Activation of multifarious transcription of an adhesion protein ap65-1 gene by a novel Myb2 protein in the protozoan parasite Trichomonas vaginalis.
Multifarious transcription of the adhesion protein ap65-1 gene in the human pathogen, Trichomonas vaginalis, is critically regulated by the coordination of two similar but opposite oriented DNA regulatory regions, MRE-1/MRE-2r and MRE-2f, both of which are binding sites for multiple Myb-like proteins. In the present study, MRE-1/MRE-2r was demonstrated to be composed of multiple overlapping promoter elements, among which the entire region is required for growth-related ap65-1 transcription, and the 5'-MRE-1 antagonizes the suppressive activity of the 3'-MRE-2r in iron-inducible transcription. The recombinant Myb2 protein derived from a previously identified myb2 gene was demonstrated to recognize distinct sequence contexts in MRE-2r and MRE-2f, whereas Myb2 in the nuclear lysate preferentially binds to MRE-2f to MRE-2r. Iron repletion resulted in persistent repression of the myb2 gene, and temporal activation/deactivation of Myb2 promoter entry, which was also activated by prolonged iron depletion. The hemagglutinintagged Myb2 when overexpressed during iron-depleted conditions facilitated basal and growth-related ap65-1 transcription to a level that was achieved in iron-replete cells, whereas ironinducible ap65-1 transcription was abolished with knockdown of Myb2. These findings demonstrated that Myb2 is involved in activation of growth-related and iron-inducible transcription of the ap65-1 gene, possibly through differential promoter selection in competition with other Myb proteins.
Ong
Shiou-Jeng
SJ
Department of Parasitology, College of Medicine, National Taiwan University, Taipei, Taiwan.
Hsu
Hong-Ming
HM
Liu
Hsing-Wei
HW
Chu
Chien-Hsin
CH
Tai
Jung-Hsiang
JH
D000818:Animals; D001665:Binding Sites; D015815:Cell Adhesion Molecules / Q000502:physiology*; D007501:Iron / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics* / Q000502:physiology*; D050436:Regulatory Elements, Transcriptional; D015534:Trans-Activators / Q000502:physiology*; D015533:Transcriptional Activation; D014246:Trichomonas vaginalis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
C096723:AP65-1 protein, Trichomonas vaginalis; D015815:Cell Adhesion Molecules; C520248:Myb2 protein, Trichomonas vaginalis; D015800:Protozoan Proteins; D015534:Trans-Activators; D007501:Iron