Dataset Information

Initiator recognition in a primitive eukaryote: IBP39, an initiator-binding protein from Trichomonas vaginalis.

ABSTRACT: While considerable progress has been made in understanding the mechanisms of transcription in higher eukaryotes, transcription in single-celled, primitive eukaryotes remains poorly understood. Promoters of protein-encoding genes in the parasitic protist Trichomonas vaginalis, which represents one of the deepest-branching eukaryotic lineages, have a bipartite structure with gene-specific regulatory elements and a conserved core promoter encompassing the transcription start site. Core promoters in T. vaginalis appear to consist solely of a highly conserved initiator (Inr) element that is both a structural and a functional homologue of its metazoan counterpart. Using DNA affinity chromatography, we have isolated an Inr-binding protein from T. vaginalis. Cloning of the gene encoding the Inr binding protein identified a novel 39-kDa protein (IBP39). We show that IBP39 binds to both double and single Inr motifs found in T. vaginalis genes and that binding requires the conserved nucleotides necessary for Inr function in vivo. Analyses of the cloned IBP39 gene revealed no homology at the protein sequence level with identified proteins in other organisms or the presence of known DNA-binding domains. The relationship between IBP39 and Inr-binding proteins in metazoa presents interesting evolutionary questions.

SUBMITTER: Liston DR

PROVIDER: S-EPMC99959 | biostudies-literature | 2001 Nov

REPOSITORIES: biostudies-literature

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Initiator recognition in a primitive eukaryote: IBP39, an initiator-binding protein from Trichomonas vaginalis.

Liston D R DR Lau A O AO Ortiz D D Smale S T ST Johnson P J PJ

Molecular and cellular biology 20011101 22

While considerable progress has been made in understanding the mechanisms of transcription in higher eukaryotes, transcription in single-celled, primitive eukaryotes remains poorly understood. Promoters of protein-encoding genes in the parasitic protist Trichomonas vaginalis, which represents one of the deepest-branching eukaryotic lineages, have a bipartite structure with gene-specific regulatory elements and a conserved core promoter encompassing the transcription start site. Core promoters in ...[more]

PMID: 11604521

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Project description:Backgroundγ-Carboxymuconolactone decarboxylase (CMD) participates in the β-ketoadipate pathway, which catalyzes aromatic compounds to produce acetyl- or succinyl-CoA, in prokaryotes and yeast. Our previous study demonstrated that expression of a CMD homologue that contains two signatures (dualCMD) is negatively regulated by iron in Trichomonas vaginalis. However, we were not able to identify the components of the β-ketoadipate pathway in the parasite's genome. These observations prompted us to investigate the biological functions of this novel CMD homologue in T. vaginalis.MethodsThe specific anti-TvCMD1 antibody was generated, and the expression of TvCMD1 in T. vaginalis cultured under iron-rich and iron-deficient were evaluated. Phylogenetic, metabolomic and substrate induction (protocatechuate and benzoate) analysis were conducted to clarify the function of dualCMD in trichomonad cells. Subcellular localization of TvCMD1 was observed by confocal microscopy. The cell cycle-related role of TvCMD1 was assessed by treating cells with G2/M inhibitor nocodazole.ResultsWe confirmed that T. vaginalis is not able to catabolize the aromatic compounds benzoate and protocatechuate, which are known substrates of the β-ketoadipate pathway. Using immunofluorescence microscopy, we found that TvCMD1 is spatially associated with the basal body, a part of the cytoskeletal organizing center in T. vaginalis. TvCMD1 accumulated upon treatment with the G2/M inhibitor nocodazole. Additionally, TvCMD1 was expressed and transported to/from the basal body during cytokinesis, suggesting that TvCMD1 plays a role in cell division.ConclusionWe demonstrated that TvCMD1 is unlikely to participate in the β-ketoadipate pathway and demonstrated that it is a novel basal body-localizing (associated) protein. This model sheds light on the importance of genes that are acquired laterally in the coevolution of ancient protists, which surprisingly functions in cell cycle regulation of T. vaginalis.

Dataset Information

Initiator recognition in a primitive eukaryote: IBP39, an initiator-binding protein from Trichomonas vaginalis.

Publications

Initiator recognition in a primitive eukaryote: IBP39, an initiator-binding protein from Trichomonas vaginalis.

Similar Datasets

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