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Multiplexed genome editing by CRISPR-Un1Cas12f1 restores dystrophin expression in a mouse model of Duchenne muscular dystrophy.

The compact type V clustered regularly interspaced short palindromic repeats (CRISPR) nuclease Un1Cas12f1 is compatible with adeno-associated virus (AAV)-mediated genome editing, although the protospacer adjacent motif (PAM) requirements and capacity for multiplexed genome editing remain undefined. Here, we show that Un1Cas12f1 exhibits a broad tolerance for non-canonical PAMs, including Y-rich motifs with a preference for TTCR and TCTA PAMs, thereby expanding the genomic targeting range. We further demonstrate that a tandem sgRNA array expressed from a single transcript supports Un1Cas12f1-mediated multiplexed genome editing at up to five distinct genomic loci. Leveraging this multiplexing capability, we achieved targeted excision of the Dmd exon 23 through intramuscular delivery of an all-in-one AAV vector encoding Un1Cas12f1 and a CRISPR array. This treatment restored the disrupted open reading frame and dystrophin expression in a mouse model of Duchenne muscular dystrophy (DMD). Together, these findings establish Un1Cas12f1 as a compact CRISPR system capable of multiplexed genome editing and demonstrate its therapeutic potential for DMD.

Journal Article↗

Homogeneous multiplex genotyping of hemochromatosis mutations with fluorescent hybridization probes.

Multiplex polymerase chain reaction amplification and genotyping by fluorescent probe melting temperature (Tm) was used to simultaneously detect multiple variants in the hereditary hemochromatosis gene. Homogenous real-time analysis by fluorescent melting curves has previously been used to genotype single base mismatches; however, the current method introduces a new probe design for fluorescence resonance energy transfer and demonstrates allele multiplexing by Tm for the first time. The new probe design uses a 3'-fluorescein-labeled probe and a 5'-Cy5-labeled probe that are in fluorescence energy transfer when hybridized to the same strand internal to an unlabeled primer set. Two hundred and fifty samples were genotyped for the C282Y and H63D hemochromatosis causing mutations by fluorescent melting curves. Multiplexing was performed by including two primer sets and two probe sets in a single tube. In clinically defined groups of 117 patients and 56 controls, the C282Y mutation was found in 87% (204/234) of patient chromosomes, and the relative penetrance of the H63D mutation was 2.4% of the homozygous C282Y mutation. Results were confirmed by restriction enzyme digestion and agarose gel electrophoresis. In addition, the probe covering the H63D mutation unexpectedly identified the A193T polymorphism in some samples. This method is amenable to multiplexing and has promise for scanning unknown mutations.

Alleles↗

Multiplex standardized RT-PCR for expression analysis of many genes in small samples.

Standardized RT-PCR (StaRT-PCR) enables numerical quantification as well as intra- and inter-laboratory comparison of gene expression. Multiplex StaRT-PCR, using two rounds of amplification, was conducted on Stratagene Universal Reference RNA. In the first round, cDNA, competitive template (CT) mix, and primers for up to 96 genes were amplified for varying numbers of cycles. Next, products from round one were diluted, combined with primers for one gene, and amplified for an additional 35 cycles. No additional cDNA or CT mix was added. Expression values obtained by uniplex and multiplex StaRT-PCRs were highly correlated (R=0.993, p<0.001). Products from round one could be diluted as much as 100,000-fold and still be quantified following round two amplification. Thus, using multiplex StaRT-PCR, 96 genes were measured in the same amount of cDNA typically used to measure one gene with uniplex StaRT-PCR. Multiplex StaRT-PCR was also used to measure 18 genes in the fine needle biopsy of a primary lung carcinoma.

Carcinoma, Non-Small-Cell Lung↗

Multiplex polymerase chain reaction for detection of herpes simplex virus type 1, type 2, cytomegalovirus, and varicella-zoster virus in ocular viral infections.

