Biology subjects

Foerstner, K. U.

Publications and source records attributed to Foerstner, K. U..

6 recordsLinked to original sources

bioRxiv2025

Early posttranscriptional response to tetracycline exposure in a gram-negative soil bacterium reveals unexpected attenuation mechanism of a DUF1127 gene

The Gram-negative, soil-dwelling plant symbiont Sinorhizobium meliloti shares its free-living habitat with antibiotic producers. To learn about early steps of its adaptation to antibiotics, we analyzed transcriptome changes after 10 min exposure to subinhibitory amount of tetracycline (Tc). RNA-seq revealed 297 differentially expressed genes. Besides ten upregulated ribosomal genes, there was no recognizable functional pattern in the observed changes. Instead, upregulated genes were mostly first in operons and often small, while downregulated genes were downstream in operons. Furthermore, we detected mRNA stabilization upon Tc exposure for several up- and down-regulated genes. Thus, mRNA stabilization contributed to increased mRNA levels, but for downstream genes its effect was counteracted by premature transcriptional termination caused by disrupted coupling between transcription and translation. Using reporter constructs, we found that a DUF1127 gene, showing highest mRNA increase, is controlled by transcription attenuation depending on the translation of an upstream ORF (uORF). Our data suggest the following model: The attenuation strongly depends on the accessibility of C-rich codons at the begin of the uORF. The accessibility is guaranteed by translation of the uORF, and is possible in a time window after a ribosome moves downstream and before a next ribosome occupies the ribosomal binding site (RBS). The accessibility is blocked either by impaired translation initiation or, in the absence of ribosome binding, by base-pairing between the RBS and the C-rich codons. We propose that this is used by bacteria to monitor ribosome availability and translation efficiency, and to ensure reciprocal expression of the DUF1127 gene.

molecular biology↗

bioRxiv2022

READemption 2: Multi-species RNA-Seq made easy

Dual or Multi RNA-seq simultaneously analyze the transcriptomes of two or more interacting species to gain insights about their interplay. The RNA of the interacting species is collected and sequenced together and only separated in silico by mapping the reads to the corresponding genomes. We developed READemption 2.0, to our knowledge the first tool that performs all necessary steps to handle RNA-seq data from any number of species. These steps comprise basic quality filtering and adapter trimming of raw reads, aligning the reads to reference genomes, generating nucleotide-wise coverage files, creating gene-wise read counts and performing differential gene expression analysis. These results can be visualized by additional subcommands of the software. READemption 2.0 allows users to produce meaningful results with default settings that follow conventional standards. Furthermore, many parameters can be adjusted to meet the users specific needs, e.g. keeping or discarding species cross-mapped reads or normalizing the data.

bioinformatics↗

bioRxiv2020

CoxBase: an online platform for epidemiological surveillance, visualization, analysis and typing of Coxiella burnetii genomic sequence

Q (query) fever is an infectious zoonotic disease caused by the Gram-negative bacteria Coxiella burnetii. Although the disease has been studied since decades, it still represents a threat due to sporadic outbreaks across farms in Europe. The absence of a central platform for Coxiella typing data management in an important epidemiological gap which is relevant in the case of an outbreak. To fill this gap, we have designed and implemented an online, open-source, and, web-based platform called CoxBase (https://coxbase.q-gaps.de). This platform includes a database that holds genotyping information of more than 400 Coxiella isolates alongside metadata that annotates them. We have also implemented features for in silico genotyping of completely or minimally assembled Coxiella sequences using five different typing methods, querying existing isolates, visualization of isolates geodata via aggregation on a world map and submission of new isolates. We tested our in silico typing method on 50 Coxiella genomes downloaded from the RefSeq database and we successfully genotyped all except for cases where the sequence quality was poor. We identified new spacer sequences using our implementation of the MST in silico typing method, and established adaA gene phenotypes for all 50 genomes as well as their plasmid types.

bioinformatics↗

bioRxiv2019

YBEY is an essential biogenesis factor for mitochondrial ribosomes

Ribosome biogenesis requires numerous trans-acting factors, some of which are deeply conserved. In Bacteria, the endoribonuclease YbeY is believed to be involved in 16S rRNA 3-end processing and its loss was associated with ribosomal abnormalities. In Eukarya, YBEY appears to generally localize to mitochondria (or chloroplasts). Here we show that the deletion of human YBEY results in a severe respiratory deficiency and morphologically abnormal mitochondria as an apparent consequence of impaired mitochondrial translation. Reduced stability of 12S rRNA and the deficiency of several proteins of the small ribosomal subunit in YBEY knockout cells pointed towards a defect in mitochondrial ribosome biogenesis. The specific interaction of mitoribosomal protein uS11m with YBEY suggests that the latter recruits uS11m to the nascent small subunit in its late assembly stage. This scenario shows similarities with final stages of cytosolic ribosome biogenesis, and may represent a late checkpoint before the mitoribosome engages in translation.

molecular biology↗

bioRxiv2019

Posttranscriptional regulation of ribosomal and multiresistance genes by the bacterial leader peptide peTrpL

The ribosome-dependent attenuator located upstream of bacterial tryptophan biosynthesis genes harbors a small ORF trpL containing tryptophan codons. When tryptophan is available, efficient trpL translation causes transcription termination and release of the attenuator RNA rnTrpL. In Sinorhizobium meliloti, rnTrpL is a trans-acting sRNA. Here, we identified an evolutionary conserved function for the trpL-encoded 14-aa leader peptide peTrpL. Upon exposure to tetracycline, the cellular peTrpL levels were increased and rnTrpL was generated independently of tryptophan availability. Both peTrpL and rnTrpL were found to be involved in tetracycline-dependent destabilization of rplUrpmA mRNA encoding ribosomal proteins L21 and L27. We provide evidence for redirection of the sRNA rnTrpL from its antibiotic-independent target trpDC to rplUrpmA by formation of an antibiotic-dependent ribonucleoprotein complex (ARNP). ARNPs comprising peTrpL, rnTrpL, rplUrpmA and antisense RNA were also observed for other translation-inhibiting antibiotics, suggesting that bacteria evolved mechanisms to utilize antibiotics for mRNA destabilization.

microbiology↗

bioRxiv2017

ANNOgesic: A Pipeline To Translate Bacterial/Archaeal RNA-Seq Data Into High-Resolution Genome Annotations

To understand the gene regulation of an organism of interest, a comprehensive genome annotation is essential. While some features, such as coding sequences, can be computationally predicted with high accuracy based purely on the genomic sequence, others, such as promoter elements or non-coding RNAs are harder to detect. RNA-Seq has proven to be an efficient method to identify these genomic features and to improve genome annotations. However, processing and integrating RNA-Seq data in order to generate high-resolution annotations is challenging, time consuming and requires numerous different steps. We have constructed a powerful and modular tool called ANNOgesic that provides the required analyses and simplifies RNA-Seq-based bacterial and archaeal genome annotation. It can integrate data from conventional RNA-Seq and dRNA-Seq, predicts and annotates numerous features, including small non-coding RNAs, with high precision. The software is available under an open source license (ISCL) at https://pypi.org/project/ANNOgesic/.

bioinformatics↗