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bioRxiv · 10.1101/322701

A role for GrgA in regulation of σ28-dependent transcription in the obligate intracellular bacterial pathogen Chlamydia trachomatis

Desai, M.·Wurihan, W.·Di, R.·Fondell, J. D.·Nickels, B.·Bao, X.·Fan, H.
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Abstract

The sexually transmitted obligate intracellular bacterial pathogen Chlamydia trachomatis has a unique developmental cycle consisting of two contrasting cellular forms. Whereas the primary Chlamydia sigma factor, {sigma}66, is involved in the expression of the majority of chlamydial genes throughout the developmental cycle, expression of several late genes requires the alternative sigma factor {sigma}28. In prior work we identified GrgA as a Chlamydia-specific transcription factor that activates {sigma}66-dependent transcription by binding DNA and interacting with a non-conserved region (NCR) of {sigma}66. Here, we extend these findings by showing GrgA can also activate {sigma}28-dependent transcription through direct interaction with {sigma}28. We measure the binding affinity of GrgA for both {sigma}66and {sigma}28, and we identify regions of GrgA important for {sigma}28-dependent transcription. Similar to results obtained with {sigma}66, we find that GrgAs interaction with {sigma}28 involves a NCR located upstream of conserved region 2 of {sigma}28. Our findings suggest GrgA is an important regulator of both {sigma}66- and {sigma}28-dependent transcription in C. trachomatis and further highlight NCRs of bacterial RNA polymerase as targets for regulatory factors unique to particular organisms.

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Desai, M., Wurihan, W., Di, R., Fondell, J. D., Nickels, B., Bao, X., Fan, H.. 2018-05-15. A role for GrgA in regulation of σ28-dependent transcription in the obligate intracellular bacterial pathogen Chlamydia trachomatis. https://doi.org/10.1101/322701

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