Differential cooperation between dHAND and three different E-proteins.
dHAND is a transcription factor belonging to the class B basic helix-loop-helix protein family and is expressed during embryogenesis in the heart, branchial arches, limb buds, and neural crest derivatives. Despite much study, the molecular mechanisms involved in the regulation of dHAND activity are not well understood. We therefore carried out yeast two-hybrid screening using full-length dHAND as bait, which led to identification of several dHAND-binding proteins, including three E-proteins: E2A, ME2, and ALF1. Subsequent analysis revealed that although their heterodimerization and transcriptional activities were similar, dHAND/E-protein heterodimers bind to an E-box element with differing affinities, suggesting they have distinct DNA binding specificities. Moreover, in situ hybridization showed that E-protein genes are expressed fairly ubiquitously among embryonic tissues, including the branchial arches and limb buds. By contrast, little signal was detected in the heart, suggesting that dHAND complexes with partners other than E-proteins in cardiac tissue.
Murakami
Masao
M
Division of Integrative Cell Biology, Department of Embryogenesis, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto, Kumamoto 860-0811, Japan.
Kataoka
Keiichiro
K
Tominaga
Junji
J
Nakagawa
Osamu
O
Kurihara
Hiroki
H
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D015153:Blotting, Western; D002460:Cell Line; D004247:DNA / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D019281:Dimerization; D015723:Gene Library; D017930:Genes, Reporter; D005982:Glutathione Transferase / Q000378:metabolism; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D017403:In Situ Hybridization; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D004676:Myelin Basic Protein / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D011485:Protein Binding; D015398:Signal Transduction; D051820:TCF Transcription Factors; D013997:Time Factors; D000073940:Transcription Factor 4; D014157:Transcription Factors / Q000737:chemistry*; D014158:Transcription, Genetic; D014162:Transfection; D020798:Two-Hybrid System Techniques; D029961:Zebrafish Proteins
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D005982:Glutathione Transferase; D008156:Luciferases; D004676:Myelin Basic Protein; D009419:Nerve Tissue Proteins; D051820:TCF Transcription Factors; D000073940:Transcription Factor 4; D014157:Transcription Factors; D029961:Zebrafish Proteins; C498765:HAND2 protein, human; C498766:Hand2 protein, mouse; C407909:TCF3 protein, human; C489532:Tcf12 protein, mouse; C075668:Tcf3 protein, mouse; C090743:Tcf4 protein, mouse; C410915:hand2 protein, zebrafish