An ortholog of the ecdysone receptor protein (EcR) from the parasitic nematode Haemonchus contortus.
High concentrations (> or =4.2mM) of 20E inhibit the development of Haemonchus contortus eggs to the L3 larval stage. We report the cloning of cDNA encoding an EcR ortholog (HcEcR) from H. contortus mRNA expressed during L3. Phylogenetically, this and the putative EcR from Brugia malayi form a separate branch between arthropod EcRs and liver X receptors. Two isoforms of HcEcR differ in the inclusion/omission of a 3-residue segment in the A/B domain. Single nucleotide polymorphisms at 49 positions can be grouped into two major patterns in the A/BC segment and two in the DE/F segment. Some 35% of the highly conserved ecdysteroid-contacting residues in insect EcRs are also conserved in the HcEcR ligand binding domain, but it contains unusual residue choices at other ligand-contacting positions. Recombinant co-expression of HcEcR DE/F segments with a phthirapteran USP DE/F segment in insect cells resulted in stable proteins which did not heterodimerize or bind [(3)H]ponasterone A.
Graham
Lloyd D
LD
CSIRO Food & Nutritional Sciences, P.O. Box 52, North Ryde, NSW 1670, Australia. lloyd.graham@csiro.au
Kotze
Andrew C
AC
Fernley
Ross T
RT
Hill
Ronald J
RJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017178:Brugia malayi / Q000235:genetics; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D019281:Dimerization; D004441:Ecdysterone / Q000031:analogs & derivatives / Q000378:metabolism; D006189:Haemonchus / Q000235:genetics*; D015801:Helminth Proteins / Q000235:genetics*; D007313:Insecta; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary; D011987:Receptors, Steroid / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D018509:DNA, Helminth; D015801:Helminth Proteins; D011987:Receptors, Steroid; D011994:Recombinant Proteins; C055469:ecdysone receptor; D004441:Ecdysterone; C008999:ponasterone A