TY - JOUR
T1 - Cubitus interruptus requires Drosophila CREB-binding protein to activate wingless expression in the Drosophila embryo
AU - Chen, Yang
AU - Goodman, R. H.
AU - Smolik, Sarah M.
PY - 2000/3
Y1 - 2000/3
N2 - CREB-binding protein (CBP) serves as a transcriptional coactivator in multiple signal transduction pathways. The Drosophila homologue of CBP, dCBP, interacts with the transcription factors Cubitus interruptus (CI), MAD, and Dorsal (DL) and functions as a coactivator in several signaling pathways during Drosophila development, including the hedgehog (hh), decapentaplegic (dpp), and Toll pathways. Although dCBP is required for the expression of the hh target genes, wingless (wg) and patched (ptc) in vivo, and potentiates ci- mediated transcriptional activation in vitro, it is not known that ci absolutely requires dCBP for its activity. We used a yeast genetic screen to identify several ci point mutations that disrupt CI-dCBP interactions. These mutant proteins are unable to transactivate a reporter gene regulated by ci binding sites and have a lower dCBP-stimulated activity than wild-type CI. When expressed exogenously in embryos, the CI point mutants cannot activate endogenous wg expression. Furthermore, a CI mutant protein that lacks the entire dCBP interaction domain functions as a negative competitor for wild- type CI activity, and the expression of dCBP antisense RNAs can suppress CI transactivation in Kc cells. Taken together, our data suggest that dCBP function is necessary for ci-mediated transactivation of wg during Drosophila embryogenesis.
AB - CREB-binding protein (CBP) serves as a transcriptional coactivator in multiple signal transduction pathways. The Drosophila homologue of CBP, dCBP, interacts with the transcription factors Cubitus interruptus (CI), MAD, and Dorsal (DL) and functions as a coactivator in several signaling pathways during Drosophila development, including the hedgehog (hh), decapentaplegic (dpp), and Toll pathways. Although dCBP is required for the expression of the hh target genes, wingless (wg) and patched (ptc) in vivo, and potentiates ci- mediated transcriptional activation in vitro, it is not known that ci absolutely requires dCBP for its activity. We used a yeast genetic screen to identify several ci point mutations that disrupt CI-dCBP interactions. These mutant proteins are unable to transactivate a reporter gene regulated by ci binding sites and have a lower dCBP-stimulated activity than wild-type CI. When expressed exogenously in embryos, the CI point mutants cannot activate endogenous wg expression. Furthermore, a CI mutant protein that lacks the entire dCBP interaction domain functions as a negative competitor for wild- type CI activity, and the expression of dCBP antisense RNAs can suppress CI transactivation in Kc cells. Taken together, our data suggest that dCBP function is necessary for ci-mediated transactivation of wg during Drosophila embryogenesis.
UR - http://www.scopus.com/inward/record.url?scp=0033969466&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033969466&partnerID=8YFLogxK
U2 - 10.1128/MCB.20.5.1616-1625.2000
DO - 10.1128/MCB.20.5.1616-1625.2000
M3 - Article
C2 - 10669739
AN - SCOPUS:0033969466
SN - 0270-7306
VL - 20
SP - 1616
EP - 1625
JO - Molecular and cellular biology
JF - Molecular and cellular biology
IS - 5
ER -