Name: an array-based comparative genomic hybridization platform for efficient detection of copy number variations in fast neutron-induced medicago truncatula mutants
Uploaded: 2017-11-08T15:00:00
Description: Watch this Scientific Journal Video about An Array-based Comparative Genomic Hybridization Platform for Efficient Detection of Copy Number Variations in Fast Neutron-induced Medicago truncatula Mutant

Funding of this work is provided in part by a grant from NSF Plant Genome Research (IOS-1127155).

NOTE: Figure 1 shows the five steps for the array CGH protocol. They are: 1) Preparation of plant materials; 2) Isolation of high quality DNA samples; 3) Labeling and purification of DNA samples; 4) Hybridization, washing, and scanning of whole genome arrays; and 5) CGH data analysis. M. truncatula whole genome tiling arrays contain a total of 971,041 unique oligo probes targeting more than 50,000 genes or gene models in the genome (See Table of Materials). The uniq...

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We have developed an array-based CGH platform for the detection and characterization of fast neutron bombardment (FNB)-induced mutants in M. truncatula cv. Jemalong A17. To demonstrate the use of the array CGH method in detecting gene mutations, we performed aCGH analysis of the mutant FN6191, which exhibited a hyper-nodulation phenotype in contrast to wild type plants, when inoculated with S. meliloti Sm1021. For segmentation analysis, a segment was deemed significant if the log2 ratio mean ...

Legumes (Fabaceae) are the third largest family of flowering plants, with many economically important species such as soybean (Glycine max) and alfalfa (Medicago sativa). Legume plants can interact with nitrogen-fixing soil bacteria, generally called Rhizobia to develop root nodules in which the atmospheric dinitrogen is reduced to ammonia for use by the host plant. As such, cultivation of legume crops requires little input of nitrogen fertilizers and thus contributes to sustainable agriculture. Legume crops produce leaves and seeds with high protein content, serving as excellent forage and grain crops. However, cultivated legume species generally have complex genome structures, making functional studies of genes that play key roles in legume-specific processes cumbersome. Medicago truncatula has been widely adopted as a model species for legume studies primarily because (1) it has a diploid genome with a relatively small haploid genome size (~550 Mbp); (2) plants can be stably transformed for gene functional studies; and (3) it is closely related to alfalfa (M. sativa), the queen of forages, and many other economically important crops for translational studies. Recently, the genome sequence of M. truncatula cv Jemalong A17 has been released1,2. Annotation of the genome shows that there are more than 50,000 predicted genes or gene models in the genome. To determine the function of most of the genes in the M. truncatula genome is a challenging task. To facilitate functional studies of genes, a comprehensive collection of mutants in the range of over 150,000 M1 lines has been generated using fast neutron bombardment (FNB) mutagenesis in M. truncatula cv Jemalong A173,4. Fast neutron, a high energy ionization mutagen, has been used in generating mutants in many plant species including Arabidopsis5,6, rice (Oryza sativa)7, tomato (Solanum lycopersicum), soybean (Glycine soja; G. max)8,9, barley (Hordeum vulgare), and Lotus japonicus10. A large portion of mutations derived from FNB mutagenesis are due to DNA deletions that range in size from a few base pairs to mega base pairs9,11. Many phenotype-associated genes have been successfully identified and characterized4,12,13,14,15,16,17,18,19. Previously, molecular cloning of the underlying genes from FNB mutants relied on a map-based approach, which is time consuming and limits the number of mutants to be characterized at the molecular level. Recently, several complimentary approaches including transcript-based methods, genome tiling array-based comparative genomic hybridization (CGH) for DNA copy number variation detection, and whole genome sequencing, have been employed to facilitate the characterization of deletion mutants in diverse organisms including animals and plants20,21,22,23,24,25,26,27,28,29,30,31.
To facilitate the characterization of FNB mutants in M. truncatula, a whole-genome array-based comparative genomic hybridization (CGH) platform has been developed and validated. As reported in animal systems, the array-based CGH platform allows detection of copy number variations (CNVs) at the whole genome level in M. truncatula FNB mutants. Furthermore, lesions can be confirmed by PCR and deletion borders can be identified by sequencing. Overall, the array CGH platform is an efficient and effective tool in identifying lesions in M. truncatula FNB mutants. Here, the array CGH procedure and PCR characterization of deletion borders in an M. truncatula FNB mutant are illustrated.
The following protocol provides experimental steps and information about reagents, equipment and analysis tools for researchers who are interested in carrying out whole genome array-based comparative genomic hybridization (CGH) analysis of copy number variations in plants. As an example, Medicago truncatula FN6191 mutant was used to identify deletion regions and candidate genes associated with mutant phenotypes. M. truncatula FN6191 mutant, originally isolated from a fast neutron bombardment-induced deletion mutant collection32 (see Table of Materials), exhibited a hyper-nodulation phenotype after inoculation with the soil bacterium, Sihorhizobium meliloti Sm1021, in contrast to wild type plants.

