A steroid/thyroid hormone receptor superfamily member in Drosophila melanogaster that shares extensive sequence similarity with a mammalian homologue

Vincent C. Henrich, Timothy J. Sliter, Dennis B. Lubahn, Alanna MacIntyre, Lawrence I. Gilbert

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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 hormonebinding 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.

Original languageEnglish (US)
Pages (from-to)4143-4148
Number of pages6
JournalNucleic Acids Research
Volume18
Issue number14
Publication statusPublished - Jul 25 1990

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ASJC Scopus subject areas

  • Genetics
  • Statistics, Probability and Uncertainty
  • Applied Mathematics
  • Health, Toxicology and Mutagenesis
  • Toxicology
  • Genetics(clinical)

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