scholarly journals Switchable genome editing via genetic code expansion

2018 ◽  
Author(s):  
Toru Suzuki ◽  
Maki Asami ◽  
Sanjay G. Patel ◽  
Louis Y. P. Luk ◽  
Yu-Hsuan Tsai ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Genetic Code ◽  
Genome Editing ◽  
Active Form ◽  
Mammalian Genome ◽  
Gene Drive ◽  
Genetic Code Expansion ◽  
Or Gene ◽  
Gene Drives

AbstractMultiple applications of genome editing by CRISPR-Cas9 necessitate stringent regulation and Cas9 variants have accordingly been generated whose activity responds to small ligands, temperature or light. However, these approaches are often impracticable, for example in clinical therapeutic genome editing in situ or gene drives in which environmentally-compatible control is paramount. With this in mind, we have developed heritable Cas9-mediated mammalian genome editing that is acutely controlled by the cheap lysine derivative, Lys(Boc) (BOC). Genetic code expansion permitted non-physiological BOC incorporation such that Cas9 (Cas9BOC) was expressed in a full-length, active form in cultured somatic cells only after BOC exposure. Stringently BOC-dependent, heritable editing of transgenic and native genomic loci occurred when Cas9BOC was expressed at the onset of mouse embryonic development from cRNA or Cas9BOC transgenic females. The tightly controlled Cas9 editing system reported here promises to have broad applications and is a first step towards purposed, spatiotemporal gene drive regulation over large geographical ranges.

scholarly journals Switchable genome editing via genetic code expansion

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Toru Suzuki ◽  
Maki Asami ◽  
Sanjay G. Patel ◽  
Louis Y. P. Luk ◽  
Yu-Hsuan Tsai ◽  
...  
Keyword(s):  
Genetic Code ◽  
Genome Editing ◽  
Genetic Code Expansion

scholarly journals Light-guided intrabodies for on-demand in situ target recognition in human cells

2021 ◽  
Author(s):  
Eike F. Joest ◽  
Christian Winter ◽  
Joshua S. Wesalo ◽  
Alexander Deiters ◽  
Robert Tampé
Keyword(s):  
Genetic Code ◽  
Target Recognition ◽  
Living Cells ◽  
Human Cells ◽  
On Demand ◽  
Genetic Code Expansion

Nanobodies are ideal to visualize and modulate targets in living cells. We designed a versatile platform for generating photo-conditional intrabodies by genetic code expansion. After illumination, the intrabodies show fast and stable binding.

Structural Basis for Genetic-Code Expansion with Various Bulky Lysine Derivatives by an Engineered Pyrrolysyl-tRNA Synthetase

2018 ◽  
Author(s):  
Tatsuo Yanagisawa ◽  
Mitsuo Kuratani ◽  
Eiko Seki ◽  
Nobumasa Hino ◽  
Kensaku Sakamoto ◽  
...  
Keyword(s):  
Genetic Code ◽  
Trna Synthetase ◽  
Structural Basis ◽  
Genetic Code Expansion

scholarly journals DnaA, the Initiator of Escherichia coliChromosomal Replication, Is Located at the Cell Membrane

2000 ◽  
Vol 182 (9) ◽  
pp. 2604-2610 ◽  
Author(s):  
Gillian Newman ◽  
Elliott Crooke
Keyword(s):  
Cell Membrane ◽  
Spatial Organization ◽  
Active Form ◽  
Chromosomal Replication ◽  
E Coli ◽  
Dnaa Protein ◽  
Section Electron ◽  
Acidic Phospholipids

ABSTRACT Given the lack of a nucleus in prokaryotic cells, the significance of spatial organization in bacterial chromosome replication is only beginning to be fully appreciated. DnaA protein, the initiator of chromosomal replication in Escherichia coli, is purified as a soluble protein, and in vitro it efficiently initiates replication of minichromosomes in membrane-free DNA synthesis reactions. However, its conversion from a replicatively inactive to an active form in vitro occurs through its association with acidic phospholipids in a lipid bilayer. To determine whether the in situ residence of DnaA protein is cytoplasmic, membrane associated, or both, we examined the cellular location of DnaA using immunogold cryothin-section electron microscopy and immunofluorescence. Both of these methods revealed that DnaA is localized at the cell membrane, further suggesting that initiation of chromosomal replication in E. coli is a membrane-affiliated event.

