The authors thank Sophie Patrier and Marianne Par&#233;sy for sharing the original flow cytometry protocol, and Promega and Qiagen for providing supplies and reagents. This work was supported by the R&#233;seau Qu&#233;b&#233;cois en Reproduction and the Canadian Institute for Health Research (MOP-130364) to R.S.

<ol>
	<li>Szulman, A. E., Surti, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+syndromes+of+hydatidiform+mole.+II.+Morphologic+evolution+of+the+complete+and+partial+mole.">The syndromes of hydatidiform mole. II. Morphologic evolution of the complete and partial mole.</a> American Journal of Obstetrics &amp; Gynecology. 132 (1), 20-27 (1978).</li><li>Fukunaga, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interobserver+and+intraobserver+variability+in+the+diagnosis+of+hydatidiform+mole.">Interobserver and intraobserver variability in the diagnosis of hydatidiform mole.</a> The American Journal of Surgical Pathology. 29 (7), 942-947 (2005).</li><li>Gupta, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnostic+reproducibility+of+hydatidiform+moles:+ancillary+techniques+(p57+immunohistochemistry+and+molecular+genotyping)+improve+morphologic+diagnosis+for+both+recently+trained+and+experienced+gynecologic+pathologists.">Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis for both recently trained and experienced gynecologic pathologists.</a> The American Journal of Surgical Pathology. 36 (12), 1747-1760 (2012).</li><li>Howat, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+histopathologists+reliably+diagnose+molar+pregnancy?.">Can histopathologists reliably diagnose molar pregnancy?.</a> Journal of Clinical Pathology. 46 (7), 599-602 (1993).</li><li>Banet, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+hydatidiform+moles:+analysis+of+a+prospective+series+with+p57+immunohistochemistry+and+molecular+genotyping.">Characteristics of hydatidiform moles: analysis of a prospective series with p57 immunohistochemistry and molecular genotyping.</a> Modern Pathology. 27 (2), 238-254 (2014).</li><li>Lipata, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precise+DNA+genotyping+diagnosis+of+hydatidiform+mole.">Precise DNA genotyping diagnosis of hydatidiform mole.</a> Obstetrics &amp; Gynecology. 115 (4), 784-794 (2010).</li><li>Buza, N., Hui, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+hydatidiform+mole:+histologic+parameters+in+correlation+with+DNA+genotyping.">Partial hydatidiform mole: histologic parameters in correlation with DNA genotyping.</a> International Journal of Gynecologic Pathology. 32 (3), 307-315 (2013).</li><li>Fisher, R. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frequency+of+heterozygous+complete+hydatidiform+moles,+estimated+by+locus-specific+minisatellite+and+Y+chromosome-specific+probes.">Frequency of heterozygous complete hydatidiform moles, estimated by locus-specific minisatellite and Y chromosome-specific probes.</a> Human Genetics. 82 (3), 259-263 (1989).</li><li>Murdoch, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+in+NALP7+cause+recurrent+hydatidiform+moles+and+reproductive+wastage+in+humans.">Mutations in NALP7 cause recurrent hydatidiform moles and reproductive wastage in humans.</a> Nature Genetics. 38 (3), 300-302 (2006).</li><li>Parry, D. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+causing+familial+biparental+hydatidiform+mole+implicate+c6orf221+as+a+possible+regulator+of+genomic+imprinting+in+the+human+oocyte.">Mutations causing familial biparental hydatidiform mole implicate c6orf221 as a possible regulator of genomic imprinting in the human oocyte.</a> American Journal of Human Genetics. 89 (3), 451-458 (2011).</li><li>Nguyen, N. M., Slim, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+and+Epigenetics+of+Recurrent+Hydatidiform+Moles:+Basic+Science+and+Genetic+Counselling.">Genetics and Epigenetics of Recurrent Hydatidiform Moles: Basic Science and Genetic Counselling.</a> Current Obstetrics and Gynecology Reports. 3, 55-64 (2014).</li><li>Sebire, N. J., Savage, P. M., Seckl, M. J., Fisher, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histopathological+features+of+biparental+complete+hydatidiform+moles+in+women+with+NLRP7+mutations.">Histopathological features of biparental complete hydatidiform moles in women with NLRP7 mutations.</a> Placenta. 34 (1), 50-56 (2013).</li><li>Nguyen, N. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+genotype-phenotype+correlations+between+NLRP7+mutations+and+the+balance+between+embryonic+tissue+differentiation+and+trophoblastic+proliferation.">Comprehensive genotype-phenotype correlations between NLRP7 mutations and the balance between embryonic tissue differentiation and trophoblastic proliferation.</a> Journal of Medical Genetics. 51 (9), 623-634 (2014).</li><li>Brown, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recurrent+pregnancy+loss+in+a+woman+with+NLRP7+mutation:+not+all+molar+pregnancies+can+be+easily+classified+as+either+"partial"+or+"complete"+hydatidiform+moles.">Recurrent pregnancy loss in a woman with NLRP7 mutation: not all molar pregnancies can be easily classified as either "partial" or "complete" hydatidiform moles.</a> International Journal of Gynecologic Pathology. 32 (4), 399-405 (2013).</li><li>Colgan, T. J., Chang, M. C., Nanji, S., Kolomietz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Reappraisal+of+the+Incidence+of+Placental+Hydatidiform+Mole+Using+Selective+Molecular+Genotyping.">A Reappraisal of the Incidence of Placental Hydatidiform Mole Using Selective Molecular Genotyping.</a> The International Journal of Gynecological Cancer. 26 (7), 1345-1350 (2016).</li><li>Murphy, K. M., McConnell, T. G., Hafez, M. J., Vang, R., Ronnett, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+genotyping+of+hydatidiform+moles:+analytic+validation+of+a+multiplex+short+tandem+repeat+assay.">Molecular genotyping of hydatidiform moles: analytic validation of a multiplex short tandem repeat assay.</a> The Journal of Molecular Diagnostics. 11 (6), 598-605 (2009).</li></ol>

