title: Entamoeba histolytica: a unicellular organism containing two active genes encoding for members of the TBP family.
abstract: Entamoeba histolytica is the protozoan parasite which causes human amoebiasis. In this parasite, few encoding genes for transcription factors have been cloned and characterized. The E. histolytica TATA-box binding protein (EhTBP) is the first basal transcription factor that has been studied. To continue with the identification of other members of the basal transcription machinery, we performed an in silico analysis of the E. histolytica genome and found three loci encoding for polypeptides with similarity to EhTBP. One locus has a 100% identity to the previously Ehtbp gene reported by our group. The second locus encodes for a 212 aa polypeptide that is 100% identical to residues 23-234 from EhTBP. The third one encodes for a 216 aa polypeptide of 24kDa that showed 42.6% identity and 73.7% similarity to EhTBP. This protein was named E. histolytica TBP-related factor 1 (EhTRF1). Ehtrf1 gene was expressed in bacteria and the purified 28kDa recombinant polypeptide showed the capacity to bind to TATTTAAA-box by electrophoretic mobility shift assays. K(D) values for rEhTBP and rEhTRF1 were (1.71+/-2.90)x10(-12)M and (1.12+/-0.160)x10(-11)M, respectively. Homology modeling of EhTRF1 and EhTBP revealed that, although they were very similar, they showed some differences on their surfaces. Thus, E. histolytica is a unicellular organism having two members of the TBP family.
authors.affiliation: Programa Institucional de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía, IPN, Guillermo Massieu Helguera 239, Fracc. La Escalera, Ticomán, CP 07320, México, D.F., Mexico.
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Castañon-Sanchez
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Luna-Arias
authors.forename: Ma Guadalupe
authors.initials: MG
authors.lastname: de Dios-Bravo
authors.forename: Maria Esther
authors.initials: ME
authors.lastname: Herrera-Aguirre
authors.forename: Jose J
authors.initials: JJ
authors.lastname: Olivares-Trejo
authors.forename: Esther
authors.initials: E
authors.lastname: Orozco
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Hernandez
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D024202:Electrophoretic Mobility Shift Assay; D004748:Entamoeba histolytica / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D035182:TATA Box Binding Protein-Like Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D035181:TATA-Box Binding Protein / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D035182:TATA Box Binding Protein-Like Proteins; D035181:TATA-Box Binding Protein