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Genetic code expansion enables visualization of Salmonella type three secretion system components and secreted effectors.

ABSTRACT: Type three secretion systems enable bacterial pathogens to inject effectors into the cytosol of eukaryotic hosts to reprogram cellular functions. It is technically challenging to label effectors and the secretion machinery without disrupting their structure/function. Herein, we present a new approach for labeling and visualization of previously intractable targets. Using genetic code expansion, we site-specifically labeled SsaP, the substrate specificity switch, and SifA, a here-to-fore unlabeled secreted effector. SsaP was secreted at later infection times; SsaP labeling demonstrated the stochasticity of injectisome and effector expression. SifA was labeled after secretion into host cells via fluorescent unnatural amino acids or non-fluorescent labels and a subsequent click reaction. We demonstrate the superiority of imaging after genetic code expansion compared to small molecule tags. It provides an alternative for labeling proteins that do not tolerate N- or C-terminal tags or fluorophores and thus is widely applicable to other secreted effectors and small proteins.

SUBMITTER: Singh MK

PROVIDER: S-EPMC8192122 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Systematic analysis of the regulation of type three secreted effectors in Salmonella enterica serovar Typhimurium.

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Genetic code expansion in stable cell lines enables encoded chromatin modification

Project description:Genetically encoded unnatural amino acids provide powerful strategies for modulating the molecular functions of proteins in mammalian cells. However this approach has not been coupled to genome-wide measurements, because efficient unnatural amino acid incorporation is limited to readily transfectable cells and leads to very heterogeneous expression. We demonstrate that rapid piggybac integration of the orthogonal pyrrolysyl-tRNA synthetase (PylS)/tRNAPyl CUA pair (and its derivatives) into the mammalian genome enables efficient, homogeneous unnatural amino acid incorporation into target proteins in diverse cells, and we reveal the distinct transcriptional responses of ES cells and MEFs to amber suppression. Genetically encoding NÎµ-acetyl-lysine in place of six lysine residues in histone H3, that are known to be post-translationally acetylated, enables deposition of pre-acetylated histones into cellular chromatin, via a synthetic pathway that is orthogonal to enzymatic modification, allowing us to determine the consequences of acetylation at specific amino acids in histones on gene expression. mRNA was sequenced using polyA-enrichment and Truseq library preparation protocol. Two biological replicates were sequences for each cell line and condition

2016-07-03 | E-GEOD-73823 | biostudies-arrayexpress

Genetic code expansion in stable cell lines enables encoded chromatin modification.

Project description:Genetically encoded unnatural amino acids provide powerful strategies for modulating the molecular functions of proteins in mammalian cells. However, this approach has not been coupled to genome-wide measurements, because efficient incorporation of unnatural amino acids is limited to transient expression settings that lead to very heterogeneous expression. We demonstrate that stable integration of the Methanosarcina mazei pyrrolysyl-tRNA synthetase (PylRS)/tRNA(Pyl)CUA pair (and its derivatives) into the mammalian genome enables efficient, homogeneous incorporation of unnatural amino acids into target proteins in diverse mammalian cells, and we reveal the distinct transcriptional responses of embryonic stem cells and mouse embryonic fibroblasts to amber codon suppression. Genetically encoding N-?-acetyl-lysine in place of six lysine residues in histone H3 enables deposition of pre-acetylated histones into cellular chromatin, via a pathway that is orthogonal to enzymatic modification. After synthetically encoding lysine-acetylation at natural modification sites, we determined the consequences of acetylation at specific amino acids in histones for gene expression.

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Project description:Identification of mouse proteins targeted by Salmonella secreted effectors by affinity purification followed by mass spectrometry.

2020-04-03 | PXD004002 | Pride

Diverse secreted effectors are required for Salmonella persistence in a mouse infection model.

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Genetic code expansion in stable cell lines enables encoded chromatin modification

Project description:Genetically encoded unnatural amino acids provide powerful strategies for modulating the molecular functions of proteins in mammalian cells. However this approach has not been coupled to genome-wide measurements, because efficient unnatural amino acid incorporation is limited to readily transfectable cells and leads to very heterogeneous expression. We demonstrate that rapid piggybac integration of the orthogonal pyrrolysyl-tRNA synthetase (PylS)/tRNAPyl CUA pair (and its derivatives) into the mammalian genome enables efficient, homogeneous unnatural amino acid incorporation into target proteins in diverse cells, and we reveal the distinct transcriptional responses of ES cells and MEFs to amber suppression. Genetically encoding Nε-acetyl-lysine in place of six lysine residues in histone H3, that are known to be post-translationally acetylated, enables deposition of pre-acetylated histones into cellular chromatin, via a synthetic pathway that is orthogonal to enzymatic modification, allowing us to determine the consequences of acetylation at specific amino acids in histones on gene expression.

2016-01-01 | GSE73823 | GEO

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