<table>
	<tbody>
		<tr>
			<td>Medicago truncatula genome array, 1 x 1 M</td>
			<td>Agilent</td>
			<td>G4123A</td>
			<td></td>
		</tr>
		<tr>
			<td>Medicago truncatula FN6191 (mutant)</td>
			<td>In house</td>
			<td>FN6191</td>
			<td></td>
		</tr>
		<tr>
			<td>Medicago truncatula Jemalong A17 (reference)</td>
			<td>In house</td>
			<td>A17</td>
			<td></td>
		</tr>
		<tr>
			<td>Sulfuric acid</td>
			<td>Sigma-Aldrich</td>
			<td>320501</td>
			<td></td>
		</tr>
		<tr>
			<td>DNeasy Plant Mini Kit</td>
			<td>Qiagen</td>
			<td>69104</td>
			<td></td>
		</tr>
		<tr>
			<td>Nanodrop Spectrophotometer</td>
			<td>Thermo Scientific</td>
			<td>1000D</td>
			<td></td>
		</tr>
		<tr>
			<td>SureTag DNA Labeling Kit</td>
			<td>Agilent</td>
			<td>5190-3400</td>
			<td></td>
		</tr>
		<tr>
			<td>Random primer</td>
			<td>Agilent</td>
			<td>5190-3399</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetonitrile</td>
			<td>Sigma-Aldrich</td>
			<td>271004-1L</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocycler</td>
			<td>MJ research</td>
			<td>PTC-200</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Labnet international Inc</td>
			<td>Spectrafuge 24D</td>
			<td></td>
		</tr>
		<tr>
			<td>Stabilization and Drying Solution</td>
			<td>Agilent</td>
			<td>5185-5979</td>
			<td></td>
		</tr>
		<tr>
			<td>Oligo aCGH/ChIP-on-chip Hybridization Kit</td>
			<td>Agilent</td>
			<td>5188-5380</td>
			<td></td>
		</tr>
		<tr>
			<td>Hybridization Chamber gasket slides</td>
			<td>Agilent</td>
			<td>G2505</td>
			<td></td>
		</tr>
		<tr>
			<td>Human Cot-1 DNA</td>
			<td>Agilent</td>
			<td>5190-3393</td>
			<td></td>
		</tr>
		<tr>
			<td>Oligo aCGH/ChIP-on-chip Wash Buffer 1 and 2</td>
			<td>Agilent</td>
			<td>5188-5221</td>
			<td></td>
		</tr>
		<tr>
			<td>Hybridization Chamber, stainless</td>
			<td>Agilent</td>
			<td>G2534A</td>
			<td></td>
		</tr>
		<tr>
			<td>Hybridization oven</td>
			<td>Agilent</td>
			<td>G2545A</td>
			<td></td>
		</tr>
		<tr>
			<td>Purification Columns</td>
			<td>Agilent</td>
			<td>5190-3391</td>
			<td></td>
		</tr>
		<tr>
			<td>Laser scanner</td>
			<td>Roche</td>
			<td>MS200</td>
			<td></td>
		</tr>
		<tr>
			<td>NimbleScan 2.6</td>
			<td>Roche Nimblegen</td>
			<td>5225035001</td>
			<td></td>
		</tr>
		<tr>
			<td>Signal Map 1.9</td>
			<td>Roche Nimblegen</td>
			<td>Signalmap1.9</td>
			<td></td>
		</tr>
	</tbody>
</table>

an array-based comparative genomic hybridization platform for efficient detection of copy number variations in fast neutron-induced medicago truncatula mutants

