Combined fluorescent seed selection and multiplex CRISPR/Cas9 assembly for fast generation of multiple Arabidopsis mutants

Multiplex CRISPR-Cas9-based genome editing is an efficient method for targeted disruption of gene function in plants. Use of CRISPR-Cas9 has increased rapidly in recent years and is becoming a routine method for generating single and higher order Arabidopsis mutants. To facilitate rapid and efficient use of CRISPR/Cas9 for Arabidopsis research, we developed a CRISPR/Cas9-based toolbox for generating large deletions at multiple genomic loci, using two-color fluorescent seed selection. In our system, up-to eight gRNAs can be routinely introduced into a binary vector carrying either FastRed, FastGreen or FastCyan fluorescent seed selection cassette. Both, FastRed and FastGreen binary vectors, can be co-transformed as a cocktail via floral dip to introduce sixteen gRNAs at the same time. The seeds can be screened either for red or green fluorescence, or for the presence of both colors at the same time. Our approach provides fast and flexible cloning, avoids very big constructs and enables screening different order mutants in the same generation. Importantly, in the second generation after transformation, Cas9 free plants are identified simply by screening the dark, non-fluorescent seeds. Our collection of binary vectors allows to choose between two widely-used promoters to drive Cas enzymes, either the egg cell-specific (pEC1.2) or ubiquitous promoter (PcUBi4-2). Available enzymes are classical Cas9, a recently reported, intron-optimized version or Cpf1 (Cas12a). Finally, we have taken care to introduce convenient restriction sites flanking promoter, Cas9 and fluorescent selection cassette in the final T-DNA vectors, thus allowing straightforward swapping of all three elements for further adaptation and improvement of the system.

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Combined fluorescent seed selection and multiplex CRISPR/Cas9 assembly for fast generation of multiple Arabidopsis mutants

Plant Methods ◽

10.1186/s13007-021-00811-9 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Robertas Ursache ◽

Satoshi Fujita ◽

Valérie Dénervaud Tendon ◽

Niko Geldner

Keyword(s):

Gene Function ◽

De Novo ◽

Gene Families ◽

Higher Order ◽

Egg Cell ◽

Petroselinum Crispum ◽

Seed Selection ◽

Genetic Redundancy ◽

Binary Vectors ◽

Selection Cassette

Abstract Background Multiplex CRISPR-Cas9-based genome editing is an efficient method for targeted disruption of gene function in plants. Use of CRISPR-Cas9 has increased rapidly in recent years and is becoming a routine method for generating single and higher order Arabidopsis thaliana mutants. Low entry, reliable assembly of CRISPR/Cas9 vectors and efficient mutagenesis is necessary to enable a maximum of researchers to break through the genetic redundancy within plant multi-gene families and allow for a plethora of gene function studies that have been previously unachievable. It will also allow routine de novo generation of mutations in ever more complex genetic backgrounds that make introgression of pre-existing alleles highly cumbersome. Results To facilitate rapid and efficient use of CRISPR/Cas9 for Arabidopsis research, we developed a CRISPR/Cas9-based toolbox for generating mutations at multiple genomic loci, using two-color fluorescent seed selection. In our system, up-to eight gRNAs can be routinely introduced into a binary vector carrying either a FastRed, FastGreen or FastCyan fluorescent seed selection cassette. FastRed and FastGreen binary vectors can be co-transformed as a cocktail via floral dip to introduce sixteen gRNAs at the same time. The seeds can be screened either for red or green fluorescence, or for the presence of both colors. Importantly, in the second generation after transformation, Cas9 free plants are identified simply by screening the non-fluorescent seeds. Our collection of binary vectors allows to choose between two widely-used promoters to drive Cas enzymes, either the egg cell-specific (pEC1.2) from A. thaliana or the constitutive promoter from Petroselinum crispum (PcUBi4-2). Available enzymes are “classical” Cas9 codon-optimized for A. thaliana and a recently reported, intron-containing version of Cas9 codon-optimized for Zea mays, zCas9i. We observed the highest efficiency in producing knockout phenotypes by using intron-containing zCas9i driven under egg-cell specific pEC1.2 promoter. Finally, we introduced convenient restriction sites flanking promoter, Cas9 and fluorescent selection cassette in some of the T-DNA vectors, thus allowing straightforward swapping of all three elements for further adaptation and improvement of the system. Conclusion A rapid, simple and flexible CISPR/Cas9 cloning system was established that allows assembly of multi-guide RNA constructs in a robust and reproducible fashion, by avoiding generation of very big constructs. The system enables a flexible, fast and efficient screening of single or higher order A. thaliana mutants.

