Functional specificity of the Antennapedia homeodomain.
The segmental identity in animal development is determined by a set of homeotic selector genes clustered in the invertebrate HOM or vertebrate Hox homeo box complexes. These genes encode proteins with very similar homeodomains and highly diverged N- and C-terminal sequences. The Antennapedia (Antp) homeodomain, for instance, differs at only five amino acid positions from that of Sex combs reduced (Scr) protein. Using a heat shock assay in which chimeric Antp-Scr proteins are expressed ectopically in Drosophila, we have shown that the functional specificity of the Antp protein is determined by the four specific amino acids located in the flexible N-terminal arm of the homeodomain. The three-dimensional structure of the Antp homeodomain-DNA complex shows that this N-terminal arm is located in the minor groove of the DNA, suggesting that the functional specificity is determined either by slight differences in DNA binding and/or by selective interactions with other transcription factor(s).
Furukubo-Tokunaga
K
K
Department of Cell Biology, Biozentrum der Universität Basel, Switzerland.
Flister
S
S
Gehring
W J
WJ
D000595:Amino Acid Sequence; D000818:Animals; D051943:Antennapedia Homeodomain Protein; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins; D005801:Genes, Homeobox; D018398:Homeodomain Proteins; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014157:Transcription Factors; D014170:Transformation, Genetic
D051943:Antennapedia Homeodomain Protein; C497974:Antp protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004247:DNA