The authors have nothing to disclose.

HM are abnormal human pregnancies with heterogeneous etiologies and have different histological and genotypic types, which makes their accurate classification and diagnosis challenging. Histopathological morphological evaluation was often proven inaccurate and is therefore unreliable on its own to classify HM into CHM and PHM and distinguish them from non-molar miscarriages. Therefore, an accurate diagnosis of HM requires the use of other methods such as multiplex microsatellite DNA genotyping, ploidy analysis by flow cy...

A hydatidiform mole (HM) is an abnormal human pregnancy characterized by abnormal embryonic development, hyperproliferation of the trophoblast, and hydropic degeneration of chorionic villi (CV). Historically, HM used to be divided into two types, complete HM (CHM) and partial HM (PHM) based only on morphological evaluation1. However, it has been shown that morphological evaluation alone is not sufficient to classify HM into the two subtypes (CHM and PHM) and distinguish them from non-molar miscarriages2,3,4.
Because CHM and PHM have different propensities to malignancies, it is therefore important to accurately determine the genotypic type of HM to provide appropriate follow-up and management to the patients. Consequently, in the past decades, several methodologies have been developed and evolved for the purpose of identifying the parental contribution to the molar tissues and reaching a correct classification of HM. These include karyotype analysis, chromosomal banding polymorphism, human leukocyte antigen (HLA) serological typing, restriction fragment length polymorphism, variable number of tandem repeats, microsatellite genotyping, flow cytometry, and p57KIP2 immunohistochemistry. This has allowed accurate subdivision of HM conceptions based on the parental contribution to their genomes, as follows: CHM, which are diploid androgenetic monospermic or diploid androgenetic dispermic, and PHM, which are triploid, dispermic in 99% and monospermic in 1% of the cases5,6,7,8. Furthermore, there is another genotypic type of HM that emerged in the past two decades, which is diploid biparental. The latter is mostly recurrent and may affect a single family member (simplex cases) or at least two family members (familial cases). These diploid biparental moles are mostly caused by recessive mutations in NLRP7 or KHDC3L in the patients9,10,11,12. Diploid biparental HM in patients with recessive mutations in NLRP7 may be diagnosed as CHM or PHM by morphological analysis and this appears to be associated with the severity of the mutations in the patients13,14. In addition to the classification of HM according to their genotypes, the introduction and use of several genotyping methods allowed the distinction of the various molar entities from non-molar miscarriages, such as aneuploid diploid biparental conceptions and other types of conceptions5,15. Such conceptions may have some trophoblast proliferation and abnormal villous morphology that mimic, to some extent, some morphological features of HM.
The purpose of this article is to provide detailed protocols for multiplex genotyping and flow cytometry of formalin-fixed paraffin-embedded (FFPE) tissues, and comprehensive analyses of the results of these methods and their integration with other methods for correct and conclusive diagnosis of molar tissues.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>BD FACS Canto II</td>
			<td>BD BioSciences</td>
			<td>338960</td>
			<td></td>
		</tr>
		<tr>
			<td>Capillary electrophoresis instrument: Genomes Applied Biosystems 3730xl DNA Analyzer</td>
