title: EhPgp5 mRNA stability is a regulatory event in the Entamoeba histolytica multidrug resistance phenotype.
abstract: The multidrug resistance (MDR) phenotype in Entamoeba histolytica is characterized by the overexpression of the EhPgp5 gene in trophozoites grown in high drug concentrations. Here we evaluated the role of EhPgp5 mRNA stability on MDR using actinomycin D. EhPgp5 mRNA from trophozoites growing without emetine had a half-life of 2.1 h, which augmented to 3.1 h in cells cultured with 90 microM and to 7.8 h with 225 microM emetine. Polyadenylation sites were detected at 118-, 156-, and 189-nucleotide (nt) positions of the EhPgp5 mRNA 3'-untranslated region. Interestingly, trophozoites grown with 225 microM emetine exhibited an extra polyadenylation site at 19 nt. The 3'-untranslated region sequence is AU-rich and has putative consensus sequences for RNA-binding proteins. We detected a RNA-protein complex in a region that contains a polypyrimidine tract (142-159 nt) and a cytoplasmic polyadenylation element (146-154 nt). A longer poly(A) tail in the EhPgp5 mRNA was seen in trophozoites grown with 225 microM emetine. Emetine stress may affect factors involved in mRNA turnover, including polyadenylation/deadenylation proteins, which could induce changes in the EhPgp5 mRNA half-life and poly(A) tail length. Novel evidence on mechanisms participating in E. histolytica MDR phenotype is provided.
authors.affiliation: Programa de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatia del Instituto Politécnico Nacional, CP 07300, México, Distrito Federal.
authors.forename: César
authors.initials: C
authors.lastname: López-Camarillo
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Luna-Arias
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Marchat
authors.forename: Esther
authors.initials: E
authors.lastname: Orozco
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D003609:Dactinomycin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004748:Entamoeba histolytica / Q000187:drug effects / Q000235:genetics*; D017125:Genes, Protozoan; D008969:Molecular Sequence Data; D010641:Phenotype; D015800:Protozoan Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D017931:DNA Primers; C459579:EhPgp5 protein, Entamoeba histolytica; D015800:Protozoan Proteins; D012333:RNA, Messenger; D003609:Dactinomycin