This study was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A3B03035662); and Hallym University Research Fund, 2017 (HRF-201703-003).

<ol>
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The authors have nothing to disclose.

Strategies for the determination of bona fide miRNA targets with the functions of a miRNA of interest are indispensable for the understanding of multiple roles of miRNAs. Identification of miRNA target genes can be a guideline for interpreting the cell signaling events modulated by miRNAs in a cell. An unveiling of functionally important target genes of miRNAs can provide the fundamental knowledge to develop a miRNA-based therapy in cancer.
Several methods such as microarrays, small RNA librar...

MicroRNAs (miRNAs) are the small regulatory RNAs that mainly modulate the process of translation and degradation of messenger RNAs (mRNAs) by reacting to the 3&#8217; untranslated regions (3&#8217; UTR) in bona fide target genes1. Expression of miRNAs can be regulated by transcriptional and post-transcriptional mechanisms. The imbalance of such regulatory mechanisms brings uncontrolled and distinctive miRNAs expression levels in numerous diseases including cancers2. A single miRNA can have multiple interactions with diverse mRNAs. Correspondingly, an individual mRNA can be controlled by various miRNAs. Therefore, intracellular signaling networks are intricately influenced by distinctively expressed miRNAs by which physiological disorders and diseases can be initiated and deteriorated2,3,4,5,6. Although the altered expression of miRNAs has been observed in various types of cancers, the molecular mechanisms that modulate the manners of cancer cells in conjunction with miRNAs are still largely unknown.
Accumulating evidence has been showing that the oncogenic or tumor-suppressive roles of miRNAs depend on the types of cancers. For example, by targeting forkhead box o3 (FOXO3), miR-155 promotes the cell proliferation, metastasis, and chemoresistance of colorectal cancer7,8. In contrast, the restriction of glioma cell invasion is induced by miR-107 via the regulation of neurogenic locus notch homolog protein 2 (NOTCH2) expression9. The assessment of miRNA-target interactions in connection with miRNA functions is an indispensable part to better understand how miRNAs regulate various biological processes in both healthy and diseased states10. In addition, the discovery of bona fide target(s) of miRNAs can further provide a fine-tuned strategy for a miRNA-based therapy with various anti-cancer drugs. However, the main challenge in the field of miRNAs is the identification of direct targets of miRNAs. Here, detailed methods are presented as reproducible experimental approaches for the miRNA target gene determination. Successful experimental design for the miRNA target identification involves various steps and considerations (Figure 1). Comparison of mature miRNA levels in tumor cells and normal cells can be one of the common procedures to select a miRNA of interest (Figure 1A). The functional study of a selected miRNA to detect the effects of a miRNA on cell proliferation is important to narrow down the list of best potential candidate targets of a miRNA of interest (Figure 1B). Based on the experimentally validated functions of miRNAs, a systematic review of literature and database in company with a miRNA target prediction program is required to search the most relevant information on gene functions (Figure 1C). The identification of real target genes of a miRNA of interest can be achieved by implementing experiments such as the luciferase assay along with the cloning of 3&#8217; UTR of a gene, real-time PCR, and western blotting (Figure 1D). The goal of the current protocol is to provide comprehensive methods of key experiments, the probe-based real-time polymerase chain reaction (PCR), sulforhodamine B (SRB) assay following a miRNA mimic transfection, dose-response curve generation, and luciferase assay along with the cloning of 3&#8217; UTR of a gene. The current protocol can be useful for a better understanding of the functions of individual miRNAs and the implication of a miRNA in cancer therapy.