PURPOSE: To detect simultaneously herpes simplex virus type 1 (HSV-1), type 2 (HSV-2), cytomegalovirus (CMV), and varicella-zoster virus (VZV) in ocular specimens suspected of indicating viral infection, and to compare the results of multiplex polymerase chain reaction (PCR) with those of uniplex PCR. METHODS: Forty specimens, collected from 33 patients with clinically suspected herpes virus ocular infection, were tested. DNA was extracted from the specimens and amplified by multiplex and uniplex PCR. RESULTS: Both multiplex PCR and uniplex PCR gave the same results. Nineteen (19/33, 57.6%) patients were PCR-positive, among whom HSV-1 was detected in 13 (13/19, 68.4%) patients, and VZV in 6 (6/19, 31.6%) patients. CONCLUSION: These results demonstrated that multiplex PCR is as reliable as uniplex PCR, and is an accurate and a cost-saving method to identify several agents from a single specimen.

Adolescent↗

Detection of Thelohania solenopsae (Microsporidia: Thelohaniidae) in Solenopsis invicta (Hymenoptera: Formicidae) by multiplex PCR.

Oligonucleotide primer pairs were designed to unique areas of the small subunit (16S) rRNA gene of Thelohania solenopsae and a region of the Gp-9 gene of Solenopsis invicta. Multiplex PCR resulted in sensitive and specific detection of T. solenopsae infection of S. invicta. The T. solenopsae-specific primer pair only amplified DNA from T. solenopsae and T. solenopsae-infected S. invicta. This primer pair did not produce any amplification products from DNA preparations from uninfected S. invicta, seven additional species of microsporidia (including Vairimorpha invictae), or Mattesia spp. The Gp-9-specific primers recognized and amplified DNA from Solenopsis xyloni, Solenopsis richteri, Solenopsis geminata, the invicta/richteri hybrid, and monogyne and polygyne S. invicta, but not from T. solenopsae, and, as such, served as a positive control verifying successful DNA preparation. Multiplex PCR detected T. solenopsae in worker fire ants infected with as few as 5000 spores. Furthermore, multiplex PCR detected T. solenopsae in all developmental stages of S. invicta. However, detection could be made more sensitive by using only the T. solenopsae-specific primer pair; ants infected with as few as 10 spores were able to be discerned. Multiplex PCR detection of T. solenopsae offers the advantages of a positive control, a single PCR amplification, detection of all developmental stages, and increased sensitivity and specificity compared with microscopy.

Animals↗

Horner's syndrome associated with mononeuritis multiplex due to cytomegalovirus as the initial manifestation in a patient with AIDS.

We report on a 60-year-old male with AIDS who presented Horner's syndrome that was associated with mononeuritis multiplex due to cytomegalovirus (CMV) infection. This is the first case who presented Homer's syndrome in the course of AIDS. Horner's syndrome associated with mononeuritis multiplex in this patient was the initial manifestation without any opportunistic infections. Since Horner's syndrome and mononeuritis multiplex in the present case were both improved by ganciclovir, it is important to consider CMV infection when Horner's syndrome or mononeuritis multiplex is observed in immunocompromised patients, such as those with HIV-1 infection or AIDS, even if they do not show any other opportunistic infections.

AIDS-Related Opportunistic Infections↗

Multiplex polymerase chain reaction for microsatellite analysis of urine sediment cells: a rapid and inexpensive method for diagnosing and monitoring superficial transitional bladder cell carcinoma.

