virology research

Barking Up the Right Tree: Using NanoLuc to Screen for Canine Distemper Antivirals

Posted on by Natalie Larsen

Canine distemper virus (CDV) is a highly contagious pathogen that is the etiological agent responsible for canine distemper (CD), a systemic disease that affects a broad spectrum of both domestic dogs and wild carnivores. While there are commercially available vaccines for CDV that can provide immunity in vivo and protect canines from contracting CD, there is a strong demand for effective canine distemper antivirals to combat outbreaks. Such drugs remain unavailable to date, largely due to the laborious, time-consuming nature of methods traditionally used for high-throughput drug screening of anti-CDV drugs in vitro. In a recent study published in Frontiers in Veterinary Science, researchers demonstrated a new tool for rapid, high-throughput screening of anti-CDV drugs: a NanoLuc® luciferase-tagged CDV.

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The Path Brightens for Vaccine Researchers: Luminescent Reporter Viruses Detect Neutralizing Antibodies

Posted on by Michele Arduengo

Developing a vaccine that is safe, effective, easily manufactured and distributed is a daunting task. Yet, that is exactly what is needed in response to the COVID-19 pandemic.

Computer generated 3D image of coronavirus

Vaccine development, safety and efficacy testing take time. The mumps vaccine is thought to be the quickest infectious disease vaccine ever produced, and its development required four years from sample collection to licensing (2). However, there are many reasons to anticipate quicker development for a COVID-19 vaccine: Researchers are collaborating in unprecedented ways, and most COVID-19 scientific publications are free for all to access and often available as preprints. As of August 11, 2020, researchers around the globe have more than 165 vaccine candidates in development, 30 of which are in some phase of human clinical trials (1). The range of vaccine formulations available to scientists has expanded to include RNA and DNA vaccines, replication-defective adenovirus vaccines, inactivated or killed vaccines and subunit protein vaccines. Equally important is that vaccine developers and researchers have greater access to powerful molecular biology tools like bioluminescent reporters that enable quicker testing and development.

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In Vitro Transcription and the Use of Modified Nucleotides

Posted on by Leah Cronan
In vitro transcription
RNA polymerase unwinds DNA strands for transcription.

Transcription is the production of RNA from a DNA sequence. It’s a necessary life process in most cells. Transcription performed in vitro is also a valuable technique for research applications—from gene expression studies to the development of RNA virus vaccines.

During transcription, the DNA sequence is read by RNA polymerase to produce a complimentary, antiparallel RNA strand. This RNA strand is called a primary transcript, often referred to as an RNA transcript. In vitro transcription is a convenient method for generating RNA in a controlled environment outside of a cell.

In vitro transcription offers flexibility when choosing a DNA template, with a few requirements. The template must be purified, linear, and include a double stranded promoter region. Acceptable template types are plasmids or cloning vectors, PCR products, synthetic oligos (oligonucleotides), and cDNA (complimentary DNA). 

In vitro transcription is used for production of large amounts of RNA transcripts for use in many applications including gene expression studies, RNA interference studies (RNAi), generation of guide RNA (gRNA) for use in CRISPR, creation of RNA standards for quantification of results in reverse-transcription quantitative PCR (RT-qPCR), studies of RNA structure and function, labeling of RNA probes for blotting and hybridization or for RNA:protein interaction studies, and preparation of specific cDNA libraries, just to name a few!

In vitro transcription can also be applied in general virology to study the effects of an RNA virus on a cell or an organism, and in development and production of RNA therapeutics and RNA virus vaccines. The large quantity of viral RNA produced through in vitro transcription can be used as inoculation material for viral infection studies. Viral mRNA transcripts, typically coding for a disease-specific antigen, can be quickly created through in vitro transcription, and used in the production of vaccines and therapeutics.

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Zika Virus: Another RNA Virus Emerges

Posted on by Isobel Maciver
no mosquito

Zika virus has been in the news recently due to growing concerns about its global spread. If you have never heard of Zika virus before, you are not alone. Although first discovered in the 1940s, Zika has not been the subject of much study as infection is considered rare and the symptoms mild. However, all this has changed in recent months due to the rapid spread of the virus in Latin America, where it has been associated with an increased incidence of microcephaly, a severe birth defect where babies are born with underdeveloped brains. Although the connection of Zika with microcephaly is not yet proven, the circumstantial evidence is strong, leading the World Health Organization to declare the spread of Zika virus an international public health emergency earlier this week.

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Screening for Antiviral Compounds under Level 4 Containment Conditions

Posted on by Isobel Maciver

Working with bacteria and viruses that cause life-threatening diseases with no currently available treatment options takes guts. Most scientists are familiar with the routine requirements of good aseptic technique, are highly aware of laboratory safety requirements, and are more than familiar with autoclaves and sterilization issues, but if we make a mistake the consequences are usually only lost time or a spoiled experiment—not a lost life.

Scientists working with highly virulent organisms deal with a whole other level of risk that requires adherence to the strictest of safety regulations, and these containment regulations can sometimes place constraints on the type of experiment that can be performed with dangerous pathogens. A paper published in the April 2014 issue of Assay and Drug Development Technologies brought this to my attention and reminded me of the serious issues some scientists face on a daily basis as they research ways to combat infectious diseases.

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