<table>
	<tbody>
		<tr>
			<td>15 mL conical tube</td>
			<td>SPL Life Sciences</td>
			<td>50015</td>
			<td></td>
		</tr>
		<tr>
			<td>24-well plate</td>
			<td>Thermo Scientific</td>
			<td>142475</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL conical tube</td>
			<td>SPL Life Sciences</td>
			<td>50050</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well plate</td>
			<td>Falcon</td>
			<td>353046</td>
			<td></td>
		</tr>
		<tr>
			<td>6X DNA loading dye</td>
			<td>Real Biotech Corporation</td>
			<td>RD006</td>
			<td>1 mL</td>
		</tr>
		<tr>
			<td>8-cap strip</td>
			<td>Applied Biosystems</td>
			<td>N8010535</td>
			<td>For cDNA synthesis</td>
		</tr>
		<tr>
			<td>8-tube strip</td>
			<td>Applied Biosystems</td>
			<td>N8010580</td>
			<td>For cDNA synthesis</td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>Falcon</td>
			<td>353072</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Sigma</td>
			<td>A6283-1L</td>
			<td>1 L</td>
		</tr>
		<tr>
			<td>Agarose A</td>
			<td>Bio Basic</td>
			<td>D0012</td>
			<td>500 g</td>
		</tr>
		<tr>
			<td>Alkaline phosphatase</td>
			<td>New England Biolabs</td>
			<td>M0290S</td>
			<td>10,000 U/mL</td>
		</tr>
		<tr>
			<td>Ampicillin</td>
			<td>Bio basic Canada Inc</td>
			<td>AB0028</td>
			<td>25 g</td>
		</tr>
		<tr>
			<td>AriaMx 96 tube strips</td>
			<td>Agilent Technologies</td>
			<td>401493</td>
			<td>For real time PCR</td>
		</tr>
		<tr>
			<td>AriaMx real-time PCR system</td>
			<td>Agilent Technologies</td>
			<td>G8830A</td>
			<td>qPCR amplification, detection, and data analysis</td>
		</tr>
		<tr>
			<td>AsiSI</td>
			<td>New England Biolabs</td>
			<td>R0630</td>
			<td>10,000 units/mL</td>
		</tr>
		<tr>
			<td>CAPAN-1 cells</td>
			<td>ATCC</td>
			<td>HTB-79</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture hood</td>
			<td>Labtech</td>
			<td></td>
			<td>Model: LCB-1203B-A2</td>
		</tr>
		<tr>
			<td>Counting chambers with V-slash</td>
			<td>Paul Marienfeld</td>
			<td>650010</td>
			<td>Cells counter</td>
		</tr>
		<tr>
			<td>CutSmart buffer</td>
			<td>New England Biolabs</td>
			<td>B7204S</td>
			<td>10X concentration</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Gibco</td>
			<td>11965-092</td>
			<td>500 mL</td>
		</tr>
		<tr>
			<td>DNA gel extraction kit</td>
			<td>Bionics</td>
			<td>DN30200</td>
			<td>200 prep</td>
		</tr>
		<tr>
			<td>DNA ladder</td>
			<td>NIPPON Genetics EUROPE</td>
			<td>MWD1</td>
			<td>1 Kb ladder</td>
		</tr>
		<tr>
			<td>DNase I</td>
			<td>Invitrogen</td>
			<td>18068015</td>
			<td>100 units</td>
		</tr>
		<tr>
			<td>Dual-luciferase reporter assay system</td>
			<td>Promega</td>
			<td>E1910</td>
			<td>100 assays</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Gibco</td>
			<td>26140-079</td>
			<td>500 mL</td>
		</tr>
		<tr>
			<td>HIT competent cells</td>
			<td>Real Biotech Corporation(RBC)</td>
			<td>RH617</td>
			<td>Competent cells</td>
		</tr>
		<tr>
			<td>HPNE cells</td>
			<td>ATCC</td>
			<td>CRL-4023</td>
			<td></td>
		</tr>
		<tr>
			<td>LB agar broth</td>
			<td>Bio Basic</td>
			<td>SD7003</td>
			<td>250 g</td>
		</tr>
		<tr>
			<td>Lipofectamine 2000</td>
			<td>Invitrogen</td>
			<td>11668-027</td>
			<td>0.75 mL</td>
		</tr>
		<tr>
			<td>Lipofectamine RNAiMax</td>
			<td>Invitrogen</td>
			<td>13778-075</td>
			<td>0.75 mL</td>
		</tr>
		<tr>
			<td>Luminometer</td>
			<td>Promega</td>
			<td></td>
			<td>Model: E5311</td>
		</tr>
		<tr>
			<td>Microcentrifuge tube</td>
			<td>Eppendorf</td>
