Transcriptional activation by extradenticle in the Drosophila visceral mesoderm.
decapentaplegic (dpp) is a direct target of Ultrabithorax (Ubx) in parasegment 7 (PS7) of the embryonic visceral mesoderm. We demonstrate that extradenticle (exd) and homothorax (hth) are also required for dpp expression in this location, as well as in PS3, at the site of the developing gastric caecae. A 420 bp element from dpp contains EXD binding sites necessary for expressing a reporter gene in both these locations. Using a specificity swap, we demonstrate that EXD directly activates this element in vivo. Activation does not require Ubx, demonstrating that EXD can activate transcription independently of homeotic proteins. Restoration is restricted to the domains of endogenous dpp expression, despite ubiquitous expression of altered specificity EXD. We demonstrate that nuclear EXD is more extensively phosphorylated than the cytoplasmic form, suggesting that EXD is a target of signal transduction by protein kinases.
Stultz
Brian G
BG
Cellular and Tissue Therapy Branch, Center for Biologics Evaluation and Research, Food and Drug Administration, HFM-730, Bldg. 29B, Rm. 1E16, 8800 Rockville Pike, Bethesda, MD 20892, USA.
Jackson
Donald G
DG
Mortin
Mark A
MA
Yang
Xiang
X
Beachy
Philip A
PA
Hursh
Deborah A
DA
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001665:Binding Sites; D015153:Blotting, Western; D019521:Body Patterning; D002467:Cell Nucleus / Q000378:metabolism; D003433:Crosses, Genetic; D003593:Cytoplasm / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D015180:Electrophoresis, Gel, Two-Dimensional; D004625:Embryo, Nonmammalian / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D015151:Immunoblotting; D007150:Immunohistochemistry; D008648:Mesoderm / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D015533:Transcriptional Activation; D019076:Transgenes; D001616:beta-Galactosidase / Q000378:metabolism
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C064196:dpp protein, Drosophila; C083405:exd protein, Drosophila; D001616:beta-Galactosidase