			<td>Applied biosystems</td>
			<td>313001R</td>
			<td>Service offered by the Centre for Applied Genomics (http://www.tcag.ca)</td>
		</tr>
		<tr>
			<td>Citric acid</td>
			<td>Sigma</td>
			<td>251275</td>
			<td></td>
		</tr>
		<tr>
			<td>Cytoseal 60, histopathology mounting medium</td>
			<td>Fisher</td>
			<td>23244257</td>
			<td></td>
		</tr>
		<tr>
			<td>Eosin Y stock solution (1%)</td>
			<td>Fisher</td>
			<td>SE23-500D</td>
			<td></td>
		</tr>
		<tr>
			<td>FCSalyzer - flow cytometry analysis software</td>
			<td>SourceForge</td>
			<td>-</td>
			<td>https://sourceforge.net/projects/fcsalyzer/</td>
		</tr>
		<tr>
			<td>FFPE Qiagen kit</td>
			<td>Qiagen</td>
			<td>80234</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Fine Science Tools</td>
			<td>11295-51</td>
			<td>For sectioning and for the cleaning process</td>
		</tr>
		<tr>
			<td>Glacial Acetic Acid (Concentrated)</td>
			<td>Sigma</td>
			<td>A6283-500mL</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass coverslips: Cover Glass</td>
			<td>Fisher</td>
			<td>12-541a</td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin</td>
			<td>Fisher</td>
			<td>CS401-1D</td>
			<td></td>
		</tr>
		<tr>
			<td>Highly deionized formamide: Hi-Di Formamide</td>
			<td>Thermofisher</td>
			<td>4311320</td>
			<td></td>
		</tr>
		<tr>
			<td>IHC platform: Benchmark Ultra</td>
			<td>Roche</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Kimwipes</td>
			<td>Ultident</td>
			<td>30-34120</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtome</td>
			<td>Leica</td>
			<td>RM2135</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtome blades</td>
			<td>Fisher</td>
			<td>12-634-1C</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitex filtering mesh, 48 microns</td>
			<td>Filmar</td>
			<td>74011</td>
			<td>http://www.filmar.qc.ca/index.php?filet=produits&#38;id=51&#38;lang=en ; any other filter is suitable, but this is an inexpensive and effective option from a non-research company</td>
		</tr>
		<tr>
			<td>p57 antibody</td>
			<td>Cell Marque</td>
			<td>457M</td>
			<td></td>
		</tr>
		<tr>
			<td>Pasteur pipette</td>
			<td>VWR</td>
			<td>53499-632</td>
			<td></td>
		</tr>
		<tr>
			<td>PCR machine</td>
			<td>Perkin Elmer, Applied Biosystems</td>
			<td>GeneAmp PCR System 9700</td>
			<td></td>
		</tr>
		<tr>
			<td>PeakScanner 1.0</td>
			<td>Applied Biosystems</td>
			<td>4381867</td>
			<td>Software for genotyping analysis.</td>
		</tr>
		<tr>
			<td>Pepsin from porcine gastric mucosa</td>
			<td>Sigma</td>
			<td>P7012</td>
			<td></td>
		</tr>
		<tr>
			<td>Polystyrene round-bottom tubes</td>
			<td>BD Falcon</td>
			<td>352058</td>
			<td></td>
		</tr>
		<tr>
			<td>Positively charged slides: Superfrost Plus 25x75mm</td>
			<td>Fisher</td>
			<td>1255015</td>
			<td></td>
		</tr>
		<tr>
			<td>PowerPlex 16 HS System</td>
			<td>Promega Corporation</td>
			<td>DC2102</td>
			<td></td>
		</tr>
		<tr>
			<td>Propidium Iodide</td>
			<td>Sigma</td>
			<td>P4864</td>
			<td></td>
		</tr>
		<tr>
			<td>Ribonuclease A from bovine pancreas</td>
			<td>Sigma</td>
			<td>R4875</td>
			<td></td>
		</tr>
		<tr>
			<td>Separation matrix: POP-7 Polymer</td>
			<td>Thermofisher</td>
			<td>4352759</td>
			<td></td>
		</tr>
		<tr>
			<td>UltraPure Agarose</td>
			<td>Fisher</td>
			<td>16500-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Fisher</td>
			<td>X3P1GAL</td>
			<td></td>
		</tr>
	</tbody>
</table>

microsatellite dna genotyping and flow cytometry ploidy analyses of formalin-fixed paraffin-embedded hydatidiform molar tissues