			<td>22431021</td>
			<td></td>
		</tr>
		<tr>
			<td>Microplate reader</td>
			<td>TECAN</td>
			<td></td>
			<td>Infinite F50</td>
		</tr>
		<tr>
			<td>miRNA control mimic</td>
			<td>Ambion</td>
			<td>4464058</td>
			<td>5 nmole</td>
		</tr>
		<tr>
			<td>miRNA-107 mimic</td>
			<td>Ambion</td>
			<td>4464066</td>
			<td>5 nmole</td>
		</tr>
		<tr>
			<td>miRNeasy Mini Kit</td>
			<td>Qiagen</td>
			<td>217004</td>
			<td>50 prep</td>
		</tr>
		<tr>
			<td>Mupid-2plus (electrophoresis system)</td>
			<td>TaKaRa</td>
			<td></td>
			<td>Model: AD110</td>
		</tr>
		<tr>
			<td>NotI</td>
			<td>New England Biolabs</td>
			<td>R3189</td>
			<td>20,000 units/mL</td>
		</tr>
		<tr>
			<td>Oligo explorer program</td>
			<td>GeneLink</td>
			<td></td>
			<td>For primer design</td>
		</tr>
		<tr>
			<td>Optical tube strip caps (8X Strip)</td>
			<td>Agilent Technologies</td>
			<td>401425</td>
			<td>For real time PCR</td>
		</tr>
		<tr>
			<td>Opti-MEM</td>
			<td>Gibco</td>
			<td>31985-070</td>
			<td>500 Ml</td>
		</tr>
		<tr>
			<td>PANC-1 cells</td>
			<td>ATCC</td>
			<td>CRL-1469</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>100 mL</td>
		</tr>
		<tr>
			<td>Phosphate buffer saline</td>
			<td>Gibco</td>
			<td>14040117</td>
			<td>1000 mL</td>
		</tr>
		<tr>
			<td>Plasmid DNA miniprep S&#38; V kit</td>
			<td>Bionics</td>
			<td>DN10200</td>
			<td>200 prep</td>
		</tr>
		<tr>
			<td>PrimeSTAR GXL DNA polymerase</td>
			<td>TaKaRa</td>
			<td>R050A</td>
			<td>250 units</td>
		</tr>
		<tr>
			<td>Shaker</td>
			<td>TECAN</td>
			<td></td>
			<td>Shaking platform</td>
		</tr>
		<tr>
			<td>Shaking incubator</td>
			<td>Labtech</td>
			<td></td>
			<td>Model: LSI-3016A</td>
		</tr>
		<tr>
			<td>Sigmaplot 14 software</td>
			<td>Systat Software Inc</td>
			<td></td>
			<td>For dose-response curve generation</td>
		</tr>
		<tr>
			<td>Sulforhodamine B powder</td>
			<td>Sigma</td>
			<td>S1402-5G</td>
			<td>5 g</td>
		</tr>
		<tr>
			<td>SYBR green master mix</td>
			<td>Smobio</td>
			<td>TQ12001805401-3</td>
			<td>Binding fluorescent dye for dsDNA</td>
		</tr>
		<tr>
			<td>T4 DNA ligase</td>
			<td>TaKaRa</td>
			<td>2011A</td>
			<td>25,000 U</td>
		</tr>
		<tr>
			<td>TaqMan master mix</td>
			<td>Applied Biosystems</td>
			<td>4324018</td>
			<td>200 reactions, no AmpErase UNG</td>
		</tr>
		<tr>
			<td>TaqMan microRNA assay (hsa-miR-107)</td>
			<td>Applied Biosystems</td>
			<td>4427975</td>
			<td>Assay ID: 000443 (50RT, 150 PCR rxns)</td>
		</tr>
		<tr>
			<td>TaqMan microRNA assay (hsa-miR-301)</td>
			<td>Applied Biosystems</td>
			<td>4427975</td>
			<td>Assay ID: 000528 (50RT, 150 PCR rxns)</td>
		</tr>
		<tr>
			<td>TaqMan miR RT kit</td>
			<td>Applied Biosystems</td>
			<td>4366597</td>
			<td>1000 reactions</td>
		</tr>
		<tr>
			<td>Thermo CO2 incubator (BB15)</td>
			<td>ThermoFisher Scientific</td>
			<td></td>
			<td>37 &#176;C and 5% CO2 incubation</td>
		</tr>
		<tr>
			<td>Trichloroacetic acid</td>
			<td>Sigma</td>
			<td>91228-100G</td>
			<td>100 g</td>
		</tr>
		<tr>
			<td>Trizma base</td>
			<td>Sigma</td>
			<td>T4661-100G</td>
			<td>100 g</td>
		</tr>
		<tr>
			<td>Ultrapure water</td>
			<td>Invitrogen</td>
			<td>10977-015</td>
			<td>500 mL</td>
		</tr>
		<tr>
			<td>Veriti 96 well thermal cycler</td>
			<td>Applied Biosystems</td>
			<td></td>
			<td>For amplification of DNA (or cDNA)</td>
		</tr>
		<tr>
			<td>XhoI</td>
			<td>New England Biolabs</td>
			<td>R0146</td>
			<td>20,000 units/mL</td>
		</tr>
	</tbody>
</table>

