Escherichia coli
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA919078 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR23003430.fastq.gz | Fastqsanger.gz | |||
| SRR23003431.fastq.gz | Fastqsanger.gz | |||
| SRR23003432.fastq.gz | Fastqsanger.gz | |||
| SRR23003433.fastq.gz | Fastqsanger.gz | |||
| SRR23003434.fastq.gz | Fastqsanger.gz |
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Project description:We present LoxTnSeq, a new methodology to generate and catalogue libraries of genome reduction mutants. LoxTnSeq combines random integration of Lox sites by transposon mutagenesis, and the generation of mutants via cre recombinase, catalogued via deep-sequencing. When LoxTnSeq was applied to the naturally genome reduced bacterium Mycoplasma pneumoniae, we obtained a mutant pool containing 285 unique deletions. These deletions spanned from >50 bp to 28 Kb, which represent 21% of the total genome. LoxTnSeq also highlighted large regions of non-essential genes that could be removed simultaneously, and other similar regions that could not, providing a guide for future genome reductions.
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Project description:The yeast Saccharomyces cerevisiae is a highly powerful model for systems genetics. While the advent of ordered deletion libraries has considerably facilitated yeast screening, it has also narrowed the diversity of screenable variants and precluded the exploration of the non-coding genome. Here, we present a versatile, time- and work-efficient method to functionally explore the yeast genome at an unprecedented throughput and resolution, using saturated transposon mutagenesis coupled to high-throughput sequencing. SAturated Transposon Analysis in Yeast (SATAY) allows the one-step mapping of all genetic loci in which a transposon can be inserted without disrupting a function necessary for cell growth. SATAY is especially suited to discover loci important for growth in various conditions. Here, we demonstrate that SATAY can be used to (2) reveal genetic interactions in single and multiple mutant strains, (1) reveal drug-resistant and -sensitive mutants, (3) detect not only essential genes, but also essential functional protein domains, and (4) generate not only null alleles, but also other informative genetic variants. Thus SATAY allows to easily explore the yeast genome at an unprecedented resolution and throughput.
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Project description:This dataset was used to assess the random insertion by tranposases of lox sites in Mycoplasma pneumoniae. This is part of the protocol LoxTnSeq, a new methodology to generate and catalogue libraries of genome reduction mutants. LoxTnSeq combines random integration of Lox sites by transposon mutagenesis, and the generation of mutants via cre recombinase, catalogued via deep-sequencing. When LoxTnSeq was applied to the naturally genome reduced bacterium Mycoplasma pneumoniae, we obtained a mutant pool containing 285 unique deletions. These deletions spanned from >50 bp to 28 Kb, which represent 21% of the total genome. LoxTnSeq also highlighted large regions of non-essential genes that could be removed simultaneously, and other similar regions that could not, providing a guide for future genome reductions.
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Project description:TnpB nucleases represent the evolutionary precursors to CRISPR-Cas12 and are widespread in all domains of life. IS605-family TnpB homologs function in bacteria as programmable RNA-guided homing endonucleases driving transposon maintenance through DSB-stimulated homologous recombination. Here we uncover molecular mechanisms of transposition lifecycle of IS607-family elements that, remarkably, also encode group I introns. We discover molecular features for a candidate ‘IStron’ from Clostridium botulinum that allow the element to carefully control the relative levels of spliced products versus functional guide RNAs. Our results suggest that IStron transcripts have evolved a sensitive equilibrium to balance competing and mutually exclusive activities that promote transposon maintenance while limiting adverse fitness costs on the host. Collectively, this work highlights molecular innovation in the multi-functional utility of transposon-encoded noncoding RNAs.
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Project description:Targeted transposon screening in bacteria by CRISPR/Cas12k-guided transposase
| PRJNA691969 | ENA
Project description:Key to CRISPR-Cas adaptive immunity is maintaining an ongoing record of invading nucleic acids that are encountered, a process carried out by the Cas1-Cas2 complex that integrates short segments of foreign genetic material (spacers) into the CRISPR locus. It is hypothesized that Cas1 evolved from casposases, a novel class of transposases. We show here that casposase integration in vitro recapitulates several properties of CRISPR-Cas integrases. The X-ray structure of Methanosarcina mazei casposase bound to DNA representing the product of integration reveals a tetramer with target DNA bound snugly between two dimers in which single-stranded casposon end binding resembles that of spacer 3'-overhangs. The differences between transposase and CRISPR-Cas integrase are largely architectural, and it appears that evolutionary change involved changes in protein-protein interactions to favor Cas2 binding over tetramerization and the separation of Cas1 dimers. This, in turn, led to preferred integration of single spacers over two transposon ends.
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