designated phx3 5 subcloned and sequenced the deduced amino acid sequence of one of the reading frames in phx3 5 had the structural features of asteroid receptor dna binding domain phx3 5 was used as a probe to screen a total third instar larval imaginal disc cdna library from d melanogaster in the ecori site of bluescriptr phagemid sk stratagene la jolla calif usa six cdna clones were identified by this procedure the complete nucleotide sequence of the longest designated pxr2c8 except for the overhanging ecori ends is presented in seq id no 1 along with the deduced amino acid sequence of the 513 amino acid xr2c encoded by the segment of pxr2c8 from nucleotides 163 1701 the gene for xr2c has been mapped to the ultraspiracle locus of d melanogaster indicating that function of the xr2c receptor is essential for normal development and that interruption of the function early in development would be lethal amino acid sequences of xr2c hrxr alpha commonly owned united states patent application ser no 478 071 filed feb 9 1990 now abandoned in favor of continuation in part u s ser no 07 933 453 filed aug 21 1992 now abandoned in favor of file wrapper continuation application u s ser no 08 336 408 filed nov 8 1994 incorporated herein by reference hrar alpha human retinoic acid receptor alpha giguere et al nature 330 624 1987 commonly asigned united states patent application ser no 276 536 filed nov 30 1988 issued jan 1 1991 as united states pat no 5 071 773 european patent application publication no 0 325 849 all incorporated herein by reference and hgr human glucocorticoid receptor hollenberg et al nature 318 635 1985 commonly assigned united states.