Mutants are invaluable genetic resources for gene function studies. To generate mutant collections, three types of mutagens can be utilized, including biological such as T-DNA or transposon, chemical such as ethyl methanesulfonate (EMS), or physical such as ionization radiation. The type of mutation observed varies depending on the mutagen used. For ionization radiation induced mutants, mutations include deletion, duplication, or rearrangement. While T-DNA or transposon-based mutagenesis is limited to species that are susceptible to transformation, chemical or physical mutagenesis can be applied to a broad range of species. However, the characterization of mutations derived from chemical or physical mutagenesis traditionally relies on a map-based cloning approach, which is labor intensive and time consuming. Here, we show that a high-density genome array-based comparative genomic hybridization (aCGH) platform can be applied to efficiently detect and characterize copy number variations (CNVs) in mutants derived from fast neutron bombardment (FNB) mutagenesis in Medicago truncatula, a legume species. Whole genome sequence analysis shows that there are more than 50,000 genes or gene models in M. truncatula. At present, FNB-induced mutants in M. truncatula are derived from more than 150,000 M1 lines, representing invaluable genetic resources for functional studies of genes in the genome. The aCGH platform described here is an efficient tool for characterizing FNB-induced mutants in M. truncatula.

Figure 2 shows the distribution of normalized log2 ratios of mutant versus WT signals across the whole genome. Analysis of CGH data revealed an approximate 22 kb deletion on chromosome 4 that encompasses the entire SUNN gene33 and several other annotated genes in FN6191 mutant (Figure 2, Figure 3). The candidate deleted region was covered by 73 consecutive ...

Watch this Scientific Journal Video about An Array-based Comparative Genomic Hybridization Platform for Efficient Detection of Copy Number Variations in Fast Neutron-induced Medicago truncatula Mutant

An Array-based Comparative Genomic Hybridization Platform for Efficient Detection of Copy Number Variations in Fast Neutron-induced Medicago truncatula Mutants

This protocol provides experimental steps and information about reagents, equipment, and analysis tools for researchers who are interested in carrying out whole genome array-based comparative genomic hybridization (CGH) analysis of copy number variations in plants.

An Array-based Comparative Genomic Hybridization Platform for Efficient Detection of Copy Number Variations in Fast Neutron-induced Medicago truncatula Mutants

Mutants are invaluable genetic resources for gene function studies. To generate mutant collections, three types of mutagens can be utilized, including ...