scholarly journals Transferability of N-terminal mutations of pyrrolysyl-tRNA synthetase in one species to that in another species on unnatural amino acid incorporation efficiency

Amino Acids ◽  
2020 ◽  
Author(s):  
Thomas L. Williams ◽  
Debra J. Iskandar ◽  
Alexander R. Nödling ◽  
Yurong Tan ◽  
Louis Y. P. Luk ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Genetic Code ◽  
Unnatural Amino Acids ◽  
Trna Synthetase ◽  
Unnatural Amino Acid ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Genetic Code Expansion ◽  
Incorporation Efficiency

AbstractGenetic code expansion is a powerful technique for site-specific incorporation of an unnatural amino acid into a protein of interest. This technique relies on an orthogonal aminoacyl-tRNA synthetase/tRNA pair and has enabled incorporation of over 100 different unnatural amino acids into ribosomally synthesized proteins in cells. Pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNA from Methanosarcina species are arguably the most widely used orthogonal pair. Here, we investigated whether beneficial effect in unnatural amino acid incorporation caused by N-terminal mutations in PylRS of one species is transferable to PylRS of another species. It was shown that conserved mutations on the N-terminal domain of MmPylRS improved the unnatural amino acid incorporation efficiency up to five folds. As MbPylRS shares high sequence identity to MmPylRS, and the two homologs are often used interchangeably, we examined incorporation of five unnatural amino acids by four MbPylRS variants at two temperatures. Our results indicate that the beneficial N-terminal mutations in MmPylRS did not improve unnatural amino acid incorporation efficiency by MbPylRS. Knowledge from this work contributes to our understanding of PylRS homologs which are needed to improve the technique of genetic code expansion in the future.

scholarly journals Novel combination of CRISPR-based gene drives eliminates resistance and localises spread

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicky R. Faber ◽  
Gus R. McFarlane ◽  
R. Chris Gaynor ◽  
Ivan Pocrnic ◽  
C. Bruce A. Whitelaw ◽  
...  
Keyword(s):  
Driving Forces ◽  
Spatial Models ◽  
Cost Effective ◽  
Biodiversity Loss ◽  
Invasive Pest ◽  
Economic Losses ◽  
Sciurus Carolinensis ◽  
Gene Drive ◽  
Grey Squirrel ◽  
Gene Drives

AbstractInvasive species are among the major driving forces behind biodiversity loss. Gene drive technology may offer a humane, efficient and cost-effective method of control. For safe and effective deployment it is vital that a gene drive is both self-limiting and can overcome evolutionary resistance. We present HD-ClvR in this modelling study, a novel combination of CRISPR-based gene drives that eliminates resistance and localises spread. As a case study, we model HD-ClvR in the grey squirrel (Sciurus carolinensis), which is an invasive pest in the UK and responsible for both biodiversity and economic losses. HD-ClvR combats resistance allele formation by combining a homing gene drive with a cleave-and-rescue gene drive. The inclusion of a self-limiting daisyfield gene drive allows for controllable localisation based on animal supplementation. We use both randomly mating and spatial models to simulate this strategy. Our findings show that HD-ClvR could effectively control a targeted grey squirrel population, with little risk to other populations. HD-ClvR offers an efficient, self-limiting and controllable gene drive for managing invasive pests.

scholarly journals ASIC Activation Mechanisms Delineated through Genetic Code Expansion

2021 ◽  
Vol 120 (3) ◽  
pp. 338a
Author(s):  
Matthew L. Rook ◽  
Tyler A. Couch ◽  
Jackson Hernandez ◽  
Alison J. Frontier ◽  
David M. MacLean
Keyword(s):  
Genetic Code ◽  
Activation Mechanisms ◽  
Genetic Code Expansion

Context effects of genetic code expansion by stop codon suppression

2018 ◽  
Vol 46 ◽  
pp. 146-155 ◽  
Author(s):  
Yonatan Chemla ◽  
Eden Ozer ◽  
Itay Algov ◽  
Lital Alfonta
Keyword(s):  
Genetic Code ◽  
Context Effects ◽  
Stop Codon ◽  
Genetic Code Expansion
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