an in vitro protocol for evaluating microrna levels, functions, and associated target genes in tumor cells

MicroRNAs (miRNAs) are small regulatory RNAs which are recognized to modulate numerous intracellular signaling pathways in several diseases including cancers. These small regulatory RNAs mainly interact with the 3&#8217; untranslated regions (3&#8217; UTR) of their target messenger RNAs (mRNAs) ultimately resulting in the inhibition of decoding processes of mRNAs and the augmentation of target mRNA degradations. Based on the expression levels and intracellular functions, miRNAs are able to serve as regulatory factors of oncogenic and tumor-suppressive mRNAs. Identification of bona fide target genes of a miRNA among hundreds or even thousands of computationally predicted targets is a crucial step to discern the roles and basic molecular mechanisms of a miRNA of interest. Various miRNA target prediction programs are available to search possible miRNA-mRNA interactions. However, the most challenging question is how to validate direct target genes of a miRNA of interest. This protocol describes a reproducible strategy of key methods on how to identify miRNA targets related to the function of a miRNA. This protocol presents a practical guide on step-by-step procedures to uncover miRNA levels, functions, and related target mRNAs using the probe-based real-time polymerase chain reaction (PCR), sulforhodamine B (SRB) assay following a miRNA mimic transfection, dose-response curve generation, and luciferase assay along with the cloning of 3&#8217; UTR of a gene, which is necessary for proper understanding of the roles of individual miRNAs.

Successful and accurate confirmation of miRNA levels is important for the interpretation of data by which the classification of miRNAs is possible based on the anticipated roles of miRNAs in the development and progression of a disease. The levels of miRNA-107 and miRNA-301 were measured in three pancreas cell lines using the probe-based quantitative PCR. The synthesis of cDNAs of both a specific miRNA and a reference gene in the same reaction can increase the reproducibility of data. PANC-1 and CAPAN-1 are human pancrea...

Watch this Scientific Journal Video about An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells at JoVE.com

An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells

This protocol uses a probe-based real-time polymerase chain reaction (PCR), a sulforhodamine B (SRB) assay, 3&#8217; untranslated regions (3&#8217; UTR) cloning, and a luciferase assay to verify the target genes of a miRNA of interest and to understand the functions of miRNAs.

MicroRNAs (miRNAs) are small regulatory RNAs which are recognized to modulate numerous intracellular signaling pathways in several diseases including ...

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Genetics

8.2K Views.  Hallym University. This protocol uses a probe-based real-time polymerase chain reaction (PCR), a sulforhodamine B (SRB) assay, 3’ untranslated regions (3’ UTR) cloning, and a luciferase assay to verify the target genes of a miRNA of interest and to understand the functions of miRNAs.