PURPOSE: Several urinary markers have been recently introduced in clinical practice for improving the noninvasive diagnosis of transitional cell carcinoma. Although microsatellite analysis must be considered the best method in terms of results, its cost and method time are unacceptable for daily use. We validated a more rapid and inexpensive method of determination using rapid DNA extraction and automatic multiplex polymerase chain reaction amplification. MATERIALS AND METHODS: A total of 120 patients who presented consecutively to a urological office, including 73 with transitional cell carcinoma and 43 who served as controls, were selected for study. Microsatellite analysis was performed in the blood/urine pair using 3 multiplex polymerase chain reactions per patient. Urine sediment inflammatory cells were assessed by urine dipstick test. Ten microsatellite loci were investigated. Numerical data collected during electrophoresis of the amplified segment in an ABI Prism 310 Genetic Analyzer were used to calculate the cutoff for allelic imbalance. Method sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: A total of 66 patients had microsatellite analysis alterations in urine sediment, of whom 59 had transitional cell carcinoma, while 7 had other urological diseases. Test sensitivity and specificity were 80.8% and 85.1%, respectively. Statistical analysis did not indicate any significant influence of inflammatory status on microsatellite analysis diagnostic performance. In the control group the allelic imbalance on chromosome 9 was significantly lower than on other chromosomes (p = 0.0143). This could confirm that chromosome 9 has a specific role in transitional cell carcinoma. The multiplex microsatellite analysis method was low cost and not time-consuming. CONCLUSIONS: Multiplex microsatellite analysis is a noninvasive, rapid, inexpensive and reproducible method for screening for and monitoring superficial transitional cell carcinoma. It should be considered an alternative method to urinary cytology and it should also be considered in the presence of urine sediment inflammatory cells.

Carcinoma, Transitional Cell↗

A multiplex polymerase chain reaction-based diagnostic method for bacterial vaginosis.

OBJECTIVE: To develop a polymerase chain reaction (PCR)-based diagnostic method for bacterial vaginosis using bacterial vaginosis-associated anaerobes. METHODS: A multiple PCR assay was developed using primers specific to 16S ribosomal deoxyribonucleic acid (DNA) (Mobiluncus mulieris and Mobiluncus curtisii), nanH (Bacteroides fragilis), and an internal spacer region of ribosomal DNA (Gardnerella vaginalis). The vaginal swabs from pregnant and nonpregnant women were examined by Gram stain-based Nugent scoring system. One hundred seventy-two samples of 853 Gram stain-interpretable samples were randomly selected and subjected to multiplex PCR assay. RESULTS: The sensitivity of the PCR assay ranged from 10 to 10 colony-forming units per vaginal swab. The prevalence of the bacterial vaginosis, intermediate, and normal categories was found by Nugent scoring system to be 21.6% (184/853), 26.0% (222/853), and 52.4% (447/853), respectively. By the multiplex PCR-based diagnostic method, 20.3% (35/172) of the samples were identified as bacterial vaginosis. The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of multiplex PCR in comparison with Gram stain examination were 78.4% (95% confidence interval [CI] 65.1%, 91.6%), 95.6% (95% CI 92.1%, 99.0%), 82.9% (95% CI 70.4%, 95.4%), and 94.2% (95% CI 90.3%, 98.1%), respectively. CONCLUSION: This multiplex PCR can be used as a diagnostic or screening test for bacterial vaginosis.

Adult↗

A multiplex PCR for simultaneous detection and differentiation of North American serotypes of bluetongue and epizootic hemorrhagic disease viruses.

In the present study, a multiplex RT-PCR-based assay for simultaneous detection and differentiation of North American serotypes of bluetongue (BT) virus (BTV) and epizootic hemorrhagic disease (EHD) virus (EHDV) in cell culture and clinical samples was developed. Two pairs of primers (B1 and B4) and (E1 and E4) were designed to hybridize to non-structural protein 1 (NS1) genomes of (BTV-11) and (EHDV-1), respectively. The multiplex PCR-based assay utilized a single tube-PCR amplification in which EHDV and BTV primers were used simultaneously in a multiplex format. The BTV primers generated a 790 base pair (bp) specific PCR product from RNA samples of North American BTV serotypes 2, 10, 11, 13 and 17; whereas EHDV serotypes 1 and 2 or total nucleic acid extract from non-infected baby hamster kidney (BHK) cells failed to demonstrate the 790bp specific BTV PCR product. Likewise, the EHDV primers produced a 387bp specific PCR product from RNA samples of EHDV serotypes 1 and 2, but not from BTV serotypes 2, 10, 11, 13, 17 or from total nucleic acid extract of BHK cell controls. Two pairs of nested primers (B2 and B3) and (E2 and E3), internal to the annealing sites of primers (B1and B4) and primers (E1 and E4), produced a 520bp specific BTV and a 224bp specific EHDV PCR product from BTV and EHDV first amplification products, respectively. These nested amplifications increased the sensitivity of the PCR assay and confirmed the specificity of the first amplified EHDV or BTV PCR products. The described multiplex RT-PCR-based assay could be used to facilitate rapid detection and differentiation of North American BTV and EHDV serotypes and to provide a valuable tool to study the epidemiology of these orbivirus infections in susceptible animal populations.

