Publications by authors named "Jarmila Hnilicova"

In mycobacteria, σ is the primary sigma factor. This essential protein binds to RNA polymerase (RNAP) and mediates transcription initiation of housekeeping genes. Our knowledge about this factor in mycobacteria is limited.

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Unlabelled: is an emerging opportunistic pathogen affecting patients with chronic lung diseases, primarily cystic fibrosis (CF), or those under immunosuppression. Hence, investigations into the epidemiology and transmission of and accurate antibiotic susceptibility data are essential for the effective treatment of infections caused by this pathogen. This retrospective nationwide study included all clinical isolates ( = 59) from 29 patients diagnosed in the Czech Republic and Slovakia between 2018 and 2023.

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Bacteria have evolved structured RNAs that can associate with RNA polymerase (RNAP). Two of them have been known so far-6S RNA and Ms1 RNA but it is unclear if any other types of RNAs binding to RNAP exist in bacteria. To identify all RNAs interacting with RNAP and the primary σ factors, we have established and performed native RIP-seq in Bacillus subtilis, Corynebacterium glutamicum, Streptomyces coelicolor, Mycobacterium smegmatis and the pathogenic Mycobacterium tuberculosis.

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Article Synopsis
  • Rifampicin is an important antibiotic that targets bacterial RNA polymerase, preventing proper transcription by blocking its DNA/RNA channel.
  • HelD proteins help maintain genome integrity by removing stalled RNA polymerases, while HelR proteins from high G+C Actinobacteria can specifically dissociate rifampicin-stalled RNAPs, offering resistance to the antibiotic.
  • The text discusses the role of HelD/HelR in the transcription cycle, explores potential involvement of similar proteins in low G+C Firmicutes in resistance, and emphasizes the implications for understanding bacterial antibiotic resistance mechanisms.
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Bacteria employ small non-coding RNAs (sRNAs) to regulate gene expression. Ms1 is an sRNA that binds to the RNA polymerase (RNAP) core and affects the intracellular level of this essential enzyme. Ms1 is structurally related to 6S RNA that binds to a different form of RNAP, the holoenzyme bearing the primary sigma factor.

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RNA synthesis is central to life, and RNA polymerase (RNAP) depends on accessory factors for recovery from stalled states and adaptation to environmental changes. Here, we investigated the mechanism by which a helicase-like factor HelD recycles RNAP. We report a cryo-EM structure of a complex between the Mycobacterium smegmatis RNAP and HelD.

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Bacterial RNA polymerase (RNAP) is essential for gene expression and as such is a valid drug target. Hence, it is imperative to know its structure and dynamics. Here, we present two as-yet-unreported forms of RNAP: core and holoenzyme containing σ but no other factors.

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Article Synopsis
  • * Its accumulation is due to high synthesis levels and reduced degradation, and key elements have been identified that regulate its promoter activity.
  • * Without Ms1, levels of RNA polymerase subunits decrease, leading to a limited RNA polymerase pool, which hampers the ΔMs1 strain's ability to adapt quickly to environmental changes from stationary phase.
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  • The σ sigma factor is a crucial transcriptional regulator linked to RNA polymerase, playing a significant role in helping bacteria adapt to higher temperatures; this study fully characterizes its functions and effects.
  • Through RNA sequencing, around 130 genes were found to be influenced by the lack of this σ factor; of these, 16 genes are directly regulated by σ, with many related to iron metabolism.
  • The research also examines the specific promoter sequences crucial for σ-dependent transcription, highlighting the sigma factor's complex role in gene expression and potential applications in biotechnology.
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Small RNAs (sRNAs) are molecules essential for a number of regulatory processes in the bacterial cell. Here we characterize Ms1, a sRNA that is highly expressed in Mycobacterium smegmatis during stationary phase of growth. By glycerol gradient ultracentrifugation, RNA binding assay, and RNA co-immunoprecipitation, we show that Ms1 interacts with the RNA polymerase (RNAP) core that is free of the primary sigma factor (σA) or any other σ factor.

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Histone acetylation modulates alternative splicing of several hundred genes. Here, we tested the role of the histone acetyltransferase p300 in alternative splicing and showed that knockdown of p300 promotes inclusion of the fibronectin (FN1) alternative EDB exon. p300 associates with CRE sites in the promoter via the CREB transcription factor.

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Brd2 is a member of the bromodomain extra terminal (BET) protein family, which consists of four chromatin-interacting proteins that regulate gene expression. Each BET protein contains two N-terminal bromodomains, which recognize acetylated histones, and the C-terminal protein-protein interaction domain. Using a genome-wide screen, we identify 1450 genes whose transcription is regulated by Brd2.

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Background: Nuclear myosin I (NM1) was the first molecular motor identified in the cell nucleus. Together with nuclear actin, they participate in crucial nuclear events such as transcription, chromatin movements, and chromatin remodeling. NM1 is an isoform of myosin 1c (Myo1c) that was identified earlier and is known to act in the cytoplasm.

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There are numerous data suggesting that two key steps in gene expression-transcription and splicing influence each other closely. For a long time it was known that chromatin modifications regulate transcription, but only recently it was shown that chromatin and histone modifications play a significant role in pre-mRNA splicing. Here we summarize interactions between splicing machinery and chromatin and discuss their potential functional significance.

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There is increasing evidence to suggest that splicing decisions are largely made when the nascent RNA is still associated with chromatin. Here we demonstrate that activity of histone deacetylases (HDACs) influences splice site selection. Using splicing-sensitive microarrays, we identified ∼700 genes whose splicing was altered after HDAC inhibition.

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Article Synopsis
  • The AD29 mutation in the HPRP31 gene is linked to retinitis pigmentosa type 11, but its exact mechanism of causing the disorder is still unclear.
  • The mutation impacts cell proliferation and disrupts the structure of nuclear Cajal bodies, which play a role in snRNP metabolism, but these effects can be reversed by over-expressing the hPrp6 protein.
  • Evidence shows that the AD29 mutant has reduced stability and interactions with snRNPs, leading to rapid degradation, which could contribute to the RP phenotype by diminishing the function of the hPrp31 protein.
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