title: A steroid/thyroid hormone receptor superfamily member in Drosophila melanogaster that shares extensive sequence similarity with a mammalian homologue.
abstract: A gene in Drosophila melanogaster that maps cytologically to 2C1-3 on the distal portion of the X-chromosome encodes a member of the steroid/thyroid hormone receptor superfamily. The gene was isolated from an embryonic cDNA library using an oligonucleotide probe that specifies the consensus amino acid sequence in the DNA-binding domain of several human receptors. The conceptual amino acid sequence of 2C reveals at least four regions of homology that are shared with all identified vertebrate receptors. Region I includes the two cysteine-cysteine zinc fingers that comprise a DNA-binding domain which typifies all members of the superfamily. In addition, three regions (Regions II-IV) in the carboxy-terminal portion of the protein that encode the putative hormone-binding domain of the 2C gene product resemble similar sequences in vertebrate steroid/thyroid hormone receptors. The similarity suggests that this Drosophila receptor possesses many of the regulatory functions attributed to these regions in vertebrate counterparts. A portion of Region II also resembles part of the human c-jun oncoprotein's leucine zipper, which in turn, has been demonstrated to be the heterodimerization site between the jun and fos oncoproteins. The 2C receptor-like protein most resembles the mouse H2RII binding protein, a member of the superfamily which has been implicated in the regulation of major histocompatibility complex (MHC) class I gene expression. These two gene products are 83% identical in the DNA-binding domain and 50% identical in the putative hormone-binding domain, although no ligand has been identified for either protein. The high degree of similarity in the hormone-binding domain between the 2C protein and the H2RII binding protein outside regions II-IV suggests specific functional roles which are not shared by other members of the superfamily.
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill 27599-3280.
authors.forename: V C
authors.initials: VC
authors.lastname: Henrich
authors.forename: T J
authors.initials: TJ
authors.lastname: Sliter
authors.forename: D B
authors.initials: DB
authors.lastname: Lubahn
authors.forename: A
authors.initials: A
authors.lastname: MacIntyre
authors.forename: L I
authors.initials: LI
authors.lastname: Gilbert
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics*; D005796:Genes; D008969:Molecular Sequence Data; D005810:Multigene Family; D011956:Receptors, Cell Surface / Q000235:genetics*; D011988:Receptors, Thyroid Hormone / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D011956:Receptors, Cell Surface; D011988:Receptors, Thyroid Hormone; D004247:DNA