Ac. Zelhof et al., IDENTIFICATION AND CHARACTERIZATION OF A DROSOPHILA NUCLEAR RECEPTOR WITH THE ABILITY TO INHIBIT THE ECDYSONE RESPONSE, Proceedings of the National Academy of Sciences of the United Statesof America, 92(23), 1995, pp. 10477-10481
In a search for retinoid X receptor-like molecules in Drosophila, we h
ave identified an additional member of the nuclear receptor superfamil
y, XR78E/F. In the DNA-binding domain, XR78E/F is closely related to t
he mammalian receptor TR2, as well as to the nuclear receptors Coup-TF
and Seven-up. We demonstrate that XR78E/F binds as a homodimer to dir
ect repeats of the sequence AGGTCA. In transient transfection assays,
XR78E/F represses ecdysone signaling in a DNA-binding-dependent fashio
n. XR78E/F has its highest expression in third-instar larvae and prepu
pae. These experiments suggest that XR78E/F may play a regulatory role
in the transcriptional cascade triggered by the hormone ecdysone in D
rosophila.