The overall goal of this array-based comparative genomic hybridization protocol is to rapidly identify copy number variations in fast neutron bombardment induced mutants of the legume plant Medicago truncatula. This method helps to answer key questions in the field of legume biology. Such as, facilitating identification of empathogens on low site involved in regulating nodule development in legumes.The main advantage of this technique is that it is of highest repute and sensitive in detecting copy number variations such as deletion mutations in the neutron bombardment mutants of the legume plant Medicago truncatula. Demonstrating this procedure will be myself, and Hongcheng Wang, Host Doctor Fellows from Genetic Lab. Quickly freeze one gram of young leaf tissue collected from single plants in liquid nitrogen.Then, use a mortar and pestle and grind the frozen leaf tissue to fine powder within the liquid nitrogen. Extract the wild type and mutant genomic DNA samples from the fine powder using a DNA isolation kit. Use 500 microliter centrifuge tubes to dilute one microgram of each wild type and mutant genomic DNAs with double distilled water to a final volume of 20 microliters.Then, add five microliters of random primer to the centrifuge tubes. Quickly vortex the tubes, and after a quick spin down place them in a thermocycler for 10 minutes to denature the DNA samples at 98 degrees Celsius. After 10 minutes remove the tubes from the thermocycler, and instantly place them on ice water for five minutes.Then, prepare two labeling mixes and add 25 microliters of labeling mix as one and two to the wild type and mutant DNA tubes respectively. Pipette the DNA and the labeling mix three times, and then briefly spin the tubes. After spinning, incubate the tubes in the thermocycler at 37 degrees Celsius for two hours, and then at 65 degrees Celsius for 20 minutes to inactivate the exo Klenow enzyme.Then, add 430 microliters of One X TE Buffer, and mix the contents in each tube. Next, briefly spin the tubes and transfer the solution in the tubes to purification columns with two milliliter collection tubes. Centrifuge the purification columns at 14, 000 times G for 10 minutes and discard the flow through.Add 480 microliters of One X TE Buffer to each column, and again centrifuge at 14, 000 times G for 10 minutes. Discard the flow through. Transfer each of the wild type and mutant labeled DNAs from the bottom of the column to new centrifuge tubes.After measuring the volume of each of the labeled DNAs with the pipette adjust the final volume to 80 microliters with One X TE Buffer, then measure the concentration of the labeled DNAs in a spectrophotometer. Next, mix equivalent volumes of mutant and wild type DNAs to hybridize probes on a micro array chip for comparative hybridization. Bring the final volume to 160 microliters with One X TE Buffer.Next, prepare the hybridization solution and pipette it three times to mix three agents well with mixed DNA. After briefly spinning the tubes incubate them in a thermocycler at 98 degrees Celsius for 10 minutes, and at 37 degrees Celsius for 20 minutes. Remember to set the temperature to 67 degrees Celsius to preheat the hybridization oven four hours before hybridization.Then, place a gasket slide on the base of the hybridization chamber and load 490 microliters of the hybridization solution onto it after 20 minutes of incubation at 37 degrees Celsius in the thermocycler. To form the hybridization chamber cover the gasket slide with Medicago truncatula genome micro array chip, then cover the hybridization chamber and securely tighten it with the clamps. Incubate the assembled hybridization chamber in the hybridization oven at 67 degrees Celsius for 40 to 48 hours.Meanwhile, prepare two slide washing dishes with 250 milliliters of Washing Buffer One kept at room temperature. Then, make one slide washing dish with Washing Buffer Two kept at 37 degrees Celsius. Then, prepare one slide washing jar with 70 milliliters of acetonitrile, and another slide washing jar with 70 milliliters of stabilization and drawing solution.Place both the slide washing jars in a fume hood at room temperature. After incubation remove the hybridization chamber from the hybridization oven and loosen the chamber clamps to open the cover. Then, remove the micro array chip in the gasket slide and place them on slide washing dish with Wash Buffer One.Isolate the micro array chip from the cover slide. Next, transfer the micro array chip to the second slide washing dish with Wash Buffer One. Using a stir bar, gently stir the solution on a magnetic stir plate at room temperature for five minutes.Place the micro array chip on the slide washing dish with pre-warmed Washing Buffer Two, then stir with the stir bar to wash the solution at 37 degrees Celsius for one minute. Remove the micro array chip and place it in the acetonitrile containing slide washing jar in a fume hood to wash for 30 seconds. Transfer the micro array chip to the slide washing jar with stabilization and drying solution and wash again for 30 seconds.Carefully remove the chip and dry for one minute inside the fume hood. Scan the micro array chip using a scanner under two micrometer resolutions. A signal mapping software was used as an interface to analyze the distribution of normalized log two ratios of mutant versus wild type signals across eight chromosomes.For putative deletions value of log two ratio equal to or less than minus two point five standard deviation is considered. Segmentation analysis of the software demonstrates an estimated 22 kilobase deletion region on chromosome four shown in the graph. Analysis of the deletion borders flanked by the micro array probes show a reduced mean normalized log two ratio.The graph also shows six other annotated genes including the son gene encompassing the deleted region. Son gene is responsible for controlling nodulation in Metecago truncatula. Next, PCR amplification done to confirm the deletion borders shows a one point five kilobase product amplified from FN6191 mutant, but not in the wild type.DNA sequencing was done to show the deletion junction in FN6191 mutant shown in the black arrow. Sequencing was also done that confirmed the location of the deletion borders. Once mastered, this technique can be completed in 72 hours if it is performed properly.To obtain high quality data, remember to keep the ozone concentration low in the room where performing the procedure. Following this procedure, other measures such as polymerase chain reactions of all genome sequencing can be performed to answer additional questions like the size and the copy number variations in the genome. Event and validation of this technique has paved the way for researchers to explore copy number variation they induce to mutants and the natural variants in plant species that are not amenable to insertional mutagenesis such as Garden P.Don't forget that working with acetonitrile, stabilization and drying solution can be extremely hazardous.Precautions, such as wearing eye proctection, avoiding direct contact with the agents, and working careful is absolutely essential.