Hydatidiform mole (HM) is an abnormal human pregnancy characterized by excessive trophoblastic proliferation and abnormal embryonic development. There are two types of HM based on microscopic morphological evaluation, complete HM (CHM) and partial HM (PHM). These can be further subdivided based on the parental contribution to the molar genomes. Such characterization of HM, by morphology and genotype analyses, is crucial for patient management and for the fundamental understanding of this intriguing pathology. It is well documented that morphological analysis of HM is subject to wide interobserver variability and is not sufficient on its own to accurately classify HM into CHM and PHM and distinguish them from hydropic non-molar abortions. Genotyping analysis is mostly performed on DNA and tissues from formalin-fixed paraffin-embedded (FFPE) products of conception, which have less than optimal quality and may consequently lead to wrong conclusions. In this article, detailed protocols for multiplex genotyping and flow cytometry analyses of FFPE molar tissues are provided, along with the interpretation of the results of these methods, their troubleshooting, and integration with the morphological evaluation, p57KIP2 immunohistochemistry, and fluorescence in situ hybridization (FISH) to reach a correct and robust diagnosis. Here, the authors share the methods and lessons learned in the past 10 years from the analysis of approximately 400 products of conception.

The complexity of molar tissues and the fact that they may have various genotypes necessitates stringent analysis and the use of several methods such as morphological evaluation, p57 immunohistochemistry, microsatellite genotyping, flow cytometry, and FISH. For example, one patient (1790) was referred with two PHM that were found to be triploid by microarray analysis of the POCs only. The patient was therefore diagnosed with recurrent PHM. Microsatellite genotyping of her two &#34;PHM&#34...

Watch this Scientific Journal Video about Microsatellite DNA Genotyping and Flow Cytometry Ploidy Analyses of Formalin-fixed Paraffin-embedded Hydatidiform Molar Tissues at JoVE.com

Microsatellite DNA Genotyping and Flow Cytometry Ploidy Analyses of Formalin-fixed Paraffin-embedded Hydatidiform Molar Tissues

Hydatidiform moles are abnormal human pregnancies with heterogeneous aetiologies that can be classified according to their morphological features and parental contribution to the molar genomes. Here, protocols of multiplex microsatellite DNA genotyping and flow cytometry of formalin-fixed paraffin-embedded molar tissues are described in detail, together with results&#8217; interpretation and integration.

Hydatidiform mole (HM) is an abnormal human pregnancy characterized by excessive trophoblastic proliferation and abnormal embryonic development. There are ...

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Genetics

9.0K Views.  McGill University. Hydatidiform moles are abnormal human pregnancies with heterogeneous aetiologies that can be classified according to their morphological features and parental contribution to the molar genomes. Here, protocols of multiplex microsatellite DNA genotyping and flow cytometry of formalin-fixed paraffin-embedded molar tissues are described in detail, together with results’ interpretation and integration.

Video: Microsatellite DNA Genotyping and Flow Cytometry Ploidy Analyses of Formalin-fixed Paraffin-embedded Hydatidiform Molar Tissues

siRNA Transfection and EMSA Analyses on Freshly Isolated Human Villous Cytotrophoblasts

Human primary villous cytotrophoblasts are a very useful source of primary cells to study placental functions and regulatory mechanisms, and to comprehend diseases related to pregnancy. In this protocol, human primary villous cytotrophoblasts freshly isolated from placentas through a standard DNase/trypsin protocol are microporated with small interfering RNA (siRNA). This approach provided greater efficiency for siRNA transfection when compared to a lipofection-based method. Transfected cells can subsequently be analyzed by standard Western blot within a time frame of 3-4 days post-transfection. In addition, using cultured primary villous cytotrophoblasts, Electrophoretic Mobility Shift Assay (EMSA) analysis was optimized and performed on extracts from days 1 to 4. The use of these cultured primary cells and the protocol described allow for an evaluation of the implication of specific genes and transcription factors in the process of villous cytotrophoblast differentiation into a syncytiotrophoblast-like cell layer. However, the limited time span allowable in culture precludes the use of methods requiring more time, such as generation of a stable cell population. Therefore testing of this cell population requires highly optimized gene transfer protocols.

