The C. burnetii T4SS effector protein AnkG hijacks the 7SK small nuclear riboprotein complex for reprogramming host cell transcription
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ABSTRACT:
PROVIDER: PRJNA769091 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR16218636_1.fastq.gz | Fastqsanger.gz | |||
| SRR16218636_2.fastq.gz | Fastqsanger.gz | |||
| SRR16218637_1.fastq.gz | Fastqsanger.gz | |||
| SRR16218637_2.fastq.gz | Fastqsanger.gz | |||
| SRR16218638_1.fastq.gz | Fastqsanger.gz |
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Project description:In this study, we analyzed the molecular activity of the anti-apoptotic T4SS effector protein AnkG (CBU0781) to understand how C. burnetii manipulates host cell viability. We demonstrate by RNA-immunoprecipitation that AnkG binds to the host cell 7SK snRNA, an important regulator of the positive transcription elongation factor P-TEFb. Consistent with the documented function of released P-TEFb in RNA Pol II pause release, RNA sequencing experiments confirmed AnkG-mediated transcriptional reprogramming and showed that expression of genes involved in apoptosis, trafficking, and transcription is influenced by AnkG.
2021-10-08 | GSE185428 | GEO
Project description:Inhibition of host cell apoptosis is crucial for survival and replication of several intracellular bacterial pathogens. To interfere with apoptotic pathways, some pathogens use specialized secretion systems to inject bacterial effector proteins into the host cell cytosol. One of these pathogens is the obligate intracellular bacterium Coxiella burnetii, the etiological agent of the zoonotic disease Q fever. In this study, we analyzed the molecular activity of the anti-apoptotic T4SS effector protein AnkG (CBU0781) to understand how C. burnetii manipulates host cell viability. We demonstrate by co- and RNA-immunoprecipitation that AnkG binds to the host cell DExD box RNA helicase 21 (DDX21) as well as to the host cell 7SK small nuclear ribonucleoprotein (7SK snRNP) complex, an important regulator of the positive transcription elongation factor b (P-TEFb). The co-immunoprecipitation of AnkG with DDX21 is probably mediated by salt bridges and is independent of AnkG-7SK snRNP binding, and vice versa. It is known that DDX21 facilitates the release of P-TEFb from the 7SK snRNP complex. Consistent with the documented function of released P-TEFb in RNA Pol II pause release, RNA sequencing experiments confirmed AnkG-mediated transcriptional reprogramming and showed that expression of genes involved in apoptosis, trafficking, and transcription are influenced by AnkG. Importantly, DDX21 and P-TEFb are both essential for AnkG-mediated inhibition of host cell apoptosis, emphasizing the significance of the interaction of AnkG with both, the DDX21 protein and the 7SK RNA. In line with a critical function of AnkG in pathogenesis, the AnkG deletion C. burnetii strain was severely affected in its ability to inhibit host cell apoptosis and to generate a replicative C. burnetii-containing vacuole. In conclusion, the interference with the activity of regulatory host cell RNAs mediated by a bacterial effector protein represent a novel mechanism through which C. burnetii modulates host cell transcription, thereby enhancing permissiveness to bacterial infection. Author summary For intracellular replication, Coxiella burnetii depends on a functional type IV secretion system, which is utilized to inject ~150 virulence factors, so called effector proteins, into the host cell cytosol. Activities have only been established for few of them. These effector proteins interfere with vesicular trafficking, autophagy, lipid metabolism, apoptosis, and transcription by binding and manipulating the activity of host cell proteins. Here, we report that the C. burnetii T4SS effector protein AnkG (CBU0781, Q83DF6) binds to the host cell DExD box helicase 21 (DDX21) as well as to several host cell RNAs, including the small regulatory 7SK RNA, which is an important regulator of the positive elongation factor b (pTEFb). AnkG interferes with the function of the 7SK small nuclear ribonucleoprotein (7SK snRNP) complex, leading to significant changes in host cell transcription and ensuring host cell survival. AnkG activity is essential for efficient intracellular replication of C. burnetii and its ability to inhibit apoptosis. In summary, we identified a novel process by which a bacterial effector protein manipulates the host cell for its own benefit.
| S-EPMC8824381 | biostudies-literature
Project description:Coxiella burnetii is the causative agent of human Q fever, which presents with either acute flu-like symptoms or progresses to chronic endocarditis. Alveolar macrophages engulf C. burnetii after human inhalation, and the pathogen transitions through the phagolysosomal maturation pathway to form a parasitophorous vacuole (PV) for intracellular replication. PV generation requires a type IV secretion system (T4SS) that serves as a critical C. burnetii modulator of host cell activity. We previously showed C. burnetii infection activates the antioxidant Nrf2-Keap1 pathway, stabilizing Nrf2, a transcription factor that translocates to the nucleus. Here, we further investigated the role of Nrf2 during C. burnetii infection of human macrophage-like cells and potential important downstream events that influence infection. We show Nrf2 is activated in a T4SS-dependent manner and that inhibition of Nrf2 activity negatively impacts PV formation and C. burnetii replication. Assessment of oxidative stress-related gene expression revealed that nox4, nqo1, sod1, and sod2 expression increase during infection. Nrf2 inhibition also increases levels of the autophagic proteins LC3, p62, and phosphorylated p62, suggesting dysregulated autophagy is deleterious to infection. Additionally, RNA sequencing analysis determined that Nrf2 inhibition has a significant impact on gene expression involving multiple pathways including oxidative stress, the unfolded protein response, and cell survival signaling. Overall, this study advances understanding of Nrf2 importance during C. burnetii infection and the cellular signaling pathways controlled by Nrf2 in response to an intracellular bacterial pathogen.