Animals↗

Development of a multiplex AmpliDet RNA for the simultaneous detection of Potato leafroll virus and Potato virus Y in potato tubers.

A novel isothermal multiplex AmpliDet RNA system is described for the simultaneous amplification and detection of Potato leafroll virus (PLRV) and Potato virus Y (PVY) in seed potatoes. The risk of contamination by carry-over during diagnostic screening is eliminated by performing the reaction in a single closed tube. The viruses present in a sample are identified using differently coloured molecular beacons directed to a selected virus-specific sequence within the amplicon formed during amplification. With this system, as little as 10 fg of purified PLRV or PVY can be detected. The presence of both viruses in a sample is detected by the multiplex assay within a high range of virus concentrations. The reliability of the multiplex assay was compared with the enzyme-linked immunosorbent assay for detection of PLRV- or PVY-antigens in potato tubers. The multiplex assay detected clearly the viruses present originally in the potato tubers in all samples, demonstrating its potential for routine diagnostic work and high-throughput screening.

Computer Systems↗

Detection and subtyping of swine influenza H1N1, H1N2 and H3N2 viruses in clinical samples using two multiplex RT-PCR assays.

A total of 360 type A swine influenza virus-positive samples including cell culture isolates, nasal swabs or lung tissues along with 30 virus-negative samples were tested for the detection and subtyping of H1N1, H1N2 or H3N2 by two multiplex reverse transcription (RT)-PCR assays. The positive samples had been collected between 1999 and 2001 from pigs with respiratory diseases, and type A influenza virus was isolated and subtyped by hemagglutination inhibition (HI) test at the Minnesota Veterinary Diagnostic Laboratory (MVDL). Two multiplex RT-PCR assays specific for H1 and H3, and N1 and N2 were developed. RT-PCR products with unique sizes characteristic of each subtype of influenza A virus were sequenced, and the sequences were demonstrated to be specific for H1N1, H1N2 or H3N2. Genomic RNAs or DNAs from 12 common swine pathogens other than type A influenza viruses were not amplified when the PCR assays were performed with these primer sets. Positive amplification reaction could be visualized with RNA extracted from up to 10(-5) dilution of each reference virus with original infectivity titer of 10(5) TCID(50)/ml. Of the 360 samples tested, swine influenza virus H1N1, H1N2 and H3N2 were identified in 200, 13 and 139 samples, respectively. The remaining eight samples were positive for both H1N1 and H3N2 viruses. The results of multiplex RT-PCR were 100% in agreement with those of virus isolation. These results demonstrate the usefulness of multiplex RT-PCR for detection and identification of influenza A virus subtypes. The results also indicate an increased occurrence of H1N2 in US swine population.

Animals↗

Simultaneous detection and identification of hepatitis A virus and rotavirus by multiplex nucleic acid sequence-based amplification (NASBA) and microtiter plate hybridization system.

Human rotavirus and hepatitis A virus (HAV) are two of the most common causes of virus-mediated food-borne illness. Epidemiological investigations of outbreaks associated with these viruses have been hindered by the lack of available methods for their detection in foodstuffs. In this study, a multiplex nucleic acid sequence-based amplification (NASBA) system was developed to detect specifically and simultaneously human rotavirus and HAV. Two sets of primers selected from published nucleic acid sequences were used in the NASBA mixture to amplify viral RNA from both viruses. Denaturing gel electrophoresis revealed two distinct RNA products with 268 and 474 nucleotides amplified from rotavirus and HAV, respectively. The specificity of the multiplex NASBA was confirmed by a microtiter plate hybridization and detection system and by Northern blot analysis using specific oligonucleotide probes. The presence of non-homologous nucleic acid and non-target microorganisms did not have any effect on the specificity of the multiplex NASBA. Using the optimized NASBA and microtiter plate hybridization conditions, as little as 400 PFU ml x (-1) of HAV and 40 PFU ml x (-1) of rotavirus were detected. The multiplex NASBA system offers advantages over monoplex virus detection systems in terms of turnaround time and cost-effectiveness.