Video: An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells

Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System

Exposure to particulate matter (PM) is a major world health concern, which may damage various cellular components, including the nuclear genetic material. To assess the impact of PM on nuclear genetic integrity, structural chromosomal aberrations are scored in the metaphase spreads of mouse RAW264.7 macrophage cells. PM is collected from ambient air with a high volume total suspended particles sampler. The collected material is solubilized and filtered to retain the water-soluble, fine portion. The particles are characterized for chemical composition by nuclear magnetic resonance (NMR) spectroscopy. Different concentrations of particle suspension are added onto an in vitro culture of RAW264.7 mouse macrophages for a total exposure time of 72 hr, along with untreated control cells. At the end of exposure, the culture is treated with colcemid to arrest cells in metaphase. Cells are then harvested, treated with hypotonic solution, fixed in acetomethanol, dropped onto glass slides and finally stained with Giemsa solution. Slides are examined to assess the structural chromosomal aberrations (CAs) in metaphase spreads at 1,000X magnification using a bright-field microscope. 50 to 100 metaphase spread are scored for each treatment group. This technique is adapted for the detection of structural chromosomal aberrations (CAs), such as chromatid-type breaks, chromatid-type exchanges, acentric fragments, dicentric and ring chromosomes, double minutes, endoreduplication, and Robertsonian translocations in vitro after exposure to PM. It is a powerful method to associate a well-established cytogenetic endpoint to epigenetic alterations.

Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System

This protocol describes techniques for the quantification and characterization of chromosomal aberrations in vitro in RAW264.7 mouse macrophages after treatment with ambient air particulate matter.

Exposure to particulate matter (PM) is a major world health concern, which may damage various cellular components, including the nuclear genetic material. ...

Peptide-derived Method to Transport Genes and Proteins Across Cellular and Organellar Barriers in Plants

The capacity to introduce exogenous proteins and express (or down-regulate) specific genes in plants provides a powerful tool for fundamental research as well as new applications in the field of plant biotechnology. Viable methods that currently exist for protein or gene transfer into plant cells, namely Agrobacterium and microprojectile bombardment, have disadvantages of low transformation frequency, limited host range, or a high cost of equipment and microcarriers. The following protocol outlines a simple and versatile method, which employs rationally-designed peptides as delivery agents for a variety of nucleic acid- and protein-based cargoes into plants. Peptides are selected as tools for development of the system due to their biodegradability, reduced size, diverse and tunable properties as well as the ability to gain intracellular/organellar access. The preparation, characterization and application of optimized formulations for each type of the wide range of delivered cargoes (plasmid DNA, double-stranded DNA or RNA, and protein) are described. Critical steps within the protocol, possible modifications and existing limitations of the method are also discussed.

Existing methods for the modification of plants have limited applicability. The novel peptide-derived technology proposed here promises both simplicity and efficiency in the introduction of exogenous protein or genes into the desired intracellular compartments of intact plants.

The capacity to introduce exogenous proteins and express (or down-regulate) specific genes in plants provides a powerful tool for fundamental research as ...

Systemic Delivery of MicroRNA Using Recombinant Adeno-associated Virus Serotype 9 to Treat Neuromuscular Diseases in Rodents

RNA interference via the endogenous miRNA pathway regulates gene expression by controlling protein synthesis through post-transcriptional gene silencing. In recent years, miRNA-mediated gene regulation has shown potential for treatment of neurological disorders caused by a toxic gain of function mechanism. However, efficient delivery to target tissues has limited its application. Here we used a transgenic mouse model for spinal and bulbar muscular atrophy (SBMA), a neuromuscular disease caused by polyglutamine expansion in the androgen receptor (AR), to test gene silencing by a newly identified AR-targeting miRNA, miR-298. We overexpressed miR-298 using a recombinant adeno-associated virus (rAAV) serotype 9 vector to facilitate transduction of non-dividing cells. A single tail-vein injection in SBMA mice induced sustained and widespread overexpression of miR-298 in skeletal muscle and motor neurons and resulted in amelioration of the neuromuscular phenotype in the mice.

Here we describe the delivery of microRNA using a recombinant adeno-associated virus serotype 9 in a mouse model of a neuromuscular disease. A single peripheral administration in mice resulted in sustained miRNA overexpression in muscle and motor neurons, providing an opportunity to study miRNA function and therapeutic potential in vivo.

