Journal: PLoS Pathogens

Article Title: The RNA helicase DDX5 promotes viral infection via regulating N 6 -methyladenosine levels on the DHX58 and NFκB transcripts to dampen antiviral innate immunity

doi: 10.1371/journal.ppat.1009530

Figure Lengend Snippet: (A, B): m6A methylation of transcripts was detected by m6A qRT-PCR in DDX5-knockdown or DDX5 overexpressed MEFs after VSV infection. MEFs were transfected with DDX5 siRNA (siNC) for 48hand infected with VSV for 6h (A), and MEFs were transfected with Myc-DDX5 expressed vector (DDX5) or Myc tag control vector (Con) for 24h and infected with VSV for 6h (B). After extracting total RNA, purifying mRNA, and removing ribosomal RNA, purified mRNA was fragmented and incubated with anti-rabbit m6A or anti-rabbit IgG-conjugated dynabeads for 4h. RNA was isolated from the solution with phenol-chloroform, and cDNA was subjected to qRT-PCR using GAPDH, TBK1, DHX58, IKKγ, and p65 primers. Results are presented relative to those obtained with NC or control groups, and the expression of all the indicated proteins was analyzed using western blotting. (C, D): The interaction between METTL3 and transcripts was detected through METTL3 RIP qRT-PCR in knockdown-DDX5 (C) or DDX5-expressing (D) MEFs after VSV infection. MEFs were transfected with DDX5 siRNA (siNC) for 48 h and infected with VSV for 6 h (C), and transfected with DDX5 expression plasmid (DDX5) or control vector (Con) for 24 h, infected with VSV for 6h, and subjected to METTL3 RIP qRT-PCR to detect GAPDH, TBK1, DHX58, IKKγ, and p65. Results are presented relative to those obtained with NC or control groups, and the expression of all the indicated proteins was analyzed using western blotting. (E, F): Nuclear transcript retention increased in DDX5-knockdown MEFs. MEFs were transfected with DDX5 siRNA (siNC), infected with VSV for 8h, and lysed to extract nuclear to cytoplasmic RNA fractions. Then, RNA was used to analyze m6A modified DHX58, IKKγ, and p65 mRNA by m6A qRT-PCR (E) with RNU6 and GAPDH as the nuclear and cytoplasmic controls, respectively. The quantitative distribution of m6A modified DHX58, IKKγ, and p65 mRNAs in DDX5-knockdown MEFs were detected by m6A qRT-PCR (F). (G, H): Nuclear transcript export was increased in DDX5-expressing MEFs. MEFs were transfected with DDX5 expression plasmid (control vector), infected with VSV for 8h, and lysed to extract nuclear or cytoplasmic RNA; then, RNA was used to analyze m6A modified DHX58, IKKγ, and p65 mRNA by m6A qRT-PCR (G), and the quantitative distribution of these mRNAs was detected by m6AqRT-PCR (H). (I, J) : Immunoblot analysis of DHX58, IKKγ, and p65 in DDX5-knockdownMEFs (I) or DDX5-expressing MEFs (J) after infection with VSV at 0, 4, and 6 h. All data are mean ± SEM of biologically independent samples. Data are representative of three independent experiments. ns, no significant difference. * p <0.05, ** p <0.01, and *** p <0.001 (Student’s t -test).

Article Snippet: Biotin-labeled RNA was detected and visualized according to the instructions of the chemiluminescent nuclei acid detection module (Thermo Fisher, 89880), the biotin-unlabeled RNA was acquired according to the biotin-labeled protein–RNA complex blotting, and mRNAs were purified with the Dynabeads mRNA Purification Kit (Invitrogen, 61006).

