Publicação
Characterization of two newly identified Chlamydia trachomatis inclusion membrane proteins
| Resumo: | Chlamydia trachomatis is a human pathogen that causes genital and ocular infections worldwide. It is an obligate intracellular bacterium that alternates between an infectious (EB, elementary body) and a replicative (RB, reticulate body) form during an infectious cycle in which chlamydiae localizes inside a membrane-bound vacuole known as an inclusion. To manipulate host cell processes from within the inclusion, C. trachomatis delivers several effector proteins into the host cell through a type III secretion system. Some of these effectors, known as Incs, possess hydrophobic domains enabling their insertion into the inclusion membrane. Some Incs localize at specific regions of the inclusion membrane, termed microdomains. We previously identified C. trachomatis CT195 and CT214 as two putative Incs. To test if they are bona fide Incs, in this work, we first analyzed their subcellular localization in infected cells by immunofluorescence microscopy. This revealed that they localized in the inclusion membrane in all time points assessed, i.e., they are bona fide Incs, and that CT214 also localized in microdomains at the inclusion membrane. Furthermore, we generated and characterized a C. trachomatis ct195 mutant strain. By comparing cells infected by CT195-producing (parental and complemented strains) or CT195- deficient C. trachomatis, we showed that CT195 reduced the chlamydial intracellular growth and delayed the homotypic fusion between inclusions. This suggests that CT195 regulates chlamydial growth; however, the underlying mechanism and relevance of this role of CT195 are presently unknown. We also showed that CT195, like other Incs, contributes to induce multinucleation in infected cells, indicating that it is involved in the known ability of C. trachomatis to inhibit host cell cytokinesis. Overall, this work allowed to increase the current knowledge on Incs, a family of important C. trachomatis virulence proteins. |
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| Autores principais: | Bispo, Andreia dos Reis |
| Assunto: | Chlamydia trachomatis effectors Inc proteins membrane microdomains cytokinesis |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | Chlamydia trachomatis is a human pathogen that causes genital and ocular infections worldwide. It is an obligate intracellular bacterium that alternates between an infectious (EB, elementary body) and a replicative (RB, reticulate body) form during an infectious cycle in which chlamydiae localizes inside a membrane-bound vacuole known as an inclusion. To manipulate host cell processes from within the inclusion, C. trachomatis delivers several effector proteins into the host cell through a type III secretion system. Some of these effectors, known as Incs, possess hydrophobic domains enabling their insertion into the inclusion membrane. Some Incs localize at specific regions of the inclusion membrane, termed microdomains. We previously identified C. trachomatis CT195 and CT214 as two putative Incs. To test if they are bona fide Incs, in this work, we first analyzed their subcellular localization in infected cells by immunofluorescence microscopy. This revealed that they localized in the inclusion membrane in all time points assessed, i.e., they are bona fide Incs, and that CT214 also localized in microdomains at the inclusion membrane. Furthermore, we generated and characterized a C. trachomatis ct195 mutant strain. By comparing cells infected by CT195-producing (parental and complemented strains) or CT195- deficient C. trachomatis, we showed that CT195 reduced the chlamydial intracellular growth and delayed the homotypic fusion between inclusions. This suggests that CT195 regulates chlamydial growth; however, the underlying mechanism and relevance of this role of CT195 are presently unknown. We also showed that CT195, like other Incs, contributes to induce multinucleation in infected cells, indicating that it is involved in the known ability of C. trachomatis to inhibit host cell cytokinesis. Overall, this work allowed to increase the current knowledge on Incs, a family of important C. trachomatis virulence proteins. |
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