RNA interference via the endogenous miRNA pathway regulates gene expression by controlling protein synthesis through post-transcriptional gene silencing. ...

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

The circadian rhythm is a fundamental physiological process present in all organisms that regulates biological processes ranging from gene expression to sleep behavior. In vertebrates, circadian rhythm is controlled by a molecular oscillator that functions in both the suprachiasmatic nucleus (SCN; central pacemaker) and individual cells comprising most peripheral tissues. More importantly, disruption of circadian rhythm by exposure to light-at-night, environmental stressors and/or toxicants is associated with increased risk of chronic diseases and aging. The ability to identify agents that can disrupt central and/or peripheral biological clocks, and agents that can prevent or mitigate the effects of circadian disruption, has significant implications for prevention of chronic diseases. Although rodent models can be used to identify exposures and agents that induce or prevent/mitigate circadian disruption, these experiments require large numbers of animals. In vivo studies also require significant resources and infrastructure, and require researchers to work all night. Thus, there is an urgent need for a cell-type appropriate in vitro system to screen for environmental circadian disruptors and enhancers in cell types from different organs and disease states. We constructed a vector that drives transcription of the destabilized luciferase in eukaryotic cells under the control of the human PERIOD 2 gene promoter. This circadian reporter construct was stably transfected into human mammary epithelial cells, and circadian responsive reporter cells were selected to develop the in vitro bioluminescence assay. Here, we present a detailed protocol to establish and validate the assay. We further provide details for proof of concept experiments demonstrating the ability of our in vitro assay to recapitulate the in vivo effects of various chemicals on the cellular biological clock. The results indicate that the assay can be adapted to a variety of cell types to screen for both environmental disruptors and chemopreventive enhancers of circadian clocks.

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

An in vitro bioluminescence assay to determine cellular circadian rhythm in mammary epithelial cells is presented. This method utilizes mammalian cell reporter plasmids expressing destabilized luciferase under the control of the PERIOD 2 gene promoter. It can be adapted to other cell types to evaluate organ-specific effects on circadian rhythm.

The circadian rhythm is a fundamental physiological process present in all organisms that regulates biological processes ranging from gene expression to ...

Chromatin Immunoprecipitation (ChIP) Protocol for Low-abundance Embryonic Samples

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, transcription factors, or chromatin-modifying enzymes at a given locus or on a genome-wide scale. The combination of ChIP assays with next-generation sequencing (i.e., ChIP-Seq) is a powerful approach to globally uncover gene regulatory networks and to improve the functional annotation of genomes, especially of non-coding regulatory sequences. ChIP protocols normally require large amounts of cellular material, thus precluding the applicability of this method to investigating rare cell types or small tissue biopsies. In order to make the ChIP assay compatible with the amount of biological material that can typically be obtained in vivo during early vertebrate embryogenesis, we describe here a simplified ChIP protocol in which the number of steps required to complete the assay were reduced to minimize sample loss. This ChIP protocol has been successfully used to investigate different histone modifications in various embryonic chicken and adult mouse tissues using low to medium cell numbers (5 x 104 - 5 x 105 cells). Importantly, this protocol is compatible with ChIP-seq technology using standard library preparation methods, thus providing global epigenomic maps in highly relevant embryonic tissues.

Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples

Here, we describe a chromatin immunoprecipitation (ChIP) and ChIP-seq library preparation protocol to generate global epigenomic profiles from low-abundance chicken embryonic samples.

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, ...