Techniques: Methylation, Quantitative RT-PCR, Infection, Transfection, Plasmid Preparation, Purification, Incubation, Isolation, Expressing, Western Blot, Modification

Journal: PLoS Pathogens

Article Title: The RNA helicase DDX5 promotes viral infection via regulating N 6 -methyladenosine levels on the DHX58 and NFκB transcripts to dampen antiviral innate immunity

doi: 10.1371/journal.ppat.1009530

Figure Lengend Snippet: (A): m6A methylation of transcripts was detected in DDX5 +/+ or DDX5 +/- primary mouse macrophages infected for 8 h with VSV (MOI = 10). After extracting total RNA and purifying mRNA, mRNA was used to perform m6A qRT-PCR by incubating with anti-rabbit m6A or anti-rabbit IgG-conjugated dynabeads for 4 h. RNA was isolated and subjected to qRT-PCR using GAPDH, TBK1, DHX58, IKKγ, and p65 primers. Results are presented relative to those obtained in the control group, and the expression of DDX5 was analyzed bywestern blotting. (B): Immunoblot analysis of DDX5, DHX58, p65, and IKKγ in lysates of DDX5 +/+ or DDX5 +/- mouse macrophages infected for 0, 4, and 8 h with VSV (MOI = 10). (C, D): ELISA of IFN-β (C) and IL-6 (D) in cell supernatants ofDDX5 +/+ or DDX5 +/- mouse macrophages infected for 0, 4, and 8 h with VSV (MOI = 10). (E, F): ELISA of IFN-β (E) and IL-6 (F) in serum after DDX5 +/+ or DDX5 +/- mice were intraperitoneally injected with PBS or VSV (5×10 8 plaque-forming units/g body weight) for 8h (n = 6). (G, H): ELISA of IFN-β (G) and IL-6 (H) in serum after DDX5 +/+ or DDX5 +/- mice were intraperitoneally injected with PBS or SeV (1×10 8 plaque-forming units/g body weight) for 8h (n = 6). (I, J): The TCID 50 dose of VSV (I) or SeV (J) was measured in lungs, liver, and spleen of DDX5 +/+ or DDX5 +/- mice. (K): Pathological lesions in lungs, liver, and spleen of DDX5 +/+ or DDX5 +/- mice observed by hematoxylin-eosin staining with intraperitoneal injection of PBS, VSV (5×10 8 plaque-forming units/g body weight) or SeV (1×10 8 plaque-forming units/g body weight) for 12h. Scale bars, 100 μm. All data are presented as mean ± SEM of biologically independent samples. n = number of biological replicates. Data are representative of three independent experiments. NS, no significant difference. ** p <0.01, *** p <0.001 (Student’s t -test).

Article Snippet: Biotin-labeled RNA was detected and visualized according to the instructions of the chemiluminescent nuclei acid detection module (Thermo Fisher, 89880), the biotin-unlabeled RNA was acquired according to the biotin-labeled protein–RNA complex blotting, and mRNAs were purified with the Dynabeads mRNA Purification Kit (Invitrogen, 61006).

Techniques: Methylation, Infection, Quantitative RT-PCR, Isolation, Expressing, Western Blot, Enzyme-linked Immunosorbent Assay, Injection, Staining

Journal: medRxiv

Article Title: COVID-19 Diagnostic Testing For All - Using Non-Dilutive Saliva Sample Collection, Stabilization and Ambient Transport Devices

doi: 10.1101/2021.01.20.20243782

Figure Lengend Snippet: Gamma-irradiated SARS-CoV-2 virus (BEI Resources) at 2 genome equivalents/uL was spiked in 1mL of saliva kept either in non-GTR STM (“Saliva”) (open circles) or GTR-STM devices (open diamonds), extracted with MagMAX Viral RNA Kit (ThermoFisher) and RT-PCR performed with CDC’s N1 primer. The pass/fail criteria set at 35.7 CT is 3 CT values more than the average CT value of the “Saliva” only samples. “Saliva” samples without GTR-STM gave a mean CT of 32.4 CT (Std Dev, ±0.3), and Saliva Samples in GTR-STM gave a mean CT of 32.7 CT (Std Dev, ±0.2). Study setup Experimental Sample : A contrived GTR-STM sample (n=9) was prepared by spiking 1mL of saliva with 2 genome equivalents/uL of -gamma-irradiated SARS-CoV-2 virus. Control sample : A contrived non-GTR STM (“Saliva”) (n=3) sample was prepared by spiking 1mL of saliva with 2 genome equivalents/uL of gamma-irradiated SARS-CoV-2 virus. Sample Extraction :RNA was extracted from 200uL of sample from both control and stressed samples following manufacturer’s instructions for MagMAX Viral RNA (ThermoFisher) manual protocol and eluted with 50uL of elution buffer. Quantification : Amplify 5uL of extracted RNA from each sample in triplicates with TaqPath master mix (ThermoFisher) and CDC’s N1 Primer (IDT).

