We thank Chunxin Wang for constructing pTSO2::GUS and for photos in Figure 1, Detlef Weigel for sharing the GUS-foolproof protocol, Paja Sijacic, and Courtney Hollender for helpful comments. Research in Z. L s laboratory is supported by the US National Science Foundation (IOB0616096 and MCB0744752). Z.L. is partially supported by the University of Maryland Agricultural Experiment Station.

I. Floral-dip transformation of Arabidopsis thaliana
<ol>
	<li>Approximately 1 month prior to transformation, sow Arabidopsis seeds onto 4 to 8 pots (5 inch square pots) with approximately 10-15 plants per pot. For plants with normal fertility, 4 pots of plants per plasmid construct will be sufficient. If one has to transform mutant Arabidopsis with reduced fertility, increase the number of pots accordingly.</li>
	<li>The plants are grown under standard conditions (16 hr light and 8 hr dark at 22&#176;C). If plants are grown under shorter day or lower temperature, they will take longer to flower and longer to be ready for transformation. Good plant care will ensure healthy plants, which are essential for successful transformation.</li>
	<li>When the plants have just bolted and begun to flower. They are now ready for transformation. To increase transformation efficiency, 3-4 days before the transformation, trim off the main inflorescence shoots as soon as they have bolted to encourage more secondary shoot formation. Water the plants the day before transformation. This ensures that the soil will not soak up too much infiltration media during floral-dipping.</li>
	<li>Two days prior to transformation, inoculate 40ml LB containing appropriate antibiotics (in the case of pTSO2::GUS, 50 &#956;g/ml Kanamycin) with Agrobacterium tumefaciens strain GV3101 carrying the pTSO2::GUS construct. The pTSO2::GUS is cloned in the pBIN20 vector that possesses NPTII gene that confers resistance to Kanamycin3. Grow overnight in a shaking incubator at 28-30&#176;C.</li>
	<li>The following day, transfer 8ml of the overnight culture into 400ml of LB containing 50 &#956;g/ml Kanamycin. Grow overnight in a shaking incubator at 28-30&#176;C.</li>
	<li>On the day of transformation, when the OD600 of the Agrobacterium culture reaches approximately 0.8 (OD600 between 0.5 to1 are acceptable), spin down the Agrobacterium overnight culture at for 8 minutes at 5000rpm.</li>
	<li>Resuspend the Agrobacterium pellet in 1 L (liter) of infiltration media (10mM MgCl2, 5% sucrose, 0.44mM 6-benzyladenine (BA), 0.3% silwet L-77, 1x Gamborg s vitamin solution and autoclaved water). The medium does not need to be autoclaved but needs to be made fresh. Pour the 1 L Agrobacterium-containing infiltration medium into a dish (such as 8&#34;x15&#34;x2&#34; Pyrex glass dish).</li>
	<li>Invert the pot (plants won&#39;t fall off) and dip all aerial parts of the plants into the infiltration solution, hold for 5 minutes one pot at a time. While all aerial parts of the plant are immersed in the infiltration medium, avoid letting soil soak up any of the infiltration media to reduce chances of fungal growth on the soil.</li>
	<li>After dipping, place all dipped pots on their side on several layers of paper towel in a tray. The paper towels soak up access amount of infiltration media. Cover the tray with plastic wrap to ensure high humidity. Place the tray into plant growth chamber.</li>