Transient Expression of Foreign Genes in Insect Cells (sf9) for Protein Functional Assay

The transient gene expression system is one of the most important technologies for performing protein functional analysis in the baculovirus in vitro cell culture system. This system was developed to express foreign genes under the control of the baculoviral promoter in transient expression plasmids. Furthermore, this system can be applied to a functional assay of either the baculovirus itself or foreign proteins. The most widely and commercially available transient gene expression system is developed based on the immediate-early gene (IE) promoter of Orgyia pseudotsugata multicapsid nucleopolyhedrovirus (OpMNPV). However, a low expression level of foreign genes in insect cells was observed. Therefore, a transient gene expression system was constructed for improving protein expression. In this system, recombinant plasmids were constructed to contain the target sequence under the control of the Drosophila heat shock 70 (Dhsp70) promoter. This protocol presents the application of this heat shock-based pDHsp/V5-His (V5 epitope with 6 histidine)/Spodoptera frugiperda cell (sf9 cell) system; this system is available not only for gene expression but also for evaluating the anti-apoptotic activity of candidate proteins in insect cells. Furthermore, this system can be either transfected with one recombinant plasmid or co-transfected two potentially functionally antagonistic recombinant plasmids in insect cells. The protocol demonstrates the efficiency of this system and provides a practical case of this technique.

Transient Expression of Foreign Genes in Insect Cells sf9 for Protein Functional Assay

This protocol describes a heat shock-induced protein expression system (pDHsp/V5-His/sf9 cell system), which can be used for either expressing foreign proteins or evaluating the anti-apoptotic activity of potential foreign proteins and their truncated amino acids in insect cells.

The transient gene expression system is one of the most important technologies for performing protein functional analysis in the baculovirus in vitro cell ...

Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens

&#8211;Archived, clinically classified formalin-fixed paraffin-embedded (FFPE) tissues can provide nucleic acids for retrospective molecular studies of cancer development. By using non-invasive or pre-malignant lesions from patients who later develop invasive disease, gene expression analyses may help identify early molecular alterations that predispose to cancer risk. It has been well described that nucleic acids recovered from FFPE tissues have undergone severe physical damage and chemical modifications, which make their analysis difficult and generally requires adapted assays. MicroRNAs (miRNAs), however, which represent a small class of RNA molecules spanning only up to ~18&#8211;24 nucleotides, have been shown to withstand long-term storage and have been successfully analyzed in FFPE samples. Here we present a 3&#39; barcoded complementary DNA (cDNA) library preparation protocol specifically optimized for the analysis of small RNAs extracted from archived tissues, which was recently demonstrated to be robust and highly reproducible when using archived clinical specimens stored for up to 35 years. This library preparation is well adapted to the multiplex analysis of compromised/degraded material where RNA samples (up to 18) are ligated with individual 3&#39; barcoded adapters and then pooled together for subsequent enzymatic and biochemical preparations prior to analysis. All purifications are performed by polyacrylamide gel electrophoresis (PAGE), which allows size-specific selections and enrichments of barcoded small RNA species. This cDNA library preparation is well adapted to minute RNA inputs, as a pilot polymerase chain reaction (PCR) allows determination of a specific amplification cycle to produce optimal amounts of material for next-generation sequencing (NGS). This approach was optimized for the use of degraded FFPE RNA from specimens archived for up to 35 years and provides highly reproducible NGS data.

Formalin-fixed paraffin-embedded specimens represent a valuable source of molecular biomarkers of human diseases. Here we present a laboratory-based cDNA library preparation protocol, initially designed with fresh frozen RNA, and optimized for the analysis of archived microRNAs from tissues stored up to 35 years.

&#8211;Archived, clinically classified formalin-fixed paraffin-embedded (FFPE) tissues can provide nucleic acids for retrospective molecular studies of ...

Isolation, Characterization and MicroRNA-based Genetic Modification of Human Dental Follicle Stem Cells

To date, several stem cell types at different developmental stages are in the focus for the treatment of degenerative diseases. Yet, certain aspects, such as initial massive cell death and low therapeutic effects, impaired their broad clinical translation. Genetic engineering of stem cells prior to transplantation emerged as a promising method to optimize therapeutic stem cell effects. However, safe and efficient gene delivery systems are still lacking. Therefore, the development of suitable methods may provide an approach to resolve current challenges in stem cell-based therapies.
The present protocol describes the extraction and characterization of human dental follicle stem cells (hDFSCs) as well as their non-viral genetic modification. The postnatal dental follicle unveiled as a promising and easily accessible source for harvesting adult multipotent stem cells possessing high proliferation potential. The described isolation procedure presents a simple and reliable method to harvest hDFSCs from impacted wisdom teeth. Also this protocol comprises methods to define stem cell characteristics of isolated cells. For genetic engineering of hDFSCs, an optimized cationic lipid-based transfection strategy is presented enabling highly efficient microRNA introduction without causing cytotoxic effects. MicroRNAs are suitable candidates for transient cell manipulation, as these small translational regulators control the fate and behavior of stem cells without the hazard of stable genome integration. Thus, this protocol represents a safe and efficient procedure for engineering of hDFSCs that may become important for optimizing their therapeutic efficacy.