This protocol describes a method for efficiently transfecting siRNA in freshly isolated human villous cytotrophoblasts using microporation and identifying DNA-protein complexes in these cells. Transfected cells can be monitored by Western blot and EMSA analyses during the 4-day culture time.

Human primary villous cytotrophoblasts are a very useful source of primary cells to study placental functions and regulatory mechanisms, and to comprehend ...

Methyl-binding DNA capture Sequencing for Patient Tissues

Methylation is one of the essential epigenetic modifications to the DNA, which is responsible for the precise regulation of genes required for stable development and differentiation of different tissue types. Dysregulation of this process is often the hallmark of various diseases like cancer. Here, we outline one of the recent sequencing techniques, Methyl-Binding DNA Capture sequencing (MBDCap-seq), used to quantify methylation in various normal and disease tissues for large patient cohorts. We describe a detailed protocol of this affinity enrichment approach along with a bioinformatics pipeline to achieve optimal quantification. This technique has been used to sequence hundreds of patients across various cancer types as a part of the 1,000 methylome project (Cancer Methylome System).

Here we present a protocol to investigate genome wide DNA methylation in large scale clinical patient screening studies using the Methyl-Binding DNA Capture sequencing (MBDCap-seq or MBD-seq) technology and the subsequent bioinformatics analysis pipeline.

Methylation is one of the essential epigenetic modifications to the DNA, which is responsible for the precise regulation of genes required for stable ...

Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry

An improved version of a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for genotyping toxic pufferfish species by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) is described. DNA extraction is carried out using a silica membrane-based DNA extraction kit. After the PCR amplification using a detergent-free PCR buffer, restriction enzymes are added to the solution without purifying the reaction solution. A reverse-phase silica monolith column and a Fourier transform high resolution mass spectrometer having a modified Kingdon trap analyzer are employed for separation and detection, respectively. The mobile phase, consisting of 400 mM 1,1,1,3,3,3-hexafluoro-2-propanol, 15 mM triethylamine (pH 7.9) and methanol, is delivered at a flow rate of 0.4 ml/min. The cycle time for LC/ESI-MS analysis is 8 min including equilibration of the column. Deconvolution software having an isotope distribution model of the oligonucleotide is used to calculate the corresponding monoisotopic mass from the mass spectrum. For analysis of oligonucleotides (range 26-79 nucleotides), mass accuracy was 0.62 &#177; 0.74 ppm (n = 280) and excellent accuracy and precision were sustained for 180 hr without use of a lock mass standard.

An improved polymerase chain reaction-restriction fragment length polymorphism method for genotyping pufferfish species by liquid chromatography/mass spectrometry is described. A reverse-phase silica monolith column is employed for separating digested amplicons. This method can elucidate the monoisotopic masses of oligonucleotides, which is useful for identifying base composition.

An improved version of a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for genotyping toxic pufferfish species by ...

Assessment of DNA Contamination in RNA Samples Based on Ribosomal DNA

One method extensively used for the quantification of gene expression changes and transcript abundances is reverse-transcription quantitative real-time PCR (RT-qPCR). It provides accurate, sensitive, reliable, and reproducible results. Several factors can affect the sensitivity and specificity of RT-qPCR. Residual genomic DNA (gDNA) contaminating RNA samples is one of them. In gene expression analysis, non-specific amplification due to gDNA contamination will overestimate the abundance of transcript levels and can affect the RT-qPCR results. Generally, gDNA is detected by qRT-PCR using primer pairs annealing to intergenic regions or an intron of the gene of interest. Unfortunately, intron/exon annotations are not yet known for all genes from vertebrate, bacteria, protist, fungi, plant, and invertebrate metazoan species.
Here we present a protocol for detection of gDNA contamination in RNA samples by using ribosomal DNA (rDNA)-based primers. The method is based on the unique features of rDNA: their multigene nature, highly conserved sequences, and high frequency in the genome. Also as a case study, a unique set of primers were designed based on the conserved region of ribosomal DNA (rDNA) in the Poaceae family. The universality of these primer pairs was tested by melt curve analysis and agarose gel electrophoresis. Although our method explains how rDNA-based primers can be applied for the gDNA contamination assay in the Poaceae family,&#160;it could be easily used to other prokaryote and eukaryote species

Here, we present a protocol for tracing genomic DNA (gDNA) contamination in RNA samples. The presented method utilizes primers specific for the internal transcribed spacer region (ITS) of ribosomal DNA (rDNA) genes. The method is suited for reliable and sensitive detection of DNA contamination in most eukaryotes and prokaryotes.