	<li>On the following day, remove the plastic wrap and paper towels, and place pots upright. Do not water these plants for four to five more days. Afterwards, maintain the plants normally until they set seeds and collect seeds in bulk.</li>
	<li>Pour plates (150x15mm petri dish) with MS medium containing 50 &#956;g/ml Kanamycin (weight 2.2g Murashige and Skoog basal salt without vitamin, dissolve in 500 ml water, pH to 5.8 with 1M NaOH, add 4 gram agar, autoclave, cool and add Kanamycin to 50 &#956;g/ml final concentration). Plates are kept in 4&#176;C until needed.</li>
	<li>To select for antibiotic-resistant transgenic plants, one needs to screen 20,000 seeds at minimum. 0.1 gram is about 5000 seeds. Weight and estimate the amount of seeds.</li>
	<li>Sterilize seeds by wash them in 15 ml Falcon tube with 70% ethanol for 30 seconds. Wash seeds with sterile water once. Soak the seeds for 30 seconds in a solution containing 1:10 dilution of store-bought 5% bleach (Clorox). Rinse seeds with sterile water three to six times. In sterile hood, pipette about 5000 seeds onto each MS (Kanamycin) plate, spread the seeds evenly on the plate, seal the plates with Micropore 3M tape to avoid contamination.</li>
	<li>Incubate the plates at 4&#176;C in the dark for 3-4 days, then transfer the plates to a chamber (could be the same plant growth chamber). After about 14 days, transgenic seedlings stay green but the non-transgenic ones are turning pale and dying. Transfer the transgenic seedlings to soil by slowing pulling the roots out from the medium and placed them in soil.</li>
</ol>
II. Examining pTSO2::GUS expression patterns
<ol>
	<li>Harvest pTSO2::GUS transgenic seedlings and place them in cold 90% acetone in a glass scintillation vial or microfuge tubes that are kept on ice. Polystyrene microtiter plates (not polypropylene) can also be used if one analyzes a large numbers of samples.</li>
	<li>After all samples are harvested, place the vials at room temperature for 20 minutes. During this time make up fresh staining buffer without x-Gluc (0.2% Triton x-100, 50mM NaHPO4 Buffer pH7.2, 2mM Potassium Ferrocyanide, 2mM Potassium Ferricyanide) and place on ice.</li>
	<li>Remove acetone from the samples and add the staining buffer.</li>
	<li>Make up x- Gluc staining solution (0.2% Triton x-100, 50mM NaHPO4 Buffer pH7.2, 2mM Potassium Ferrocyanide, 2mM Potassium Ferricyanide, 2mM x-gluc). Remove the staining buffer from samples and add the staining buffer containing x-Gluc to the samples.</li>
	<li>Infiltrate the samples under a vacuum for 15 to 20 minutes. Release the vacuum slowly and verify that all the samples sink beneath the surface of the staining solution. If necessary, repeat infiltration until all samples sink after the vacuum is released.</li>
	<li>Incubate samples at 37&#176;C overnight in the staining buffer with x-Gluc.</li>
	<li>Remove samples from incubator and remove staining buffer. Wash the samples in successive ethanol series (20%, 35% and 50% ethanol) at room temperature for 30 minutes each change.</li>
	<li>Fix the tissues in FAA fixative (50% Ethanol, 5% Formaldehyde, 10% Acetic acid, rest water) for 30 minutes at room temperature. Remove FAA and add 70% ethanol. At this point the tissues can be visualized and photographed under a dissecting microscope equipped with a digital camera. A dark blue color indicates where TSO2 is expressed (Figure 1). Alternatively, the tissues can be stored at 4&#176;C for later viewing. 
	 
