Isolation of a novel Plasmodium falciparum gene encoding a protein homologous to the Tat-binding protein family.
We have cloned a Plasmodium falciparum gene that belongs to the nuclear Tat-binding protein (TBP) gene family. This gene, PfTBP, is (A + T)-rich and encodes a 49.5-kDa protein. The predicted protein encoded by this gene has highest similarity to the slime mold protein DdTBP10 (86%) and to the yeast protein SUG1 (81.8%), both of which belong to the Tat-binding protein family. In agreement with the characteristics of this family, PfTBP contains a highly conserved domain of approximately 200 amino acids, in which are found the motifs A and B of ATPases, and amino acid sequences characteristic of a large family of RNA or DNA helicases, suggesting a role in RNA or DNA unwinding. Like DdTBP10, the PfTBP protein has a heptad repeat of four leucine residues, reminiscent of a leucine zipper motif known to mediate dimerization. We have further characterized PfTBP gene expression by Northern-blot analysis. This gene is expressed in a stage-specific manner, with higher expression in the late trophozoite stage. The recombinant PfTBP gene has been expressed in Escherichia coli and a polyclonal antiserum has been raised in rabbits against the recombinant protein. This antibody has been used to study the protein in the parasite. The gene product is expressed in a stage-specific manner with higher expression in the late trophozoite and schizont stages, and is localized in the nucleus of the erythrocytic stage parasite. Thus the protein might have a function in DNA synthesis and/or in transcription, as is the case for other Tat-binding proteins.
Hirtzlin
J
J
Department of Structural Biology, University of Basel, Switzerland.
Färber
P M
PM
Franklin
R M
RM
D000074183:ATPases Associated with Diverse Cellular Activities; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D015152:Blotting, Northern; D015153:Blotting, Western; D016384:Consensus Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D017125:Genes, Protozoan; D007930:Leucine; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000254:growth & development; D046988:Proteasome Endopeptidase Complex; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000276:immunology; D012091:Repetitive Sequences, Nucleic Acid; D017385:Sequence Homology
D000906:Antibodies; D016054:DNA, Protozoan; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D046988:Proteasome Endopeptidase Complex; D000074183:ATPases Associated with Diverse Cellular Activities; C064757:PSMC3 protein, human; D007930:Leucine