One method extensively used for the quantification of gene expression changes and transcript abundances is reverse-transcription quantitative real-time ...

Manipulation of Ploidy in Caenorhabditis elegans

Mechanisms that involve whole genome polyploidy play important roles in development and evolution; also, an abnormal generation of tetraploid cells has been associated with both the progression of cancer and the development of drug resistance. Until now, it has not been feasible to easily manipulate the ploidy of a multicellular animal without generating mostly sterile progeny. Presented here is a simple and rapid protocol for generating tetraploid Caenorhabditis elegans animals from any diploid strain. This method allows the user to create a bias in chromosome segregation during meiosis, ultimately increasing ploidy in C. elegans. This strategy relies on the transient reduction of expression of the rec-8 gene to generate diploid gametes. A rec-8 mutant produces diploid gametes that can potentially produce tetraploids upon fertilization. This tractable scheme has been used to generate tetraploid strains carrying mutations and chromosome rearrangements to gain insight into chromosomal dynamics and interactions during pairing and synapsis in meiosis. This method is efficient for generating stable tetraploid strains without genetic markers, can be applied to any diploid strain, and can be used to derive triploid C. elegans. This straightforward method is useful for investigating other fundamental biological questions relevant to genome instability, gene dosage, biological scaling, extracellular signaling, adaptation to stress, development of resistance to drugs, and mechanisms of speciation.

Manipulation of Ploidy in Caenorhabditis elegans

This method allows for the generation of tetraploid and triploid Caenorhabditis nematodes from any diploid strain. Polyploid strains generated by this method have been used to study chromosome interactions in meiotic prophase, and this method is useful for examining important basic questions in cell, developmental, evolutionary, and cancer biology.

Mechanisms that involve whole genome polyploidy play important roles in development and evolution; also, an abnormal generation of tetraploid cells has ...

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 ...

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry

Complex diseases are often underpinned by multiple common genetic variants that contribute to disease susceptibility. Here, we describe a cost-effective tag single nucleotide polymorphism (SNP) approach using a multiplexed genotyping assay with mass spectrometry, to investigate gene pathway associations in clinical cohorts. We investigate the food allergy candidate locus Interleukin13 (IL13) as an example. This method efficiently maximizes the coverage by taking advantage of shared linkage disequilibrium (LD) within a region. Selected LD SNPs are then designed into a multiplexed assay, enabling up to 40 different SNPs to be analyzed simultaneously, boosting cost-effectiveness. Polymerase chain reaction (PCR) is used to amplify the target loci, followed by single nucleotide extension, and the amplicons are then measured using matrix-assisted laser desorption/ionization-time of flight(MALDI-TOF) mass spectrometry. The raw output is analyzed with the genotype calling software, using stringent quality control definitions and cut-offs, and high probability genotypes are determined and output for data analysis.

Identification of genetic variants contributing to complex human disease allows us to identify novel mechanisms. Here, we demonstrate a multiplex genotyping approach to candidate genes or gene pathway analysis that maximizes the coverage at low cost and is amenable to cohort-based studies.

Complex diseases are often underpinned by multiple common genetic variants that contribute to disease susceptibility. Here, we describe a cost-effective ...