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Generation of selectable marker-free transgenic rice using double right-border (DRB) binary vectors

Functional Plant Biology ◽

10.1071/pp00129 ◽

2001 ◽

Vol 28 (3) ◽

pp. 241 ◽

Cited By ~ 8

Author(s):

Hui-Juan Lu ◽

Xue-Rong Zhou ◽

Zhu-Xun Gong ◽

Narayana M. Upadhyaya

Keyword(s):

Selectable Marker ◽

Binary Vector ◽

Marker Gene ◽

Marker Genes ◽

Binary Vectors ◽

Selectable Marker Genes ◽

Right Border ◽

Marker Free ◽

Dna Vectors ◽

Transgenic Progeny

Currently employed transformation systems require selectable marker genes encoding antibiotic or herbicide resistance, along with the gene of interest (GOI), to select transformed cells from among a large population of untransformed cells. The continued presence of these selectable markers, especially in food crops such as rice (Oryza sativa L.), is of increasing public concern. Techniques based on DNA recombination and Agrobacterium-mediated co-transformation with two binary vectors in a single or two different Agrobacterium strains, or with super-binary vectors carrying two sets of T-DNA border sequences (twin T-DNA vectors), have been employed by researchers to produce selectable marker-free (SMF) transgenic progeny. We have developed a double right-border (DRB) binary vector carrying two copies of T-DNA right-border (RB) sequences flanking a selectable marker gene, followed by a GOI and one copy of the left border sequence. Two types of T-DNA inserts, one initiated from the first RB containing both the selectable gene and the GOI, and the other from the second RB containing only the GOI, were expected to be produced and integrated into the genome. In the subsequent generation, these inserts could segregate away from each other, allowing the selection of the progeny with only the GOI. We tested this vector using two selectable marker genes and successfully obtained progeny plants in which the second selectable marker gene segregated away from the first. Using the DRB binary vector system, we recovered SMF transgenic lines containing a rice ragged stunt virus (RRSV)-derived synthetic resistance gene in the rice cultivars Jarrah and Xiu Shui. Approximately 36–64% of the primary transformants of these cultivars yielded SMF progeny. Among SMF Jarrah transgenic progeny <50% of plants contained the RRSV transgene. Thus, we have developed an efficient vector for producing SMF plants that allows straightforward cloning of any GOIs in comparison with the published ‘twin T-DNA’ vectors.

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Immunogold and immunoblot studies on a cell surface protein found in primary mesenchyme cells and in the cortical secretory vesicles of the sea urchin egg

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128444 ◽

1987 ◽

Vol 45 ◽

pp. 832-833

Author(s):

G.L. Decker ◽

M.C. Valdizan

Keyword(s):

Cell Surface ◽

Sea Urchin ◽

Surface Protein ◽

Egg Cell ◽

Secretory Vesicles ◽

Cell Surface Protein ◽

Surface Complexes ◽

Mesenchyme Cells ◽

Lowicryl K4m ◽

Primary Mesenchyme Cells

A monoclonal antibody designated MAb 1223 has been used to show that primary mesenchyme cells of the sea urchin embryo express a 130-kDa cell surface protein that may be directly involved in Ca2+ uptake required for growth of skeletal spicules. Other studies from this laboratory have shown that the 1223 antigen, although in relatively low abundance, is also expressed on the cell surfaces of unfertilized eggs and on the majority of blastomeres formed prior to differentiation of the primary mesenchyme cells.We have studied the distribution of 1223 antigen in S. purpuratus eggs and embryos and in isolated egg cell surface complexes that contain the cortical secretory vesicles. Specimens were fixed in 1.0% paraformaldehyde and 1.0% glutaraldehyde and embedded in Lowicryl K4M as previously reported. Colloidal gold (8nm diameter) was prepared by the method of Mulpfordt.

