Entamoeba histolytica: a unicellular organism containing two active genes encoding for members of the TBP family.
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.
Castañon-Sanchez
Carlos Alberto
CA
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.
Luna-Arias
Juan Pedro
JP
de Dios-Bravo
Ma Guadalupe
MG
Herrera-Aguirre
Maria Esther
ME
Olivares-Trejo
Jose J
JJ
Orozco
Esther
E
Hernandez
Jose Manuel
JM
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
D015800:Protozoan Proteins; D035182:TATA Box Binding Protein-Like Proteins; D035181:TATA-Box Binding Protein