GrgA overexpression inhibits Chlamydia trachomatis growth through sigma66- and sigma28-dependent mechanisms
The obligate intracellular bacterium Chlamydia trachomatis is an important human pathogen with a biphasic developmental cycle comprised of an infectious elementary body (EB) and a replicative reticulate body (RB). Whereas σ66, the primary sigma factor, is necessary for transcription of most chlamydi...
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Veröffentlicht in: | Microbial pathogenesis 2021-07, Vol.156, p.104917-104917, Article 104917 |
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Sprache: | eng |
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Zusammenfassung: | The obligate intracellular bacterium Chlamydia trachomatis is an important human pathogen with a biphasic developmental cycle comprised of an infectious elementary body (EB) and a replicative reticulate body (RB). Whereas σ66, the primary sigma factor, is necessary for transcription of most chlamydial genes throughout the developmental cycle, σ28 is required for expression of some late genes. We previously showed that the Chlamydia-specific transcription factor GrgA physically interacts with both of these sigma factors and activates transcription from σ66- and σ28-dependent promoters in vitro. Here, we investigated the organismal functions of GrgA. We show that overexpression of GrgA slows EB-to-RB conversion, decreases RB proliferation, and reduces progeny EB production. In contrast, overexpression of a GrgA variant without the σ28-binding domain shows significantly less severe inhibitory effects, while overexpression of a variant without the σ66-binding domain demonstrates no adverse effects. These findings indicate that GrgA plays important roles in the expression regulation of both σ66-dependent genes and σ28-dependent genes during the chlamydial developmental cycle.
•A novel Chlamydia-specific transcription factor is important for chlamydial growth.•This novel transcription factor termed GrgA regulates early development.•GrgA also regulates midcycle replication.•GrgA regulates transcription by binding parts of the RNA polymerase. |
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ISSN: | 0882-4010 1096-1208 1096-1208 |
DOI: | 10.1016/j.micpath.2021.104917 |