High-throughput DNA Extraction and Genotyping of 3dpf Zebrafish Larvae by Fin Clipping

Zebrafish (Danio rerio) possess orthologues for 84% of the genes known to be associated with human diseases. In addition, these animals have a short generation time, are easy to handle, display a high reproductive rate, low cost, and are easily amenable to genetic manipulations by microinjection of DNA in embryos. Recent advances in gene editing tools are enabling precise introduction of mutations and transgenes in zebrafish. Disease modeling in zebrafish often leads to larval phenotypes and early death which can be challenging to interpret if genotypes are unknown. This early identification of genotypes is also needed in experiments requiring sample pooling, such as in gene expression or mass spectrometry studies. However, extensive genotypic screening is limited by traditional methods, which in most labs are performed only on adult zebrafish or in postmortem larvae. We addressed this problem by adapting a method for the isolation of PCR-ready genomic DNA from live zebrafish larvae that can be achieved as early as 72 h post-fertilization (hpf). This time and cost-effective technique, improved from a previously published genotyping protocol, allows the identification of genotypes from microscopic fin biopsies. The fins quickly regenerate as the larvae develop. Researchers are then able to select and raise the desired genotypes to adulthood by utilizing this high-throughput PCR-based genotyping procedure.

Zebrafish have been used as reliable genetic model organisms in biomedical research, especially with the advent of gene-editing technologies. When larval phenotypes are expected, DNA extraction and genotype identification can be challenging. Here, we describe an efficient genotyping procedure for zebrafish larvae, by tail clipping, as early as 72-h post-fertilization.

Zebrafish (Danio rerio) possess orthologues for 84% of the genes known to be associated with human diseases. In addition, these animals have a short ...

Measurement of BK-polyomavirus Non-Coding Control Region Driven Transcriptional Activity Via Flow Cytometry

Polyomaviruses, like the BK-polyomavirus (BKPyV), can cause severe pathologies in immunocompromised patients. However, since highly effective antivirals are currently not available, methods measuring the impact of potential antiviral agents are required. Here, a dual fluorescence reporter that allows the analysis of the BKPyV non-coding control-region (NCCR) driven early and late promoter activity was constructed to quantify the impact of potential antiviral drugs on viral gene expression via tdTomato and eGFP expression. In addition, by cloning BKPyV-NCCR amplicons which in this protocol have been exemplarily obtained from the blood-derived DNA of immunocompromised renal transplanted patients, the impact of NCCR-rearrangements on viral gene expression can be determined. Following cloning of the patient derived amplicons, HEK293T cells were transfected with the reporter-plasmids, and treated with potential antiviral agents. Subsequently, cells were subjected to FACS-analysis for measuring mean fluorescence intensities 72 h post transfection. To also test the analysis of drugs that have a potential cell cycle inhibiting effect, only transfected and thus fluorescent cells are used. Since this assay is performed in large T Antigen expressing cells, the impact of early and late expression can be analyzed in a mutually independent manner.

In this manuscript, a protocol is presented to perform FACS-based measurement of BK-polyomavirus transcriptional activity by using HEK293T cells transfected with a bidirectional reporter plasmid expressing tdTomato and eGFP. This method further allows to quantitatively determine the influence of novel compounds on viral transcription.

Polyomaviruses, like the BK-polyomavirus (BKPyV), can cause severe pathologies in immunocompromised patients. However, since highly effective antivirals ...

Single-Molecule F&ouml;rster Resonance Energy Transfer Methods for Real-Time Investigation of the Holliday Junction Resolution by GEN1

Bulk methods measure the ensemble behavior of molecules, in which individual reaction rates of the underlying steps are averaged throughout the population. Single-molecule F&#246;rster resonance energy transfer (smFRET) provides a recording of the conformational changes taking place by individual molecules in real-time. Therefore, smFRET is powerful in measuring structural changes in the enzyme or substrate during binding and catalysis. This work presents a protocol for single-molecule imaging of the interaction of a four-way Holliday junction (HJ) and gap endonuclease I (GEN1), a cytosolic homologous recombination enzyme. Also presented are single-color and two-color alternating excitation (ALEX) smFRET experimental protocols to follow the resolution of the HJ by GEN1 in real-time. The kinetics of GEN1 dimerization are determined at the HJ, which has been suggested to play a key role in the resolution of the HJ and has remained elusive until now. The techniques described here can be widely applied to obtain valuable mechanistic insights of many enzyme-DNA systems.

Single-Molecule F&#246;rster Resonance Energy Transfer Methods for Real-Time Investigation of the Holliday Junction Resolution by GEN1

Presented here is a protocol for performing single-molecule F&#246;rster resonance energy transfer to study HJ resolution. Two-color alternating excitation is used for determining the dissociation constants. Single-color time lapse smFRET is then applied in real-time cleavage assays to obtain the dwell time distribution prior to HJ resolution.