Biotinylation↗

Differentiation between porcine epidemic diarrhea virus and transmissible gastroenteritis virus in formalin-fixed paraffin-embedded tissues by multiplex RT-nested PCR and comparison with in situ hybridization.

Porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV) were detected and differentiated in formalin-fixed, paraffin-embedded tissues from experimentally and naturally infected pigs by multiplex reverse transcription-nested polymerase chain reaction (RT-nPCR). The results of this new method were compared with in situ hybridization. A method based on xylene deparaffinization followed by proteinase K digestion yielded RNA of a suitable quality for reliable and consistent multiplex RT-nPCR analyses. PEDV and TGEV cDNAs were detected in jejunal tissues from experimentally and naturally infected pigs by multiplex RT-nPCR. Distinct positive signals for PEDV and TGEV were also detected in the same jejunal tissues by in situ hybridization. The rate of conformity between multiplex RT-nPCR and in situ hybridization was 100% for the detection of PEDV and TGEV in formalin-fixed paraffin-embedded jejunal tissues.

Animals↗

Detection of pathogenic bacteria in shellfish using multiplex PCR followed by CovaLink NH microwell plate sandwich hybridization.

Outbreak of diseases associated with consumption of raw shellfish especially oysters is a major concern to the seafood industry and public health agencies. A multiplex PCR amplification of targeted gene segments followed by DNA-DNA sandwich hybridization was optimized to detect the etiologic agents. First, a multiplex PCR amplification of hns, spvB, vvh, ctx and tl was developed enabling simultaneous detection of total Salmonella enterica serotype Typhimurium, Vibrio vulnificus, Vibrio cholerae and Vibrio parahaemolyticus from both pure cultures and seeded oysters. Amplicons were then subjected to a colorimetric CovaLink NH microwell plate sandwich hybridization using phosphorylated and biotinlylated oligonucleotide probes, the nucleotide sequences of which were located internal to the amplified DNA. The results from the hybridization with the multiplexed PCR amplified DNA exhibited a high signal/noise ratio ranging between 14.1 and 43.2 measured at 405 nm wavelength. The sensitivity of detection for each pathogen was 10(2) cells/g of oyster tissue homogenate. The results from this study showed that the combination of the multiplex PCR with a colorimetric microwell plate sandwich hybridization assay permits a specific, sensitive, and reproducible system for the detection of the microbial pathogens in shellfish, thereby improving the microbiological safety of shellfish to consumers.

Animals↗

Detection of total and hemolysin-producing Vibrio parahaemolyticus in shellfish using multiplex PCR amplification of tl, tdh and trh.

Vibrio parahaemolyticus is an important human pathogen which can cause gastroenteritis when consumed in raw or partially-cooked seafood. A multiplex PCR amplification-based detection of total and virulent strains of V. parahaemolyticus was developed by targeting thermolabile hemolysin encoded by tl, thermostable direct hemolysin encoded by tdh, and thermostable direct hemolysin-related trh genes. Following optimization using oligonucleotide primers targeting tl, tdh and trh genes, the multiplex PCR was applied to V. parahaemolyticus from 27 clinical, 43 seafood, 15 environmental, 7 strains obtained from various laboratories and 19 from oyster plants. All 111 V. parahaemolyticus isolates showed PCR amplification of the tl gene; however, only 60 isolates showed amplification of tdh, and 43 isolates showed amplification of the trh gene. Also, 18 strains showed amplification of the tdh gene, but these strains did not show amplification of the trh gene. However, one strain exhibited amplification for the trh but not the tdh gene, suggesting both genes need to be targeted in a PCR amplification reaction to detect all hemolysin-producing strains of this pathogen. The multiplex PCR approach was successfully used to detect various strains of V parahaemolyticus in seeded oyster tissue homogenate. Sensitivity of detection for all three target gene segments was at least between 10(1)-10(2) cfu per 10 g of alkaline peptone water enriched seeded oyster tissue homogenate. This high level of sensitivity of detection of this pathogen within 8 h of pre-enrichment is well within the action level (10(4) cfu per 1 g of shell stock) suggested by the National Seafood Sanitation Program guideline. Compared to conventional microbiological culture methods, this multiplex PCR approach is rapid and reliable for accomplishing a comprehensive detection of V. parahaemolyticus in shellfish.