This protocol describes the transient genetic engineering of dental stem cells extracted from the human dental follicle. The applied non-viral modification strategy may become a basis for the improvement of therapeutic stem cell products.

To date, several stem cell types at different developmental stages are in the focus for the treatment of degenerative diseases. Yet, certain aspects, such ...

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila

Advances in sequencing technology have made whole-genome and whole-exome datasets more accessible for both clinical diagnosis and cutting-edge human genetics research. Although a number of in silico algorithms have been developed to predict the pathogenicity of variants identified in these datasets, functional studies are critical to determining how specific genomic variants affect protein function, especially for missense variants. In the Undiagnosed Diseases Network (UDN) and other rare disease research consortia, model organisms (MO) including Drosophila, C. elegans, zebrafish, and mice are actively used to assess the function of putative human disease-causing variants. This protocol describes a method for the functional assessment of rare human variants used in the Model Organisms Screening Center Drosophila Core of the UDN. The workflow begins with gathering human and MO information from multiple public databases, using the MARRVEL web resource to assess whether the variant is likely to contribute to a patient&#39;s condition as well as design effective experiments based on available knowledge and resources. Next, genetic tools (e.g., T2A-GAL4 and UAS-human cDNA lines) are generated to assess the functions of variants of interest in Drosophila. Upon development of these reagents, two-pronged functional assays based on rescue and overexpression experiments can be performed to assess variant function. In the rescue branch, the endogenous fly genes are &#34;humanized&#34;&#160;by replacing the orthologous Drosophila gene with reference or variant human transgenes. In the overexpression branch, the reference and variant human proteins are exogenously driven in a variety of tissues. In both cases, any scorable phenotype (e.g., lethality, eye morphology, electrophysiology) can be used as a read-out, irrespective of the disease of interest. Differences observed between reference and variant alleles suggest a variant-specific effect, and thus likely pathogenicity. This protocol allows rapid, in vivo assessments of putative human disease-causing variants of genes with known and unknown functions.

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila

The goal of this protocol is to outline the design and performance of in vivo experiments in Drosophila melanogaster to assess the functional consequences of rare gene variants associated with human diseases.

Advances in sequencing technology have made whole-genome and whole-exome datasets more accessible for both clinical diagnosis and cutting-edge human ...

The Use of Mouse Mammary Tumor Cells in an In Vitro Invasion Assay as a Measure of Oncogenic Cell Behavior

The in vitro invasion assay uses a protein-rich matrix in a Boyden chamber to measure the ability of cultured cells to pass through the matrix and a porous membrane in a process analogous to the initial steps of cancer cell metastasis. The tested cells can be altered for the gene expression or treated with inhibitors to test for changes in the invasion potential. This experiment tests the aggressive phenotype of the mouse mammary tumor cells to discover and characterize the potential oncogenes that promote cell invasion. This technique, however, can be versatile and adapted to many different applications. The experiment itself can be done in one day and the results are acquired by light microscopy in less than a day. The results include counts of the number of invading cells for comparison and analysis. The in vitro invasion assay is a rapid, inexpensive, and clear-cut method for determining cell behavior in a culture that can be used as an initial assessment before more involved in vivo assays.

The in vitro cell invasion assay is used to measure the potential of cancer metastasis by quantifying the cellular potential for invasion and migration using cell culture inserts containing protein matrix. Cells are challenged to migrate through the protein matrix and a porous membrane, towards a chemoattractant, and then quantified by light microscopy.

The in vitro invasion assay uses a protein-rich matrix in a Boyden chamber to measure the ability of cultured cells to pass through the matrix and a ...