Article Snippet: GTR-STM was tested by extraction with either QIAamp Viral RNA Mini Kit (Qiagen, cat #52906) or MagMAX Viral RNA Isolation Kit (ThermoFisher, cat #AM1939) and compared with either PBS or neat saliva as controls.

Techniques: Irradiation, Reverse Transcription Polymerase Chain Reaction

Journal: medRxiv

Article Title: COVID-19 Diagnostic Testing For All - Using Non-Dilutive Saliva Sample Collection, Stabilization and Ambient Transport Devices

doi: 10.1101/2021.01.20.20243782

Figure Lengend Snippet: Heat-inactivated SARS-CoV-2 virus RNA (BEI Resources) at 500 genome equivalents/uL was spiked into 1mL of saliva kept either in GTR-STM collection devices or non-GTR-STM (“Saliva”) tubes, and stored at 25°C for 36 days. Matched spiked control saliva samples in both kinds of tubes were stored at -80°C. The pass/fail criteria are set at 32 CT value. 200uL of the sample is used at each time point to extract viral RNA with the MagMAX kit with a final elution volume of 50uL. The CT value of the viral RNA extracted with MagMAX viral RNA kit is normalized to input volume of 200uL (volume of sample used for RNA extraction). All GTR-STM samples gave excellent recoveries when compared to their matched -80°C control. Both the -80°C and the 25°C samples for the non-GTR-STM (“Saliva”) is above the pass/fail line even in the -80°C control samples indicating that the viral RNA is degraded by the Rnase in the short time (less than half hour) that the saliva sample is defrosting before RNA extraction is performed. Study setup Experimental Samples : 1 mL aliquots of saliva contrived with SARS-CoV-2 at 500 genome equivalents/uL (BEI Resources) were placed into either GTR-STM devices or non-GTR-STM (“Saliva”) tubes and stored at ambient (25°C) for up to 36 days. Control sample : 1 mL aliquots of saliva contrived with SARS-CoV-2 at 500 genome equivalents/uL (BEI Resources) were placed into either GTR-STM devices or non-GTR-STM (“Saliva”) tubes and stored at -80°C for up to 36 days. Sample Extraction : RNA extracted from 200uL of experimental and control samples with MagMAX viral RNA kit at days 10, 15, 20, 25, and 36 and eluted in 50uL of elution buffer. Quantification : 5uL of RNA was quantified with CDC’s SARS-CoV-2 RT-qPCR assay for N1 primer.

Article Snippet: GTR-STM was tested by extraction with either QIAamp Viral RNA Mini Kit (Qiagen, cat #52906) or MagMAX Viral RNA Isolation Kit (ThermoFisher, cat #AM1939) and compared with either PBS or neat saliva as controls.

Techniques: RNA Extraction, Quantitative RT-PCR

Journal: Biotechniques

Article Title: Improved SARS-CoV-2 PCR detection and genotyping with double-bubble primers

doi: 10.2144/btn-2021-0063

Figure Lengend Snippet: (A–C) Dose–response curves using double-bubble primer mix #8 and VIC-TqM probe #12 and decimal dilutions of SARS-CoV-2 synthetic RNA N. (A) Real-time amplification plot. C t values: 8 × 10 5 copies, 22.82; 8 × 10 4 copies, 26.27; 8 × 10 3 copies, 30.55; 8 × 10 2 copies, 32.51. (B) 5% agarose gel of the PCR amplification products. Lane 1: ultra-low-range ladder; lanes 2–5: 139-bp amplicons of 8 × 10 5 to 8 × 10 2 RNA copies per tube. Also included in the PCR reaction mix were 2× TqM buffer without UDP and iScript reverse-transcriptase. (C) Efficiency plot of the PCR reaction depicted in panel A. Slope = -3.3359 represents PCR reaction efficiency of 99.42%; R 2 = 0.9816. (D) One-tube RT-qPCR using double-bubble primer mix #10 from region 2 using SARS-CoV-2 synthetic RNA (2 × 10 4 copies per tube) and FAM-TqM probe #13. RT-qPCR was performed with standard conditions.

