Involvement of multiple DNA elements in iron‐inducible transcription of the <i>ap65‐1</i> gene in the protozoan parasite <i>Trichomonas vaginalis</i>

Ong, Shiou-Jeng; Huang, Shen-Chi; Liu, Hsing-Wei; Tai, Jung-Hsiang

doi:10.1111/j.1365-2958.2004.04088.x

Cited by 21 publications

(32 citation statements)

References 35 publications

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“…Plasmids were transfected into T. vaginalis for paromomycin selection of stable transfectants, and cloned cell lines were established as previously described (28).…”

Section: Methodsmentioning

confidence: 99%

“…To date, multiple parasitic factors that contribute to cytoadherence, including some carbohydrate moieties and several reputed adhesion proteins on plasma membranes, have been identified (1-6, 16, 26). Serial studies on inducible transcription of the adhesion protein gene, ap65-1, revealed that its transcription is critically coregulated by three Myb proteins, Myb1, Myb2, and Myb3, through competitive entries of multiple Myb recognition elements in the distal promoter region in a space-and time-dependent manner (18,(28)(29)(30)38), suggesting that these Myb proteins are differentially regulated in response to various stimuli from host environments. Myb proteins are ubiquitous in eukaryotes that share a conserved DNA-binding domain (DBD) composed of one to three repeat sequences termed R1, R2R3, and R1R2R3.…”

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confidence: 99%

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Iron-Inducible Nuclear Translocation of a Myb3 Transcription Factor in the Protozoan Parasite Trichomonas vaginalis

Hsu

Indra

et al. 2012

Eukaryot Cell

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cIn Trichomonas vaginalis, a novel nuclear localization signal spanning the folded R2R3 DNA-binding domain of a Myb2 protein was previously identified. To study whether a similar signal is used for nuclear translocation by other Myb proteins, nuclear translocation of Myb3 was examined in this report. When overexpressed, hemagglutinin-tagged Myb3 was localized to nuclei of transfected cells, with a cellular distribution similar to that of endogenous Myb3. Fusion to a bacterial tetracycline repressor, R2R3, of Myb3 that spans amino acids (aa) 48 to 156 was insufficient for nuclear translocation of the fusion protein, unless its C terminus was extended to aa 167. The conserved isoleucine in helix 2 of R2R3, which is important for Myb2's structural integrity in maintaining DNA-binding activity and nuclear translocation, was also vital for the former activity of Myb3, but less crucial for the latter. Sequential nuclear influx and efflux of Myb3, which require further extension of the nuclear localization signal to aa 180, were immediately induced after iron repletion. Sequence elements that regulate nuclear translocation with cytoplasmic retention, nuclear influx, and nuclear efflux were identified within the C-terminal tail. These results suggest that the R2R3 DNAbinding domain also serves as a common module for the nuclear translocation of both Myb2 and Myb3, but there are intrinsic differences between the two nuclear localization signals.

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“…Plasmids were transfected into T. vaginalis for paromomycin selection of stable transfectants, and cloned cell lines were established as previously described (28).…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Iron-Inducible Nuclear Translocation of a Myb3 Transcription Factor in the Protozoan Parasite Trichomonas vaginalis

Hsu

Indra

et al. 2012

Eukaryot Cell

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“…IR completely competed for the complexes, but they were removed only partially by some of the mutant competitors. The signal intensities of the complexes in individual reaction mixtures were measured, revealing that rMyb3 interacts with the core DNA sequence, TAACGA, which resembles the target site of the reputed MRE-1-binding proteins (26). Sequences flanking the core may also contribute to optimizing interactions between Myb3 and MRE-1.…”

Section: Identification Of An Mre-1/mre-2r-binding Proteinmentioning

confidence: 99%

“…Plasmids were electroporated into T. vaginalis for paromomycin selection of stable transfectants, and cloned cell lines were established as previously described (26).…”

Section: Culturesmentioning

confidence: 99%

“…For example, two discrete Myb protein-recognition sites, MRE-1/MRE-2r and MRE-2f, which are interspersed among several closely spaced DNA elements in the iron-responsive promoter region (Ϫ132 to Ϫ37 nucleotides from the transcription initiation site) of a malic enzyme gene (also reputed to be ap65-1), which encodes a 65-kDa hydrogenosomal malic enzyme that might have an ambiguous role in the cytoadherence of the parasite (4,13), were demonstrated to play crucial roles in temporal and ironinducible ap65-1 transcription (24)(25)(26)32). MRE-1/MRE-2r and MRE-2f share similar but oppositely oriented DNA sequences, each of which is also the target site for several distinct Myb-like proteins (24)(25)(26). Two of these DNA-binding proteins, Myb1 and Myb2, which were identified by Southwestern library screening using a probe with concatenated MRE-2f sequences (25), were found to pose antagonistic actions on basal and iron-inducible transcription of the ap65-1 gene through dual recognition and differential promoter selection toward the MRE-1/MRE-2r and MRE-2f sites (24,25).…”

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Transcriptional Regulation of an Iron-Inducible Gene by Differential and Alternate Promoter Entries of Multiple Myb Proteins in the Protozoan Parasite Trichomonas vaginalis

et al. 2009

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Iron-inducible transcription of a malic enzyme gene (also reputed to be ap65-1) in Trichomonas vaginalis was previously shown to involve a Myb1 repressor and a Myb2 activator, each of which may preferentially select two closely spaced promoter sites, MRE-1/MRE-2r, which comprises overlapping promoter elements, and MRE-2f. In the present study, an iron-inducible ϳ32-kDa Myb3 nuclear protein was demonstrated to bind only the MRE-1 element. Changes in the iron supply, which produced antagonistic effects on the levels of Myb2 and Myb3 expression, also resulted in temporal and alternate entries of Myb2 and Myb3 into the ap65-1 promoter. Repression or activation of basal and iron-inducible ap65-1 transcription was detected in transfected cells when Myb3 was, respectively, substantially knocked down or overexpressed. In the latter case, increased Myb3 promoter entry was detected with concomitant decrease in Myb2 promoter entry under specific conditions, while Myb3 promoter entry was inhibited under all test conditions in cells overexpressing Myb2. In contrast, concomitant promoter entries by Myb2 and Myb3 diminished in cells overexpressing Myb1, except that Myb3 promoter entry was slightly affected under prolonged iron depletion. Together, these results suggest that Myb2 and Myb3 may coactivate basal and iron-inducible ap65-1 transcription against Myb1 through conditional and competitive promoter entries.

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An in vitro characterisation of the Trichomonas vaginalis TATA box-binding proteins (TBPs)

et al. 2019

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Involvement of multiple DNA elements in iron‐inducible transcription of the ap65‐1 gene in the protozoan parasite Trichomonas vaginalis

Cited by 21 publications

References 35 publications

Iron-Inducible Nuclear Translocation of a Myb3 Transcription Factor in the Protozoan Parasite Trichomonas vaginalis

Iron-Inducible Nuclear Translocation of a Myb3 Transcription Factor in the Protozoan Parasite Trichomonas vaginalis

Transcriptional Regulation of an Iron-Inducible Gene by Differential and Alternate Promoter Entries of Multiple Myb Proteins in the Protozoan Parasite Trichomonas vaginalis

An in vitro characterisation of the Trichomonas vaginalis TATA box-binding proteins (TBPs)

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