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| C. Ciências Biológicas - 8. Genética - 2. Genética de Microorganismos | ||
| ASSESSING INTRAFLAGELLAR TRANSPORT PROTEINS OF Leishmania spp. THROUGH in silico ANALYSIS | ||
| João José de Simoni Gouveia 1, 2 (jjsg@secrel.com.br), Elton José Rosas de Vasconcelos 1, 2, Marianna Colares Albuquerque 1, 2, Allan Rodrigo Soares Maia 1, Thiago Dias Ferreira 1, Daniel Costa Fortier 1, Ana Carolina Landim Pacheco 1, Raimundo Bezerra da Costa 1, 2, Rodrigo Maggioni 1, 3 e Diana Magalhães de Oliveira 1, 2 | ||
| (1. Núcleo de Genômica e Bioinformática, Faculdade de Veterinária, Universidade Estadual do Ceará; 2. Faculdade de Veterinária - FAVET, Universidade Estadual do Ceará - UECE; 3. Faculdade de Ciências e Letras do Sertão Central – FECLESC, UECE) | ||
| INTRODUÇÃO:
Leishmania spp. are obligate intracellular pathogens that exist in two forms: a promastigote form (elongated cells with a long flagellum) that converts into amastigote (ovoid cells exhibiting a very short flagellum). The flagellum is, then, a surface organelle that plays a key role in Leishmania motility and sensory reception, and it is essential for parasite migration, invasion and persistence on host tissues. The flagellum is the classical motility organelle that moves the parasite forward by wave-like beats of the microtubule-based flagellar axoneme, but it is also involved in additional biological activities such as the early interaction with the hosts. The contribution of pathogen locomotion/movement to virulence is well documented for bacterial and viral pathogens. Regarding trypanosomatid protozoa, e.g., Leishmania spp., the contribution of cell motility to host-pathogen interactions has been largely unexplored, although there are significant evidences of roles for the flagellum in the control of cell size, shape, polarity and division (cytokinesis). Flagella are constructed and maintained through the highly conserved process of intraflagellar transport (IFT), for which many of the proteins involved have yet to be identified in trypanosomatids. |
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| METODOLOGIA:
The underlying sequencing projects of whole genome shotgun strategies on L. major, L. infantum and L. braziliensis (ftp://ftp.sanger.ac.uk) and its proteomic analysis (http://www.cri.crchul.ulaval.ca/proteome), plus our own L. chagasi EST strategy (http://nugen.lcc.uece.br/leishmaniaLogin.php), with all publicly available datasets on Leishmania spp (NCBI; EBI, GeneDB; PIR; PDB; Structural Genomics of Pathogenic Protozoa at http://sgpp.org) were used as main sources for nucleotide and amino acid sequences, as well as data from other trypanosomatids (T. cruzi at http://tcruzidb.org; T. brucei and T. gambiensi), other eukaryotes (Chlamydomonas reinhardtii, Plasmodium falciparum, Caenorhabditis elegans, Aspergillus fumigatus and Schistosoma mansoni), and prokaryotic genomes (Shigella flexneri, Coxiella burnetti and Vibrio cholerae). Genefinder, GLIMMER 2.0, GlimmerM and GENESCAN were employed to identify candidate genes through database searches and gene prediction methods, while for global analysis and 3D modeling of protein sequences, we used MUSCLE (Edgar, 2004), the STING Millenium suite (Higa et al., 2004) and Modeller (Sali and Blundell, 1993). These open-source softwares facilitate instant access to relevant genomic information, providing comparing multiple sequences to assess correlations and relationships. |
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| RESULTADOS:
In an attempt to better characterize the pathogenic role of flagellum in Leishmania infection, we have performed a detailed sequence and structural analysis of several Leishmania flagellar proteins such as: profilin (an actin polymerization protein that also binds to polyphosphoinositides such as PIP2), kinesin and cytoplasmic dynein heavy chain (respectively the anterograde and retrograde components of IFT), katanin (a microtubule-severing ATPase), coronin (a WD-repeat actin-binding protein) and the putative IFT20 and IFT88 (two components of the IFT complex, composed of at least 15 different polypeptides in Chlamydomonas), among other possible actin-related proteins (ARPs). Most of these flagellar proteins of Leishmania spp. have a common feature of actin-binding or actin-interacting activity and they might be involved in flagellar remodeling. We present results here that underscore original findings in Leishmania genome and proteome profiles in terms of some apparently contradictory flagellar features (motility versus stability, structural conservation/simplicity versus functional dynamics/complexity). |
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| CONCLUSÕES:
Our in silico examinations of the predicted actin-related sequences, reported here, lead us to the assumption of a flagellar remodeling hypothesis that might link the promastigote form of Leishmania (highly dividing and infective) with a presumably nuclear migration and genomic union scenario: dynamic events that can be part of a persistent flagellar remodeling pace exhibited by this protozoa, while establishing a successful infection. We also expect to help in the secondary annotation of Leishmania gene products, improving the bioinformatics contribution on the study of members of this important genus of pathogens. |
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| Instituição de fomento: FUNCAP, CNPq, FINEP, BNB/FUNDECI | ||
| Trabalho de Iniciação Científica | ||
| Palavras-chave: intraflagellar proteins; Leishmania; in silico. | ||
| Anais da 57ª Reunião Anual da SBPC - Fortaleza, CE - Julho/2005 |