Article Snippet: For cDNA synthesis, iScript reverse-transcriptase kit was employed: 25°C, 5 min, 42°C, 15 min 95°C, 1 min, 4°C hold (BioRad, 1708891).

Techniques: Amplification, Agarose Gel Electrophoresis, Reverse Transcription, Quantitative RT-PCR

Journal: Biotechniques

Article Title: Improved SARS-CoV-2 PCR detection and genotyping with double-bubble primers

doi: 10.2144/btn-2021-0063

Figure Lengend Snippet: (A) qPCR using reverse-transcribed cDNA template and double-bubble (D-B) primer mix #10, FAM-TqM probe #13, TqM fast kit+ uracil-DNA glycosylase (UDG) assayed in duplicates. Insert depicts 5% agarose gel; lane 1: ultra-low-range (ULR) ladder; lanes 2 & 3: template cDNA; lanes 4 & 5: non-template control (NTC). C t average values: cDNA, 28.60; NTC, undetermined. (B) One-tube RT-qPCR using SARS-CoV-2 synthetic RNA N template and D-B primer mix #8, VIC-TqM probe #12, TqM fast kit without UDG iScript reverse transcriptase, assayed in duplicate. Insert depicts 5% agarose gel; lane 1: ULR ladder; lanes 2 and 3: template RNA; lanes 4 and 5: NTC. C t average values: RNA, 24.63, NTC, undetermined. (C) Duplex qPCR using SARS-CoV-2 synthetic RNA N template and TqM fast kit with UDG. C t values: primer 8, 26.13; primer 10, 32.19; duplex primers 8 + 10, 26.36 and 30.27, respectively; NTC, undetermined. (D) 5% agarose gel of samples shown in panel C. Lane 1: ULR ladder; lane 2: primer D-B mix #8 (amplicon 139 bp); lane 3: D-B primer mix #10 (amplicon 158 bp); lane 4: duplex of both primers #8 and #10 (amplicons 139 and 158 bp). Arrows (C & D) show duplex amplifications in the same tube with D-B primers #8 and #10. PCR was performed using fast conditions with 40 (A, C & D) and 30 (B) cycles.

Article Snippet: For cDNA synthesis, iScript reverse-transcriptase kit was employed: 25°C, 5 min, 42°C, 15 min 95°C, 1 min, 4°C hold (BioRad, 1708891).

Techniques: Reverse Transcription, Agarose Gel Electrophoresis, Control, Quantitative RT-PCR, Amplification

Journal: Biotechniques

Article Title: Improved SARS-CoV-2 PCR detection and genotyping with double-bubble primers

doi: 10.2144/btn-2021-0063

Figure Lengend Snippet: The reaction mixture contained hot-start double-bubble (D-B) primer mix #4, VIC-TqM probe #12, cost-effective non-hot-start Taq polymerase (FroggaBio), reverse transcriptase (iScript), synthetic SARS-CoV-2 RNA gene N as template, added dNTPs and ROX dye for internal calibration. The reaction was assembled at room temperature and subjected to real time RT-qPCR using the following fast conditions: 42°C, 15 min; 95°C,1 min; 30 cycles of 95°C, 1 s → 70°C, 20 s. The amplification plot and (insert) 5% agarose gel depict the amplification of SARS-CoV-2 RNA extracted from the nasopharyngeal swabs of patient S1 (lane 2) and negative patient N1 (lane 3), no-template controls (lanes 4 and 5) and SARS-CoV-2 gene N synthetic RNA as positive control (lane 6). Note the amplification in the real-time plot and the 115-bp band in the 5% agarose gel with SARS-CoV-2 virus or synthetic RNA (lanes 2 and 6), with no amplifications in the negative control N1 (lane 3) or NTC (lanes 4 and 5). Lane 1: ultra-low-range ladder. C t values: positive patient S1: 23.95; synthetic RNA: 23.84; negative patient N1 and NTC: undetermined.

Article Snippet: For cDNA synthesis, iScript reverse-transcriptase kit was employed: 25°C, 5 min, 42°C, 15 min 95°C, 1 min, 4°C hold (BioRad, 1708891).

Techniques: Reverse Transcription, Quantitative RT-PCR, Amplification, Agarose Gel Electrophoresis, Positive Control, Virus, Negative Control