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Transcription regulation by CarD in mycobacteria is guided by basal promoter kinetics.
Zhu, Dennis X; Stallings, Christina L.
Afiliação
  • Zhu DX; Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St Louis, Missouri, USA.
  • Stallings CL; Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St Louis, Missouri, USA. Electronic address: stallings@wustl.edu.
J Biol Chem ; 299(6): 104724, 2023 06.
Article em En | MEDLINE | ID: mdl-37075846
ABSTRACT
Bacterial pathogens like Mycobacterium tuberculosis (Mtb) employ transcription factors to adapt their physiology to the diverse environments within their host. CarD is a conserved bacterial transcription factor that is essential for viability in Mtb. Unlike classical transcription factors that recognize promoters by binding to specific DNA sequence motifs, CarD binds directly to the RNA polymerase to stabilize the open complex intermediate (RPo) during transcription initiation. We previously showed using RNA-sequencing that CarD is capable of both activating and repressing transcription in vivo. However, it is unknown how CarD achieves promoter-specific regulatory outcomes in Mtb despite binding indiscriminate of DNA sequence. We propose a model where CarD's regulatory outcome depends on the promoter's basal RPo stability and test this model using in vitro transcription from a panel of promoters with varying levels of RPo stability. We show that CarD directly activates full-length transcript production from the Mtb ribosomal RNA promoter rrnAP3 (AP3) and that the degree of transcription activation by CarD is negatively correlated with RPo stability. Using targeted mutations in the extended -10 and discriminator region of AP3, we show that CarD directly represses transcription from promoters that form relatively stable RPo. DNA supercoiling also influenced RPo stability and affected the direction of CarD regulation, indicating that the outcome of CarD activity can be regulated by factors beyond promoter sequence. Our results provide experimental evidence for how RNA polymerase-binding transcription factors like CarD can exert specific regulatory outcomes based on the kinetic properties of a promoter.
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Texto completo: 1 Coleções: 01-internacional Contexto em Saúde: 3_ND Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Mycobacterium tuberculosis Tipo de estudo: Prognostic_studies Idioma: En Revista: J Biol Chem Ano de publicação: 2023 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Contexto em Saúde: 3_ND Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Mycobacterium tuberculosis Tipo de estudo: Prognostic_studies Idioma: En Revista: J Biol Chem Ano de publicação: 2023 Tipo de documento: Article