title: The 25 kDa subunit of cleavage factor Im Is a RNA-binding protein that interacts with the poly(A) polymerase in Entamoeba histolytica.
abstract: In eukaryotes, polyadenylation of pre-mRNA 3' end is essential for mRNA export, stability and translation. Taking advantage of the knowledge of genomic sequences of Entamoeba histolytica, the protozoan responsible for human amoebiasis, we previously reported the putative polyadenylation machinery of this parasite. Here, we focused on the predicted protein that has the molecular features of the 25 kDa subunit of the Cleavage Factor Im (CFIm25) from other organisms, including the Nudix (nucleoside diphosphate linked to another moiety X) domain, as well as the RNA binding domain and the PAP/PAB interacting region. The recombinant EhCFIm25 protein (rEhCFIm25) was expressed in bacteria and used to generate specific antibodies in rabbit. Subcellular localization assays showed the presence of the endogenous protein in nuclear and cytoplasmic fractions. In RNA electrophoretic mobility shift assays, rEhCFIm25 was able to form specific RNA-protein complexes with the EhPgp5 mRNA 3´ UTR used as probe. In addition, Pull-Down and LC/ESI-MS/MS tandem mass spectrometry assays evidenced that the putative EhCFIm25 was able to interact with the poly(A) polymerase (EhPAP) that is responsible for the synthesis of the poly(A) tail in other eukaryotic cells. By Far-Western experiments, we confirmed the interaction between the putative EhCFIm25 and EhPAP in E. histolytica. Taken altogether, our results showed that the putative EhCFIm25 is a conserved RNA binding protein that interacts with the poly(A) polymerase, another member of the pre-mRNA 3' end processing machinery in this protozoan parasite.
authors.affiliation: Programa Institucional de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía del IPN, Guillermo Massieu Helguera #239, Fracc La Escalera, Ticomán, México DF, Mexico.
authors.forename: Marisol
authors.initials: M
authors.lastname: Pezet-Valdez
authors.forename: Jorge
authors.initials: J
authors.lastname: Fernández-Retana
authors.forename: Juan David
authors.initials: JD
authors.lastname: Ospina-Villa
authors.forename: María Esther
authors.initials: ME
authors.lastname: Ramírez-Moreno
authors.forename: Esther
authors.initials: E
authors.lastname: Orozco
authors.forename: Socorro
authors.initials: S
authors.lastname: Charcas-López
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Soto-Sánchez
authors.forename: Guillermo
authors.initials: G
authors.lastname: Mendoza-Hernández
authors.forename: Mavil
authors.initials: M
authors.lastname: López-Casamicha
authors.forename: César
authors.initials: C
authors.lastname: López-Camarillo
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Marchat
mesh_terms: D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D004748:Entamoeba histolytica / Q000235:genetics* / Q000378:metabolism; D005095:Exoribonucleases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011061:Poly A / Q000235:genetics* / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D039221:mRNA Cleavage and Polyadenylation Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D005095:Exoribonucleases; D011061:Poly A; D021122:Protein Subunits; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D039221:mRNA Cleavage and Polyadenylation Factors