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The Visual Colorimetric Detection of Multi-nucleotide Polymorphisms on a Pneumatic Droplet Manipulation Platform

A simple and visual method to detect multi-nucleotide polymorphism (MNP) was performed on a pneumatic droplet manipulation platform on an open surface. This approach to colorimetric DNA detection was based on the hybridization-mediated growth of gold nanoparticle probes (AuNP probes). The growth size and configuration of the AuNP are dominated by the number of DNA samples hybridized with the probes. Based on the specific size- and shape-dependent optical properties of the nanoparticles, the number of mismatches in a sample DNA fragment to the probes is able to be discriminated. The tests were conducted via droplets containing reagents and DNA samples respectively, and were transported and mixed on the pneumatic platform with the controlled pneumatic suction of the flexible PDMS-based superhydrophobic membrane. Droplets can be delivered simultaneously and precisely on an open-surface on the proposed pneumatic platform that is highly biocompatible with no side effect of DNA samples inside the droplets. Combining the two proposed methods, the multi-nucleotide polymorphism can be detected at sight on the pneumatic droplet manipulation platform; no additional instrument is required. The procedure from installing the droplets on the platform to the final result takes less than 5 min, much less than with existing methods. Moreover, this combined MNP detection approach requires a sample volume of only 10 &#181;l in each operation, which is remarkably less than that of a macro system.

This work presents a simple and visual method to detect multi-nucleotide polymorphisms on a pneumatic droplet manipulation platform. With the proposed method, the entire experiment, including droplet manipulation and detection of multi-nucleotide polymorphisms, can be performed near 23 &#176;C without the aid of advanced instruments.

A simple and visual method to detect multi-nucleotide polymorphism (MNP) was performed on a pneumatic droplet manipulation platform on an open surface. ...

Leveraging CyVerse Resources for De Novo Comparative Transcriptomics of Underserved (Non-model) Organisms

This workflow allows novice researchers to leverage advanced computational resources such as cloud computing to carry out pairwise comparative transcriptomics. It also serves as a primer for biologists to develop data scientist computational skills, e.g. executing bash commands, visualization and management of large data sets. All command line code and further explanations of each command or step can be found on the wiki (<a href="https://wiki.cyverse.org/wiki/x/dgGtAQ">https://wiki.cyverse.org/wiki/x/dgGtAQ</a>). The Discovery Environment and Atmosphere platforms are connected together through the CyVerse Data Store. As such, once the initial raw sequencing data has been uploaded there is no more need to transfer large data files over an Internet connection, minimizing the amount of time needed to conduct analyses. This protocol is designed to analyze only two experimental treatments or conditions. Differential gene expression analysis is conducted through pairwise comparisons, and will not be suitable to test multiple factors. This workflow is also designed to be manual rather than automated. Each step must be executed and investigated by the user, yielding a better understanding of data and analytical outputs, and therefore better results for the user. Once complete, this protocol will yield de novo assembled transcriptome(s) for underserved (non-model) organisms without the need to map to previously assembled reference genomes (which are usually not available in underserved organism). These de novo transcriptomes are further used in pairwise differential gene expression analysis to investigate genes differing between two experimental conditions. Differentially expressed genes are then functionally annotated to understand the genetic response organisms have to experimental conditions. In total, the data derived from this protocol is used to test hypotheses about biological responses of underserved organisms.

