Strand-specific, real-time RT-PCR assays for quantification of genomic and positive-sense RNAs of the fish rhabdovirus, Infectious hematopoietic necrosis virus

Journal of Virological Methods
By: , and 

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Abstract

The fish rhabdovirus, Infectious hematopoietic necrosis virus (IHNV), is an important pathogen of salmonids. Cell culture assays have traditionally been used to quantify levels of IHNV in samples; however, real-time or quantitative RT-PCR assays have been proposed as a rapid alternative. For viruses having a single-stranded, negative-sense RNA genome, standard qRT-PCR assays do not distinguish between the negative-sense genome and positive-sense RNA species including mRNA and anti-genome. Thus, these methods do not determine viral genome copy number. This study reports development of strand-specific, qRT-PCR assays that use tagged primers for enhancing strand specificity during cDNA synthesis and quantitative PCR. Protocols were developed for positive-strand specific (pss-qRT-PCR) and negative-strand specific (nss-qRT-PCR) assays for IHNV glycoprotein (G) gene sequences. Validation with synthetic RNA transcripts demonstrated the assays could discriminate the correct strand with greater than 1000-fold fidelity. The number of genome copies in livers of IHNV-infected fish determined by nss-qRT-PCR was, on average, 8000-fold greater than the number of infectious units as determined by plaque assay. We also compared the number of genome copies with the quantity of positive-sense RNA and determined that the ratio of positive-sense molecules to negative-sense genome copies was, on average, 2.7:1. Potential future applications of these IHNV strand-specific qRT-PCR assays are discussed.

Publication type Article
Publication Subtype Journal Article
Title Strand-specific, real-time RT-PCR assays for quantification of genomic and positive-sense RNAs of the fish rhabdovirus, Infectious hematopoietic necrosis virus
Series title Journal of Virological Methods
DOI 10.1016/j.jviromet.2005.08.017
Volume 132
Issue 1-2
Year Published 2006
Language English
Publisher Elsevier
Contributing office(s) Western Fisheries Research Center
Description 7 p.
First page 18
Last page 24
Online Only (Y/N) N
Additional Online Files (Y/N) N
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