title: F-10 nuclear binding proteins of Schistosoma mansoni: structural and functional features.
abstract: By incubating total protein extracts of Schistosoma mansoni with 3H-17-beta-estradiol and 20-hydroxyecdysone, steroid binding proteins were detected in both male and female worms. The interaction of nuclear proteins with a restriction fragment of the gender and stage-specific gene F-10 was investigated using the 'band-shift' technique. Male and female nuclear proteins bound in a distinct way to the fragment of this gene containing putative regulatory consensus motifs. Among the nuclear proteins, only those rich in cysteine residues bound to DNA. In vitro incubation of live worms with the oestrogen antagonist Tamoxifen, altered the pattern of the DNA binding proteins, producing in females a profile similar to that obtained with male worm protein extracts. This effect of Tamoxifen could not be correlated to inhibition of protein biosynthesis. These results suggest that the regulation of transcription of the F-10 gene might involve steroid receptors.
authors.affiliation: Departamento de Bioquímica Médica ICB/CCS, Universidade Federal do Rio de Janeiro, Cidade Universitária-Ilha do Fundão, Brasil.
authors.forename: A L
authors.initials: AL
authors.lastname: Giannini
authors.forename: E C
authors.initials: EC
authors.lastname: Caride
authors.forename: V M
authors.initials: VM
authors.lastname: Braga
authors.forename: F D
authors.initials: FD
authors.lastname: Rumjanek
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004441:Ecdysterone / Q000378:metabolism; D004527:Egg Proteins / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D017238:Genes, Helminth / Q000235:genetics; D015801:Helminth Proteins / Q000378:metabolism*; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism; D011485:Protein Binding; D011987:Receptors, Steroid / Q000378:metabolism; D012550:Schistosoma mansoni / Q000235:genetics / Q000378:metabolism*; D012727:Sex Characteristics; D013629:Tamoxifen / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D004527:Egg Proteins; D015801:Helminth Proteins; D009687:Nuclear Proteins; D011987:Receptors, Steroid; C084248:major eggshell protein F-10, Schistosoma mansoni; D013629:Tamoxifen; D004958:Estradiol; D004441:Ecdysterone