
Verreijdt
L
L
Stock
D W
DW
Huysseune
A
A
Sire
J-Y
JY
D000818:Animals; D005075:Biological Evolution; D001934:Branchial Region / Q000196:embryology*; D003817:Dentition; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics*; D017403:In Situ Hybridization; D051379:Mice; D014070:Tooth / Q000196:embryology*; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000096:biosynthesis / Q000235:genetics
C088334:Distal-less homeobox proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C498152:dlx3b protein, zebrafish; C501122:dlx5a protein, zebrafish; C491015:dlx6a protein, zebrafish