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Information-Seeking on the Internet

Crisis ◽

10.1027/0227-5910/a000307 ◽

2015 ◽

Vol 36 (3) ◽

pp. 211-219 ◽

Cited By ~ 11

Author(s):

Vinod Singaravelu ◽

Anne Stewart ◽

Joanna Adams ◽

Sue Simkin ◽

Keith Hawton

Keyword(s):

At Risk ◽

Young People ◽

Information Seeking ◽

Significant Proportion ◽

The Internet ◽

Search Terms ◽

Specific Advice ◽

Restriction Sites ◽

Self Harm ◽

Negative Tone

Abstract. Background: The Internet is used by young people at risk of self-harm to communicate, find information, and obtain support. Aims: We aimed to identify and analyze websites potentially accessed by these young people. Method: Six search terms, relating to self-harm/suicide and depression, were input into four search engines. Websites were analyzed for access, content/purpose, and tone. Results: In all, 314 websites were included in the analysis. Most could be accessed without restriction. Sites accessed by self-harm/suicide search terms were mostly positive or preventive in tone, whereas sites accessed by the term ways to kill yourself tended to have a negative tone. Information about self-harm methods was common with specific advice on how to self-harm in 15.8% of sites, encouragement of self-harm in 7.0%, and evocative images of self-harm/suicide in 20.7%. Advice on how to get help was given in 56.1% of sites. Conclusion: Websites relating to suicide or self-harm are easily accessed. Many sites are potentially helpful. However, a significant proportion of sites are potentially harmful through normalizing or encouraging self-harm. Enquiry regarding Internet use should be routinely included while assessing young people at risk.

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Scaling properties of coexistence curves for polymer solutions in terms of different order parameters

Journal de Physique ◽

10.1051/jphys:0198900500120157300 ◽

1989 ◽

Vol 50 (12) ◽

pp. 1573-1579 ◽

Cited By ~ 5

Author(s):

Yu. B. Mel'nichenko ◽

V.V. Klepko

Keyword(s):

Polymer Solutions ◽

Order Parameters ◽

Scaling Properties ◽

Different Order

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Characterization of Partial Gene Deletions in Type III von Willebrand Disease with Alloantibody Inhibitors

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648835 ◽

1994 ◽

Vol 72 (02) ◽

pp. 180-185 ◽

Cited By ~ 22

Author(s):

David J Mancuso ◽

Elodee A Tuley ◽

Ricardo Castillo ◽

Norma de Bosch ◽

Pler M Mannucci ◽

...

Keyword(s):

Von Willebrand Factor ◽

Von Willebrand Disease ◽

Pcr Analysis ◽

Gene Deletions ◽

Factor Gene ◽

Type Iii ◽

Large Deletions ◽

Von Willebrand ◽

Willebrand Factor

Summaryvon Willebrand factor gene deletions were characterized in four patients with severe type III von Willebrand disease and alloantibodies to von Willebrand factor. A PCR-based strategy was used to characterize the boundaries of the deletions. Identical 30 kb von Willebrand factor gene deletions which include exons 33 through 38 were identified in two siblings of one family by this method. A small 5 base pair insertion (CCTGG) was sequenced at the deletion breakpoint. PCR analysis was used to detect the deletion in three generations of the family, including two family members who are heterozygous for the deletion. In a second family, two type III vWD patients, who are distant cousins, share an -56 kb deletion of exons 22 through 43. The identification and characterization of large vWF gene deletions in these type III vWD patients provides further support for the association between large deletions in both von Willebrand factor alleles and the development of inhibitory alloantibodies.

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