	<img alt="Figure 1" src="/files/ftp_upload/1952/1952fig1.jpg" /> 
	Figure 1. pTSO2::GUS expression in transgenic seedlings (A), lateral roots (B), and root tip (C). Note that TSO2 promoter is highly active in young and dividing tissues. The sporadic expression pattern shown in (C) is typical of genes expressed in specific cell cycle phases.</li>
</ol>
Representative Results
When done correctly, transformation efficiency should be approximately 0.1-0.2%. In another word, one should get 5-10 transgenic seedlings by screening every 5000 seeds. On average, about 100 transgenic lines can be obtained by transforming 4 pots of wild-type plants.
For transgenic seedlings containing the pTSO2::GUS construct3, dark blue color reflecting GUS activity is found in actively dividing cells including young leaves, shoot apex, root tip, and lateral root primordia (Figure 1). The non-uniform sporadic pattern is characteristic of cell cycle phase-specific expression.

<ol>
	<li>Clough, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Floral+dip:+agrobacterium-mediated+germ+line+transformation.">Floral dip: agrobacterium-mediated germ line transformation.</a> Methods Mol Biol. 286, 91-91 (2005).</li><li>Clough, S. J., Bent, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Floral+dip:+a+simplified+method+for+Agrobacterium-mediated+transformation+of+Arabidopsis+thaliana.">Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana.</a> Plant J. 16 (6), 735-735 (1998).</li><li>Wang, C., Liu, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arabidopsis+ribonucleotide+reductases+are+critical+for+cell+cycle+progression,+DNA+damage+repair,+and+plant+development.">Arabidopsis ribonucleotide reductases are critical for cell cycle progression, DNA damage repair, and plant development.</a> Plant Cell. 18 (2), 350-350 (2006).</li></ol>

No conflicts of interest declared.

The efficiency of transformation is determined by many different factors, which are discussed below:
<ol>
<li> The health of the plants and their age are of primary importance. Approximately one month old plants producing numerous immature floral buds are ideal. Trimming off primary shoots to encourage secondary shoot formation 3-4 days before transformation will increase transformation efficiency. Older plants will give rise to transformants but at a lower rate.</li>
<li> Fertility of the plants is important. If one...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>6-benzyladenine</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>852430</td>
<td>&nbsp;</td>
<tr>
<td>Silwet-77</td>
<td>&nbsp;</td>
<td>Crompton Corp.</td>
<td>&nbsp;</td>
<td>Toxic, wear gloves</td>
</tr>
<tr>
<td>Murashige and Skoog Basal medium (MS)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M5519</td>
<td>&nbsp;</td>
<tr>
<td>Gamborg's vitamin solution 1000X</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>G1019</td>
<td>&nbsp;</td>
<tr>
<td>X-Gluc (5-bromo-4-chloro-3-indolyl &beta;-D-glucuronide cyclohexamine salt</td>
<td>&nbsp;</td>
<td>Biosynth</td>
<td>B-7300</td>
<td>Toxic, light sensitive keep in the dark</td>
</tr>
<tr>
<td>Micropore 3M Tape</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>19027761</td>
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floral-dip transformation of arabidopsis thaliana to examine ptso2::&beta;-glucuronidase reporter gene expression

The ability to introduce foreign genes into an organism is the foundation for modern biology and biotechnology. In the model flowering plant Arabidopsis thaliana, the floral-dip transformation method1-2 has replaced all previous methods because of its simplicity, efficiency, and low cost. Specifically, shoots of young flowering Arabidopsis plants are dipped in a solution of Agrobacterium tumefaciens carrying specific plasmid constructs. After dipping, the plants are returned to normal growth and yield seeds, a small percentage of which are transformed with the foreign gene and can be selected for on medium containing antibiotics. This floral-dip method significantly facilitated Arabidopsis research and contributed greatly to our understanding of plant gene function. In this study, we use the floral-dip method to transform a reporter gene, &beta;-glucuronidase (GUS), under the control of TSO2 promoter. TSO2, coding for the Ribonucleotide Reductase (RNR) small subunit3, is a cell cycle regulated gene essential for dNDP biosynthesis in the S-phase of the cell cycle. Examination of GUS expression in transgenic Arabidopsis seedlings shows that TSO2 is expressed in actively dividing tissues. The reported experimental method and materials can be easily adapted not only for research but also for education at high school and college levels.

Watch this Scientific Journal Video about Floral-dip Transformation of Arabidopsis thaliana to Examine pTSO2::Î²-glucuronidase Reporter Gene Expression at JoVE.com

Floral-dip Transformation of Arabidopsis thaliana to Examine pTSO2::&amp;#946;-glucuronidase Reporter Gene Expression

This article illustrates the floral-dip method of Agrobacterium tumefaciens -mediated transformation of Arabidopsis thaliana. By introducing a cell-cycle regulated promoter-reporter, pTSO2::&beta;-glucuronidase (GUS), into Arabidopsis, we illustrates how one detects GUS reporter expression in transgenic seedlings.