2024-12-31 | GSE244628 | GEO
Project description:Transcriptional profiling of Coxiella burnetii phase I (RSA 493) submitting either to Cold and Heat shock comparing to control untreated Coxiella burnetii phase I (RSA 493) grown at 35°C.
2011-01-01 | GSE21778 | GEO
Project description:Q fever is a zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium usually found in myeloid cells. The infection is a source of severe obstetrical complications in humans and cattle, and of chronic evolution in pregnant women. As C. burnetii is found in the placenta of aborted foetuses in humans and ruminants, we wondered if it may infect trophoblasts. In this work, we showed that C. burnetii, infected JEG trophoblastic cells without replication and was localized within phagolysosomes. We analyzed gene expression programs induced by C. burnetii in JEG trophoblastic cell line and compared it with transcriptomic program of BeWo trophoblasts in which C. burnetii replicates. These transcriptomic programs induced by C. burnetii in JEG trophoblasts was poor and markedly different from that induced by C. burnetii in BeWo trophoblasts. Hence, the differences in transcriptomic programs may explain the different intracellular fate of C. burnetii in JEG and BeWo cells. Our results suggest that C. burnetii may use trophoblastic cells as a reservoir by interfering with gene expression.
2012-12-07 | GSE30330 | GEO
Project description:Gene expression requires tight coordination of the molecular machineries that mediate transcription and splicing. While the interplay between transcription kinetics and spliceosome fidelity has been investigated before, less is known about mechanisms regulating the assembly of the spliceosomal machinery in response to transcription changes. Here we report an association of the Smn complex, which mediates spliceosomal snRNP biogenesis, with the 7SK complex involved in transcriptional regulation. We found that Smn interacts with the 7SK core components Larp7 and Mepce and specifically associates with 7SK subcomplexes containing hnRNP R. The association between Smn and 7SK complexes is enhanced upon transcriptional inhibition leading to reduced production of snRNPs. Taken together, our findings reveal a functional association of Smn and 7SK complexes that is governed by global changes in transcription. Thus, in addition to its canonical nuclear role in transcriptional regulation, 7SK has cytosolic functions in fine-tuning spliceosome production according to transcriptional demand.
2021-01-26 | PXD021360 | Pride
Project description:Coxiella burnetii, a category B select agent, is endemic worldwide, except New Zealand. It causes annually several outbreaks of the zoonotic disease Q fever predominantly in small ruminants. To date, the lipopolysaccharide (LPS), besides a type IV secretion system (T4SS), is the only defined and characterized virulence determinant of C. burnetii. This surface molecule is used to distinguish between virulent (Ph I) and low-virulent (Ph II) organisms, the latter emerge only after frequent passaging in the laboratory. As an obligate intracellular pathogen, targeted genetic modification is still not a routine and labour intensive procedure. The deeper study of novel determinants is complicated and demands not only advanced techniques for axenic and for cell culture-based cultivation but also novel approaches in the high-resolution mass spectrometry. This work is the first proteomic study comparing. C. burnetii Ph I and Ph II propagated in different axenic media and in cell culture.
2019-10-24 | PXD013224 | Pride
Project description:Coxiella burnetii undergoes a biphasic developmental cycle within its host cell that generates morphologically and physiologically distinct large cell variants (LCV) and small cell variants (SCV). During the lag phase of the C. burnetii growth cycle, non-replicating SCV differentiate into replicating LCV that in turn differentiate back into SCV during stationary phase. Nearly homogeneous SCV are observed in infected Vero cells after extended incubation (21 to 28 days). In the current study, we sought to establish whether C. burnetii developmental transitions in host cells are recapitulated during host cell-free (axenic) growth in first and second generation acidified citrate cysteine media (ACCM-1 and ACCM-2, respectively). We show that ACCM-2 supported developmental transitions and viability. Although ACCM-1 also supported SCV to LCV transition, LCV to SCV transition did not occur after extended incubation (21 days). Instead, C. burnetii exhibited a ghost-like appearance with bacteria containing condensed chromatin but otherwise devoid of cytoplasmic content. This phenotype correlated with a near total loss in viability between 14 and 21 days of cultivation. Transcriptional profiling of C. burnetii following 14 days of incubation revealed elevated expression of oxidative stress genes in ACCM-1 cultivated bacteria. ACCM-2 differs from ACCM-1 by the substitution of methyl-b-cyclodextrin (Mb-CD) for fetal bovine serum. Addition of Mb-CD to ACCM-1 at 7 days post-inoculation rescued C. burnetii viability and lowered expression of oxidative stress genes. Thus, Mb-CD appears to alleviate oxidative stress in ACCM-2 to result in C. burnetii developmental transitions and viability that mimic host cell-cultivated organisms. Axenic cultivation of C. burnetii in ACCM-2 and new methods
2013-12-02 | GSE51135 | GEO
Project description:Genotyping based on genomic comparative hybridization of different isolates of coxiella burnetii compared to NMI reference strain
2011-12-31 | GSE31543 | GEO
Project description:Coxiella burnetii, the agent of Q fever, persists in humans despite specific immune responses: however, its reservoir remains unknown. We detected C. burnetii in adipose tissue from BALB/c and C57/BL6 mice 4 months after infection when no bacteria were found in other tissues. C. burnetii infected cultivated adipocytes, replicated within late phagosomes and induced a transcriptional program that was enriched for the expression of genes associated with inflammatory response, hormonal responses and cytoskeleton.
2014-05-25 | GSE46335 | GEO