Leveraging CyVerse Resources for De Novo Comparative Transcriptomics of Underserved Non-model Organisms

This protocol outlines a comparative de novo transcriptome assembly and annotation workflow for novice bioinformaticians. The workflow is available for free entirely through CyVerse and connected by the Data Store. Command line and graphical user interfaces are used, but all code needed is available to copy and paste.

This workflow allows novice researchers to leverage advanced computational resources such as cloud computing to carry out pairwise comparative ...

Detection of Copy Number Alterations Using Single Cell Sequencing

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and microbial populations. Traditional methods for assessing genetic heterogeneity have been limited by low resolution, low sensitivity, and/or low specificity. Single cell sequencing has emerged as a powerful tool for detecting genetic heterogeneity with high resolution, high sensitivity and, when appropriately analyzed, high specificity. Here we provide a protocol for the isolation, whole genome amplification, sequencing, and analysis of single cells. Our approach allows for the reliable identification of megabase-scale copy number variants in single cells. However, aspects of this protocol can also be applied to investigate other types of genetic alterations in single cells.

Single cell sequencing is an increasingly popular and accessible tool for addressing genomic changes at high resolution. We provide a protocol that uses single cell sequencing to identify copy number alterations in single cells.

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and ...

Detection of Inter-chromosomal Stable Aberrations by Multiple Fluorescence In Situ Hybridization (mFISH) and Spectral Karyotyping (SKY) in Irradiated Mice

Ionizing radiation (IR) induces numerous stable and unstable chromosomal aberrations. Unstable aberrations, where chromosome morphology is substantially compromised, can easily be identified by conventional chromosome staining techniques. However, detection of stable aberrations, which involve exchange or translocation of genetic materials without considerable modification in the chromosome morphology, requires sophisticated chromosome painting techniques that rely on in situ hybridization of fluorescently labeled DNA probes, a chromosome painting technique popularly known as fluorescence in situ hybridization (FISH). FISH probes can be specific for whole chromosome/s or precise sub-region on chromosome/s. The method not only allows visualization of stable aberrations, but it can also allow detection of the chromosome/s or specific DNA sequence/s involved in a particular aberration formation. A variety of chromosome painting techniques are available in cytogenetics; here two highly sensitive methods, multiple fluorescence in situ hybridization (mFISH) and spectral karyotyping (SKY), are discussed to identify inter-chromosomal stable aberrations that form in the bone marrow cells of mice after exposure to total body irradiation. Although both techniques rely on fluorescent labeled DNA probes, the method of detection and the process of image acquisition of the fluorescent signals are different. These two techniques have been used in various research areas, such as radiation biology, cancer cytogenetics, retrospective radiation biodosimetry, clinical cytogenetics, evolutionary cytogenetics, and comparative cytogenetics.

Detection of Inter-chromosomal Stable Aberrations by Multiple Fluorescence In Situ Hybridization mFISH and Spectral Karyotyping SKY in Irradiated Mice

The present protocol describes the usefulness of multiple fluorescence in situ hybridization (mFISH) and spectral karyotyping (SKY) in identifying inter-chromosomal stable aberrations in the bone marrow cells of mice after exposure to total body irradiation.

Ionizing radiation (IR) induces numerous stable and unstable chromosomal aberrations. Unstable aberrations, where chromosome morphology is substantially ...

