Journal: Viruses
Article Title: Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) including Variant Analysis by Mass Spectrometry in Placental Tissue
doi: 10.3390/v14030604
Figure Lengend Snippet: Workflow and molecular principle of SARS-CoV-2 RNA detection in FFPE tissue by MALDI-TOF mass spectrometry. RNA extraction from FFPE placental and amniotic tissue was performed using the Maxwell RSC RNA FFPE Kit (Promega) according to manufacturer’s instructions. Extracted viral RNA is then reverse transcribed into cDNA and amplified by a one-step RT-PCR reaction. The figure schematically depicts specific amplification of the SARS-CoV-2 targets N1 and N2. The forward primers are indicated in green, the reverse primers in blue. Thereafter, PCR products are treated with the shrimp alkaline phosphatase (SAP) enzyme to remove unincorporated nucleotides (dNTPs). Next, a single nucleotide extension reaction is performed, in which target-specific extension primers are elongated by a single mass-modified terminator nucleotide (A, T, C or G) complementary to the cDNA template sequence. The extension products (EP) are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) using the MassARRAY system (Agena Bioscience) and mass spectra of the SARS-CoV-2-specific detected cDNA fragments are generated. In the absence of viral RNA, RT-PCR as well as single nucleotide extension reactions cannot be performed and consequently, no cDNA fragments are detected by MALDI-TOF analysis. EP: extension product; UEP: unextended extension primer.
Article Snippet: The resultant extension products (analytes) are then desalted, transferred to a silicon chip with pre-spotted matrix material (SpectroCHIP ® Array), and loaded onto the MALDI-TOF mass spectrometer (MassARRAY Analyzer 4, Agena Bioscience).
Techniques: RNA Detection, Mass Spectrometry, RNA Extraction, Reverse Transcription, Amplification, One Step RT-PCR, Modification, Sequencing, Generated, Reverse Transcription Polymerase Chain Reaction