Role of Dlx6 in regulation of an endothelin-1-dependent, dHAND branchial arch enhancer.
Neural crest cells play a key role in craniofacial development. The endothelin family of secreted polypeptides regulates development of several neural crest sublineages, including the branchial arch neural crest. The basic helix-loop-helix transcription factor dHAND is also required for craniofacial development, and in endothelin-1 (ET-1) mutant embryos, dHAND expression in the branchial arches is down-regulated, implicating it as a transcriptional effector of ET-1 action. To determine the mechanism that links ET-1 signaling to dHAND transcription, we analyzed the dHAND gene for cis-regulatory elements that control transcription in the branchial arches. We describe an evolutionarily conserved dHAND enhancer that requires ET-1 signaling for activity. This enhancer contains four homeodomain binding sites that are required for branchial arch expression. By comparing protein binding to these sites in branchial arch extracts from endothelin receptor A (EdnrA) mutant and wild-type mouse embryos, we identified Dlx6, a member of the Distal-less family of homeodomain proteins, as an ET-1-dependent binding factor. Consistent with this conclusion, Dlx6 was down-regulated in branchial arches from EdnrA mutant mice. These results suggest that Dlx6 acts as an intermediary between ET-1 signaling and dHAND transcription during craniofacial morphogenesis.
Charité
J
J
Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75239-9148, USA.
McFadden
D G
DG
Merlo
G
G
Levi
G
G
Clouthier
D E
DE
Yanagisawa
M
M
Richardson
J A
JA
Olson
E N
EN
D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D001665:Binding Sites; D019556:COS Cells; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D015536:Down-Regulation; D019332:Endothelin-1 / Q000378:metabolism*; D017353:Gene Deletion; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000378:metabolism* / Q000502:physiology*; D017403:In Situ Hybridization; D051379:Mice; D008822:Mice, Transgenic; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D029961:Zebrafish Proteins
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D019332:Endothelin-1; D018398:Homeodomain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C100597:Dlx6 protein, mouse; C498766:Hand2 protein, mouse; C410915:hand2 protein, zebrafish