A Fast Silver Staining Protocol Enabling Simple and Efficient Detection of SSR Markers using a Non-denaturing Polyacrylamide Gel

Simple Sequence Repeat (SSR) is one of the most effective markers used in plant and animal genetic research and molecular breeding programs. Silver staining is a widely used method for the detection of SSR markers in a polyacrylamide gel. However, conventional protocols for silver staining are technically demanding and time-consuming. Like many other biological laboratory techniques, silver staining protocols have been steadily optimized to improve detection efficiency. Here, we report a simplified silver staining method that significantly reduces reagent costs and enhances the detection resolution and picture clarity. The new method requires two major steps (impregnation and development) and three reagents (silver nitrate, sodium hydroxide, and formaldehyde), and only 7 min of processing for a non-denaturing polyacrylamide gel. Compared to previously reported protocols, this new method is easier, quicker and uses fewer chemical reagents for SSR detection. Therefore, this simple, low-cost, and effective silver staining protocol will benefit genetic mapping and marker-assisted breeding by a quick generation of SSR marker data.

Here, we report a simple and low-cost silver staining protocol which requires only three reagents and 7 min of processing, and is suitable for fast generation of high-quality SSR data in the genetic analysis.

Simple Sequence Repeat (SSR) is one of the most effective markers used in plant and animal genetic research and molecular breeding programs. Silver ...

Generating Transgenic Plants with Single-copy Insertions Using BIBAC-GW Binary Vector

When generating transgenic plants, generally the objective is to have stable expression of a transgene. This requires a single, intact integration of the transgene, as multi-copy integrations are often subjected to gene silencing. The Gateway-compatible binary vector based on bacterial artificial chromosomes (pBIBAC-GW), like other pBIBAC derivatives, allows the insertion of single-copy transgenes with high efficiency. As an improvement to the original pBIBAC, a Gateway cassette has been cloned into pBIBAC-GW, so that the sequences of interest can now be easily incorporated into the vector transfer DNA (T-DNA) by Gateway cloning. Commonly, the transformation with pBIBAC-GW results in an efficiency of 0.2&#8211;0.5%, whereby half of the transgenics carry an intact single-copy integration of the T-DNA. The pBIBAC-GW vectors are available with resistance to Glufosinate-ammonium or DsRed fluorescence in seed coats for selection in plants, and with resistance to kanamycin as a selection in bacteria. Here, a series of protocols is presented that guide the reader through the process of generating transgenic plants using pBIBAC-GW: starting from recombining the sequences of interest into the pBIBAC-GW vector of choice, to plant transformation with Agrobacterium, selection of the transgenics, and testing the plants for intactness and copy number of the inserts using DNA blotting. Attention is given to designing a DNA blotting strategy to recognize single- and multi-copy integrations at single and multiple loci.

Using a pBIBAC-GW binary vector makes generating transgenic plants with intact single-copy insertions, an easy process. Here, a series of protocols is presented that guide the reader through the process of generating transgenic Arabidopsis plants, and testing the plants for intactness and copy number of the inserts.

When generating transgenic plants, generally the objective is to have stable expression of a transgene. This requires a single, intact integration of the ...

CRISPR-Mediated Reorganization of Chromatin Loop Structure

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene expression, but whether looping is responsible for or a result of alterations in gene expression is still unknown. Until recently, how chromatin looping affects the regulation of gene activity and cellular function has been relatively ambiguous, and limitations in existing methods to manipulate these structures prevented in-depth exploration of these interactions. To resolve this uncertainty, we engineered a method for selective and reversible chromatin loop re-organization using CRISPR-dCas9 (CLOuD9). The dynamism of the CLOuD9 system has been demonstrated by successful localization of CLOuD9 constructs to target genomic loci to modulate local chromatin conformation. Importantly, the ability to reverse the induced contact and restore the endogenous chromatin conformation has also been confirmed. Modulation of gene expression with this method establishes the capacity to regulate cellular gene expression and underscores the great potential for applications of this technology in creating stable de novo chromatin loops that markedly affect gene expression in the contexts of cancer and development.

Chromatin looping plays a significant role in gene regulation; however, there have been no technological advances that allow for selective and reversible modification of chromatin loops. Here we describe a powerful system for chromatin loop re-organization using CRISPR-dCas9 (CLOuD9), demonstrated to selectively and reversibly modulate gene expression at targeted loci.

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene ...