Floral-dip Transformation of Arabidopsis thaliana to Examine pTSO2::&beta;-glucuronidase Reporter Gene Expression

The ability to introduce foreign genes into an organism is the foundation for modern biology and biotechnology. In the model flowering plant Arabidopsis ...

floral-dip-transformation-arabidopsis-thaliana-to-examine-ptso2

Research

JoVE Journal

Biology

36.0K vues.  University of Maryland College Park. Cet article illustre l'floral dip méthode de Agrobacterium tumefaciens Transformation médiée par des Arabidopsis thaliana. En introduisant un cycle cellulaire régulé promoteur-rapporteur, PTSO2:: β-glucuronidase (GUS), Dans Arabidopsis, Nous montre comment on détecte l'expression rapporteur GUS dans des plants transgéniques.

Vidéo: Floral-dip Transformation of Arabidopsis thaliana to Examine pTSO2::&#946;-glucuronidase Reporter Gene Expression

The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell  electroporation system and Gene Pulser  electroporation buffer were specifically developed to transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells.This video demonstrates how to establish primary hematopoietic cell cultures from murine bone marrow, and then prepare them for electroporation in the MXcell system. We begin by isolating femur and tibia. Bone marrow from both femur and tibia are then harvested and cultures are established. Cultured bone marrow cells are then transfected and analyzed.

This procedure describes how to establish primary hematopoietic cell cultures from murine bone marrow and is followed by transfection using the Gene Pulser MXCell electroporation system.

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

Using the Gene Pulser MXcell Electroporation System to Transfect Primary Cells with High Efficiency

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

This procedure shows how to use the Gene Pulser MXcell electroporation system to rapidly and easily identify the best electroporation conditions for mouse embryonic fibroblasts (MEFs) or other primary cells. Considerations for troubleshooting are also discussed in the associated video.

Using an Automated Cell Counter to Simplify Gene Expression Studies: siRNA Knockdown of IL-4 Dependent Gene Expression in Namalwa Cells

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only to study the effects of downregulating single genes, but also to interrogate signaling pathways and other complex interaction networks.  These pathway analyses require both the use of relevant cellular models and methods that cause less perturbation to the cellular physiology.  Electroporation is increasingly being used as an effective way to introduce siRNA and other nucleic acids into difficult to transfect cell lines and primary cells without altering the signaling pathway under investigation. There are multiple critical steps to a successful siRNA experiment, and there are ways to simplify the work while improving the data quality at several experimental stages.  To help you get started with your siRNA mediated gene knockdown project, we will demonstrate how to perform a pathway study complete from collecting and counting the cells prior to electroporation through post transfection real-time PCR gene expression analysis.  The following study investigates the role of the transcriptional activator STAT6 in IL-4 dependent gene expression of CCL17 in a Burkitt lymphoma cell line (Namalwa).  The techniques demonstrated are useful for a wide range of siRNA-based experiments on both adherent and suspension cells.  We will also show how to streamline cell counting with the TC10 automated cell counter, how to electroporate multiple samples simultaneously using the MXcell electroporation system, and how to simultaneously assess RNA quality and quantity with the Experion automated electrophoresis system.

This procedure describes a quick and easy workflow to introduce siRNA into difficult to transfect cell lines and follow gene expression by real-time PCR. Use of an automated cell counter, multi-well electroporation plate, and automated electrophoresis station provide quick and reliable results without the need for expensive robotic handling.

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only ...

Investigating Tissue- and Organ-specific Phytochrome Responses using FACS-assisted Cell-type Specific Expression Profiling in Arabidopsis thaliana