Animals↗

Individuals from multiplex insulin-dependent diabetes mellitus (IDDM) families express higher levels of TCRBV2S1 than controls.

T lymphocytes recognise peptide antigens through the T cell antigen receptor, which is composed of variable alpha and beta chains. There are forty-six functional variable regions on the beta chain. In this study the expression of the T cell receptor beta-chain variable regions 2S1 and 3S1, in a large cohort of multiplex insulin-dependent diabetes mellitus families, have been determined by use of monoclonal antibodies and flow cytometry. Peripheral blood was collected from these multiplex families and three control groups, healthy individuals, sporadic insulin-dependent diabetes mellitus patients and non-insulin-dependent diabetes mellitus patients. The level of TCRBV2S1 expression in the multiplex families was significantly higher than all the control groups for both the CD4+ and CD8+ T lymphocyte subsets. Detailed analysis of the family data showed that this increased expression was not associated with age, sex, HLA type or the diabetic phenotype. The TCRBV3S1 expression in all the diabetic cohorts was significantly lower than the healthy controls, in the CD4 subset only. Detailed analysis of the family data showed only the fathers TCRBV3S1 expression was lower than the healthy controls. This study gives further insight into TCRBV usage which could reflect the mechanism of the autoimmune response in IDDM multiplex families.

Adolescent↗

Implications of a common polymorphism in intron 12 of the dystrophin gene for deletion detection by multiplex PCR.

The multiplex polymerase chain reaction (PCR) is a reliable and efficient method for detecting dystrophin gene deletions in about 65% of patients with Duchenne or Becker muscular dystrophy (DMD or BMD). The 9-plex PCR assay, which simultaneously amplifies the muscle-specific promoter and exons 3, 6, 13, 43, 47, 50, 52 and 60, is one of the multiplex PCR assays used routinely to test for DMD and BMD deletions. In this study, we describe a previously unrecognized A to G base variation in intron 12 (nt -110 from exon 13) of the dystrophin gene. This variant, located within the annealing site of the exon 13 forward primer, prevented amplification of exon 13 in the 9-plex PCR assay. Present in 56% (25 of 45) of normal Caucasian alleles and 23% (3 of 13) of normal black American alleles, it is likely encountered frequently during dystrophin deletion analysis by multiplex PCR, and may complicate test result interpretation. Therefore, we suggest two modifications for the multiplex PCR detection of dystrophin gene deletion.

Alleles↗

Validation and casework application of a Y chromosome specific STR multiplex.

A series of validation experiments was performed for a Y chromosome specific STR multiplex system following the suggestions made by the Technical Working Group DNA Analysis Methods (TWGDAM). The multiplex PCR products were detected on Perkin-Elmer 373 and 377 automated sequencers using two labeling colors. No problems regarding the stability, robustness and sensitivity of the Y STR multiplex were observed. Mixture studies revealed a cut off rate similar to autosomal STRs for mixtures of male DNAs and no interference of any female admixture. The comparison of the Y STR results to the autosomal typing results for 56 nonprobative semen stains and swabs, showed a slightly higher success rate in detecting the semen donor's alleles for the Y STR multiplex. Two examples are shown to illustrate the usefulness of Y STR typing for DNA mixtures. In one case the Y STR results confirmed an isolated exclusion; in the other case, the interpretation of a mixture was clarified since the Y STR results proved the presence of DNA from at least two semen donors. Y STR typing is a valuable addition to the forensic DNA testing panel.

Alleles↗