A Rapid and Facile Pipeline for Generating Genomic Point Mutants in C. elegans Using CRISPR/Cas9 Ribonucleoproteins

The clustered regularly interspersed palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) prokaryotic adaptive immune defense system has been co-opted as a powerful tool for precise eukaryotic genome engineering. Here, we present a rapid and simple method using chimeric single guide RNAs (sgRNA) and CRISPR-Cas9 Ribonucleoproteins (RNPs) for the efficient and precise generation of genomic point mutations in C. elegans. We describe a pipeline for sgRNA target selection, homology-directed repair (HDR) template design, CRISPR-Cas9-RNP complexing and delivery, and a genotyping strategy that enables the robust and rapid identification of correctly edited animals. Our approach not only permits the facile generation and identification of desired genomic point mutant animals, but also facilitates the detection of other complex indel alleles in approximately 4 - 5 days with high efficiency and a reduced screening workload.

A Rapid and Facile Pipeline for Generating Genomic Point Mutants in C. elegans Using CRISPR/Cas9 Ribonucleoproteins

Here, we present a method to engineer the genome of C. elegans using CRISPR-Cas9 ribonucleoproteins and homology dependent repair templates.

The clustered regularly interspersed palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) prokaryotic adaptive immune defense system has been ...

CRISPR/Cas9 Gene Editing to Make Conditional Mutants of Human Malaria Parasite P. falciparum

Malaria is a significant cause of morbidity and mortality worldwide. This disease, which primarily affects those living in tropical and subtropical regions, is caused by infection with Plasmodium parasites. The development of more effective drugs to combat malaria can be accelerated by improving our understanding of the biology of this complex parasite. Genetic manipulation of these parasites is key to understanding their biology; however, historically the genome of P. falciparum has been difficult to manipulate. Recently, CRISPR/Cas9 genome editing has been utilized in malaria parasites, allowing for easier protein tagging, generation of conditional protein knockdowns, and deletion of genes. CRISPR/Cas9 genome editing has proven to be a powerful tool for advancing the field of malaria research. Here, we describe a CRISPR/Cas9 method for generating glmS-based conditional knockdown mutants in P. falciparum. This method is highly adaptable to other types of genetic manipulations, including protein tagging and gene knockouts.

CRISPR/Cas9 Gene Editing to Make Conditional Mutants of Human Malaria Parasite P. falciparum

We describe a method for generating glmS-based conditional knockdown mutants in Plasmodium falciparum using CRISPR/Cas9 genome editing.

Malaria is a significant cause of morbidity and mortality worldwide. This disease, which primarily affects those living in tropical and subtropical ...

Visualization of Microbiota in Tick Guts by Whole-mount In Situ Hybridization

Infectious diseases transmitted by arthropod vectors continue to pose a significant threat to human health worldwide. The pathogens causing these diseases, do not exist in isolation when they colonize the vector; rather, they likely engage in interactions with resident microorganisms in the gut lumen. The vector microbiota has been demonstrated to play an important role in pathogen transmission for several vector-borne diseases. Whether resident bacteria in the gut of the Ixodes scapularis tick, the vector of several human pathogens including Borrelia burgdorferi, influence tick transmission of pathogens is not determined. We require methods for characterizing the composition of the bacteria associated with the tick gut to facilitate a better understanding of potential interspecies interactions in the tick gut. Using whole-mount in situ hybridization to visualize RNA transcripts associated with particular bacterial species allows for the collection of qualitative data regarding the abundance and distribution of the microbiota in intact tissue. This technique can be used to examine changes in the gut microbiota milieu over the course of tick feeding and can also be applied to analyze expression of tick genes. Staining of whole tick guts yield information about the gross spatial distribution of target RNA in the tissue without the need for three-dimensional reconstruction and is less affected by environmental contamination, which often confounds the sequencing-based methods frequently used to study complex microbial communities. Overall, this technique is a valuable tool that can be used to better understand vector-pathogen-microbiota interactions and their role in disease transmission.

Visualization of Microbiota in Tick Guts by Whole-mount In Situ Hybridization

Here, we present a protocol to spatially and temporally assess the presence of viable microbiota in tick guts using a modified whole-mount in situ hybridization approach.