Light mediates an array of developmental and adaptive processes throughout the life cycle of a plant. Plants utilize light-absorbing molecules called photoreceptors to sense and adapt to light. The red/far-red light-absorbing phytochrome photoreceptors have been studied extensively. Phytochromes exist as a family of proteins with distinct and overlapping functions in all higher plant systems in which they have been studied1. Phytochrome-mediated light responses, which range from seed germination through flowering and senescence, are often localized to specific plant tissues or organs2. Despite the discovery and elucidation of individual and redundant phytochrome functions through mutational analyses, conclusive reports on distinct sites of photoperception and the molecular mechanisms of localized pools of phytochromes that mediate spatial-specific phytochrome responses are limited. We designed experiments based on the hypotheses that specific sites of phytochrome photoperception regulate tissue- and organ-specific aspects of photomorphogenesis, and that localized phytochrome pools engage distinct subsets of downstream target genes in cell-to-cell signaling. We developed a biochemical approach to selectively reduce functional phytochromes in an organ- or tissue-specific manner within transgenic plants. Our studies are based on a bipartite enhancer-trap approach that results in transactivation of the expression of a gene under control of the Upstream Activation Sequence (UAS) element by the transcriptional activator GAL43. The biliverdin reductase (BVR) gene under the control of the UAS is silently maintained in the absence of GAL4 transactivation in the UAS-BVR parent4. Genetic crosses between a UAS-BVR transgenic line and a GAL4-GFP enhancer trap line result in specific expression of the BVR gene in cells marked by GFP expression4. BVR accumulation in Arabidopsis plants results in phytochrome chromophore deficiency in planta5-7. Thus, transgenic plants that we have produced exhibit GAL4-dependent activation of the BVR gene, resulting in the biochemical inactivation of phytochrome, as well as GAL4-dependent GFP expression. Photobiological and molecular genetic analyses of BVR transgenic lines are yielding insight into tissue- and organ-specific phytochrome-mediated responses that have been associated with corresponding sites of photoperception4, 7, 8. Fluorescence Activated Cell Sorting (FACS) of GFP-positive, enhancer-trap-induced BVR-expressing plant protoplasts coupled with cell-type-specific gene expression profiling through microarray analysis is being used to identify putative downstream target genes involved in mediating spatial-specific phytochrome responses. This research is expanding our understanding of sites of light perception, the mechanisms through which various tissues or organs cooperate in light-regulated plant growth and development, and advancing the molecular dissection of complex phytochrome-mediated cell-to-cell signaling cascades.

Investigating Tissue- and Organ-specific Phytochrome Responses using FACS-assisted Cell-type Specific Expression Profiling in Arabidopsis thaliana

The molecular basis of spatial-specific phytochrome responses is being investigated using transgenic plants that exhibit tissue- and organ-specific phytochrome deficiencies. The isolation of specific cells exhibiting induced phytochrome chromophore depletion by Fluorescence-Activated Cell Sorting followed by microarray analyses is being utilized to identify genes involved in spatial-specific phytochrome responses.

Light mediates an array of developmental and adaptive processes throughout the life cycle of a plant. Plants utilize light-absorbing molecules called ...

In vitro Reconstitution of the Active T. castaneum Telomerase

Efforts to isolate the catalytic subunit of telomerase, TERT, in sufficient quantities for structural studies, have been met with limited success for more than a decade. Here, we present methods for the isolation of the recombinant Tribolium castaneum TERT (TcTERT) and the reconstitution of the active T. castaneum telomerase ribonucleoprotein (RNP) complex in vitro.
Telomerase is a specialized reverse transcriptase1 that adds short DNA repeats, called telomeres, to the 3' end of linear chromosomes2 that serve to protect them from end-to-end fusion and degradation. Following DNA replication, a short segment is lost at the end of the chromosome3 and without telomerase, cells continue dividing until eventually reaching their Hayflick Limit4. Additionally, telomerase is dormant in most somatic cells5 in adults, but is active in cancer cells6 where it promotes cell immortality7.
The minimal telomerase enzyme consists of two core components: the protein subunit (TERT), which comprises the catalytic subunit of the enzyme and an integral RNA component (TER), which contains the template TERT uses to synthesize telomeres8,9. Prior to 2008, only structures for individual telomerase domains had been solved10,11. A major breakthrough in this field came from the determination of the crystal structure of the active12, catalytic subunit of T. castaneum telomerase, TcTERT1.
Here, we present methods for producing large quantities of the active, soluble TcTERT for structural and biochemical studies, and the reconstitution of the telomerase RNP complex in vitro for telomerase activity assays. An overview of the experimental methods used is shown in Figure 1.

In vitro Reconstitution of the Active T. castaneum Telomerase

Efforts to isolate the catalytic subunit of telomerase, TERT, in sufficient quantities for structural studies, have been met with limited success for more than a decade. Here, we present methods for the isolation of the recombinant Tribolium castaneum TERT (TcTERT) and the reconstitution of the active T. castaneum telomerase ribonucleoprotein (RNP) complex in vitro.

