RESUMO
Toxoplasma gondii is an obligate intracellular apicomplexan that causes toxoplasmosis in humans and animals. Central to its dissemination and pathogenicity is the ability to rapidly divide in the tachyzoite stage and infect any type of nucleated cell. Adaptation to different cell contexts requires high plasticity in which heat shock proteins (Hsps) could play a fundamental role. Tgj1 is a type I Hsp40 of T. gondii, an ortholog of the DNAJA1 group, which is essential during the tachyzoite lytic cycle. Tgj1 consists of a J-domain, ZFD, and DNAJ_C domains with a CRQQ C-terminal motif, which is usually prone to lipidation. Tgj1 presented a mostly cytosolic subcellular localization overlapping partially with endoplasmic reticulum. Protein-protein Interaction (PPI) analysis showed that Tgj1 could be implicated in various biological pathways, mainly translation, protein folding, energy metabolism, membrane transport and protein translocation, invasion/pathogenesis, cell signaling, chromatin and transcription regulation, and cell redox homeostasis among others. The combination of Tgj1 and Hsp90 PPIs retrieved only 70 interactors linked to the Tgj1-Hsp90 axis, suggesting that Tgj1 would present specific functions in addition to those of the Hsp70/Hsp90 cycle, standing out invasion/pathogenesis, cell shape motility, and energy pathway. Within the Hsp70/Hsp90 cycle, translation-associated pathways, cell redox homeostasis, and protein folding were highly enriched in the Tgj1-Hsp90 axis. In conclusion, Tgj1 would interact with a wide range of proteins from different biological pathways, which could suggest a relevant role in them.
RESUMO
Protozoan parasites have tremendously diverse lifestyles that require adaptation to a remarkable assortment of different environmental conditions. In order to complete their life cycles, protozoan parasites rely on fine-tuning gene expression. In general, protozoa use novel regulatory elements, transcription factors, and epigenetic mechanisms to regulate their transcriptomes. One of the most surprising findings includes the nature of their histones--these primitive eukaryotes lack some histones yet harbor novel histone variants of unknown function. In this review, we describe the histone components of different protozoan parasites based on literature and database searching. We summarize the key discoveries regarding histones and histone variants and their impact on chromatin regulation in protozoan parasites. In addition, we list histone genes IDs, sequences, and genomic localization of several protozoan parasites and Microsporidia histones, obtained from a thorough search of genome databases. We then compare these findings with those observed in higher eukaryotes, allowing us to highlight some novel aspects of epigenetic regulation in protists and to propose questions to be addressed in the upcoming years.
Assuntos
Histonas/genética , Histonas/metabolismo , Parasitos/genética , Parasitos/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Sequência de Aminoácidos , Animais , Núcleo Celular/genética , Núcleo Celular/metabolismo , Regulação da Expressão Gênica , Variação Genética , Genoma de Protozoário , Humanos , Dados de Sequência Molecular , Nucleossomos/genética , Nucleossomos/metabolismo , Parasitos/patogenicidade , Processamento de Proteína Pós-Traducional , Homologia de Sequência de AminoácidosRESUMO
The results of this study describe the immunostimulatory properties of Leishmania infantum Hsp83 (83) to elicit humoral and cellular response against the Toxoplasma gondii Rop2 protein in an adjuvant-free vaccination system. The analysis was performed by immunizing three different mice strains (BALB/c, C57BL/6 and C3H). Mice immunized with fusion Rop2-83 elicited a stronger humoral and cellular response in comparison to mice immunized with Rop2 alone, or a mix of LiHsp83 and Rop2. The fusion protein induced a Th1 type response, with predominance of specific IgG2a/IgG2c isotype and IFN-gamma secretions, whereas Rop2 alone or mixed with LiHsp83 produced a Th1/Th2 mixed response. Vaccination with fusion protein conferred a remarkable resistance against oral infection with ME49 cysts in C57BL/6 and C3H mice, in comparison to mice immunized with Rop2 alone or the protein mixture. Following lethal challenge, a significant survival rate was observed in Rop2-83 immunized Balb/c and C57BL/6 mice in comparison to control groups.
Assuntos
Antígenos de Protozoários/administração & dosagem , Proteínas de Choque Térmico/imunologia , Proteínas de Membrana/imunologia , Proteínas de Protozoários/imunologia , Toxoplasma/imunologia , Animais , Anticorpos Antiprotozoários/biossíntese , Proteínas de Choque Térmico/administração & dosagem , Imunidade Celular , Leishmania infantum/imunologia , Proteínas de Membrana/administração & dosagem , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Proteínas de Protozoários/administração & dosagem , Vacinas Protozoárias/administração & dosagem , Proteínas Recombinantes de Fusão/administração & dosagem , Proteínas Recombinantes de Fusão/imunologia , Toxoplasmose/imunologia , Toxoplasmose/prevenção & controle , Vacinas Sintéticas/administração & dosagemRESUMO
A rapid and simple technique for the purification of Toxoplasma gondii tachyzoites was developed. Highly purified parasites were obtained from the peritoneal exudates of infected mice by means of two consecutive discontinous sucrose gradients run at low speed (10,000xg, 30 min). Parasites obtained by this method conserved its biological activity. Hybridizations tudies with DNA from healthy mice and from purified tachyzoites preparations demonstrated that Toxoplasma gondii tachyzoites DNA could be obtained with better than 90 per cents purity. Preliminary studies with DNA endonucleases showed the presence in the tachyzoites genome of highly repetitives sequences
