RESUMO
Trichomonas vaginalis eIF-5A-like protein (TveIF-5A) belongs to the highly conserved eIF-5A family of proteins that contains a unique polyamine-derived amino acid, hypusine. Recently, we determined that the polyamine putrescine is required for tveif-5a mRNA stability, and it is necessary for stability and maturation of the TveIF-5A protein. Eukaryotic eIF-5A is known to be involved in mRNA turnover and is capable of sequence-specific RNA binding to eIF-5A response elements (EREs). These ERE sequences are present in diverse mammalian mRNAs, including human cyclooxygenase-2 (cox-2). Here, we cloned the complete coding sequence of TveIF-5A and overexpressed it in a eukaryotic system. The recombinant protein (rTveIF-5A) was purified in soluble form using size-exclusion chromatography. Because of the polyamine-dependent regulation of TvCP39 (a protease of T. vaginalis) at the protein and RNA messenger (mRNA) levels, we looked for an ERE-like structure in the 3' region of tvcp39 mRNA. In RNA gel-shift assays, rTveIF-5A bound to transcripts at the EREs of cox-2 or tvcp39 mRNAs. This work shows the eIF-5A/ERE-like interaction in T. vaginalis.
Assuntos
Fatores de Iniciação de Peptídeos/genética , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes/genética , Elementos de Resposta/genética , Trichomonas vaginalis/genética , Animais , Linhagem Celular , Células HeLa , Humanos , Ligação Proteica/genética , Processamento de Proteína Pós-Traducional/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/metabolismo , Proteínas Recombinantes/metabolismo , Fator de Iniciação de Tradução Eucariótico 5ARESUMO
A decoction from roots and rhizomes of Psacalium palladium is used in Mexico for the treatment of tumors and for control of diabetes mellitus, among other ailments. Although hypoglycemic activity has been demonstrated in various experimental models and some compounds have been detected in the roots and rhizomes, such as alkaloids, glycosides and tannins, toxicity studies have not yet been performed. Moreover, since various species taxonomically related to P. palladium have pyrrolizidine alkaloids (hepatotoxic, carcinogenic and mutagenic agents) it is possible that these species also contain potentially toxic substances, which represents a risk for users. The aim of this investigation was study the cytotoxicity of P. palladium on mouse hematopoietic cells and transformed human cells, evaluating the cell proliferation by the technique of sulforhodamine B. An aqueous fraction (AS) reduced population of both types of cells by over 50%; meanwhile the other extracts did not alter cell number. Fraction AP was cytotoxic for DU-145 cells at 10 microg/mL, whereas the remaining extracts acted like cytostatic agents.