Efforts to isolate the catalytic subunit of telomerase, TERT, in sufficient quantities for structural studies, have been met with limited success for more ...

Histochemical Staining of Arabidopsis thaliana Secondary Cell Wall Elements

Arabidopsis thaliana is a model organism commonly used to understand and manipulate various cellular processes in plants, and it has been used extensively in the study of secondary cell wall formation. Secondary cell wall deposition occurs after the primary cell wall is laid down, a process carried out exclusively by specialized cells such as those forming vessel and fiber tissues. Most secondary cell walls are composed of cellulose (40&#8211;50%), hemicellulose (25&#8211;30%), and lignin (20&#8211;30%). Several mutations affecting secondary cell wall biosynthesis have been isolated, and the corresponding mutants may or may not exhibit obvious biochemical composition changes or visual phenotypes since these mutations could be masked by compensatory responses. Staining procedures have historically been used to show differences on a cellular basis. These methods are exclusively visual means of analysis; nevertheless their role in rapid and critical analysis is of great importance. Congo red and calcofluor white are stains used to detect polysaccharides, whereas M&#228;ule and phloroglucinol are commonly used to determine differences in lignin, and toluidine blue O is used to differentially stain polysaccharides and lignin. The seemingly simple techniques of sectioning, staining, and imaging can be a challenge for beginners. Starting with sample preparation using the A. thaliana model, this study details the protocols of a variety of staining methodologies that can be easily implemented for observation of cell and tissue organization in secondary cell walls of plants.

Histochemical Staining of Arabidopsis thaliana Secondary Cell Wall Elements

Plant cell wall composition varies between tissue types and can include lignin, cellulose, hemicelluloses, and pectin. Various staining techniques have been developed to visualize differences at the cell-type level. This paper is a compilation of commonly used cell wall staining techniques.

Arabidopsis thaliana is a model organism commonly used to understand and manipulate various cellular processes in plants, and it has been used extensively ...

Analysis of Global RNA Synthesis at the Single Cell Level following Hypoxia

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a particular transcriptional program in order to mount an appropriate and coordinated cellular response. The cell possesses several oxygen sensor enzymes that require molecular oxygen as cofactor for their activity. These range from prolyl-hydroxylases to histone demethylases. The majority of studies analyzing cellular responses to hypoxia are based on cellular populations and average studies, and as such single cell analysis of hypoxic cells are seldom performed. Here we describe a method of analysis of global RNA synthesis at the single cell level in hypoxia by using Click-iT RNA imaging kits in an oxygen controlled workstation, followed by microscopy analysis and quantification.&nbsp; Using cancer cells exposed to hypoxia for different lengths of time, RNA is labeled and measured in each cell. This analysis allows the visualization of temporal and cell-to-cell changes in global RNA synthesis following hypoxic stress.

We describe a technique for analysis of global RNA synthesis in hypoxia using imaging. Click-chemistry labeling of RNA has not previously been performed under hypoxia and allows visualization of global RNA changes at the single cell level. This approach complements the existing averaged RNA techniques, allowing direct visualization of cell-to-cell changes in global RNA synthesis.

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a ...

Floral-Dip Transformation of Flax (Linum usitatissimum) to Generate Transgenic Progenies with a High Transformation Rate

Agrobacterium-mediated plant transformation via floral-dip is a widely used technique in the field of plant transformation and has been reported to be successful for many plant species. However, flax (Linum usitatissimum) transformation by floral-dip has not been reported. The goal of this protocol is to establish that Agrobacterium and the floral-dip method can be used to generate transgenic flax. We show that this technique is simple, inexpensive, efficient, and more importantly, gives a higher transformation rate than the current available methods of flax transformation.
In summary, inflorescences of flax were dipped in a solution of Agrobacterium carrying a binary vector plasmid (T-DNA fragment plus the Linum Insertion Sequence, LIS-1) for 1 - 2 min. The plants were laid flat on their side for 24 hr. Then, plants were maintained under normal growth conditions until the next treatment. The process of dipping was repeated 2 - 3 times, with approximately 10 - 14 day intervals between dipping. The T1 seeds were collected and germinated on soil. After approximately two weeks, treated progenies were tested by direct PCR; 2 - 3 leaves were used per plant plus the appropriate T-DNA primers. Positive transformants were selected and grown to maturity. The transformation rate was unexpectedly high, with 50 - 60% of the seeds from treated plants being positive transformants. This is a higher transformation rate than those reported for Arabidopsis thaliana and other plant species, using floral-dip transformation. It is also the highest, which has been reported so far, for flax transformation using other methods for transformation.

Floral-Dip Transformation of Flax Linum usitatissimum to Generate Transgenic Progenies with a High Transformation Rate

Here, we present a protocol to transform flax using Agrobacterium-mediated plant transformation via floral-dip. This protocol is simple to perform and inexpensive, yet yields a higher transformation rate than the current available methods for flax transformation.

Agrobacterium-mediated plant transformation via floral-dip is a widely used technique in the field of plant transformation and has been reported to be ...

Visualizing Stromule Frequency with Fluorescence Microscopy

Stromules, or "stroma-filled tubules", are narrow, tubular extensions from the surface of the chloroplast that are universally observed in plant cells but whose functions remain mysterious. Alongside growing attention on the role of chloroplasts in coordinating plant responses to stress, interest in stromules and their relationship to chloroplast signaling dynamics has increased in recent years, aided by advances in fluorescence microscopy and protein fluorophores that allow for rapid, accurate visualization of stromule dynamics. Here, we provide detailed protocols to assay stromule frequency in the epidermal chloroplasts of Nicotiana benthamiana, an excellent model system for investigating chloroplast stromule biology. We also provide methods for visualizing chloroplast stromules in vitro by extracting chloroplasts from leaves. Finally, we outline sampling strategies and statistical approaches to analyze differences in stromule frequencies in response to stimuli, such as environmental stress, chemical treatments, or gene silencing. Researchers can use these protocols as a starting point to develop new methods for innovative experiments to explore how and why chloroplasts make stromules.

Protocols to investigate the dynamics of chloroplast stromules, the stroma-filled tubules that extend from the surface of chloroplasts, are described.

Stromules, or "stroma-filled tubules", are narrow, tubular extensions from the surface of the chloroplast that are universally observed in plant cells but ...

Spatiotemporal Investigation of ERL1 Dynamics via Confocal Imaging

Image-Based Methods to Study Membrane Trafficking Events in Stomatal Lineage Cells

In eukaryotic cells, membrane components, including proteins and lipids, are spatiotemporally transported to their destination within the endomembrane system. This includes the secretory transport of newly synthesized proteins to the cell surface or the outside of the cell, the endocytic transport of extracellular cargoes or plasma membrane components into the cell, and the recycling or shuttling transport of cargoes between the subcellular organelles, etc. Membrane trafficking events are crucial to the development, growth, and environmental adaptation of all eukaryotic cells and, thus, are under stringent regulation. Cell-surface receptor kinases, which perceive ligand signals from the extracellular space, undergo both secretory and endocytic transport. Commonly used approaches to study the membrane trafficking events using a plasma membrane-localized leucine-rich-repeat receptor kinase, ERL1, are described here. The approaches include plant material preparation, pharmacological treatment, and confocal imaging setup. To monitor the spatiotemporal regulation of ERL1, this study describes the co-localization analysis between ERL1 and a multi-vesicular body marker protein, RFP-Ara7, the time series analysis of these two proteins, and the z-stack analysis of ERL1-YFP treated with the membrane trafficking inhibitors brefeldin A and wortmannin.

Author Spotlight: Image-Based Methods to Study Membrane Trafficking Events in Stomatal Lineage Cells  

Several commonly used methods are introduced here to study the membrane trafficking events of a plasma membrane receptor kinase. This manuscript describes detailed protocols including the plant material preparation, pharmacological treatment, and confocal imaging setup.

In eukaryotic cells, membrane components, including proteins and lipids, are spatiotemporally transported to their destination within the endomembrane ...