Glossary of terms

Below is a list of terms used on this site and elsewhere in relation to RNA interference. Please contact us if you would like to suggest any additions to this list.

AAV Adeno-associated virus - a small virus commonly used as a vector in gene therapy
adenovirus A medium-sized dsRNA virus first isolated from human adenoids
anti-sense RNA or DNA sequence synthesized to be complementary to the normal or 'sense'  mRNA sequence
cytoplasm The part of the cell containing the organelles and excludes the nucleus
ddRNAi DNA-directed RNA interference – RNAi expressed from a DNA construct. Benitec Biopharma's patented technology. shRNA is an example of ddRNAi.
ddRNAi therapeutics Human therapeutics based on ddRNAi, Benitec Biopharma's patented process
Dicer An enzyme in the cell's cytoplasm that cuts dsRNA into double stranded small interfering (si)RNA molecules 20-25 nucleotides long.
DNA Deoxyribonucleic acid – the chemical that comprises the genetic blueprint for all organisms (except RNA viruses)
DNA cassette A fragment of DNA carrying and capable of expressing one or more DNA sequences coding for RNA sequences of interest
DNA construct A synthesized segment of DNA to be transplanted (or transfected) into the DNA of another cell
dsRNA double stranded RNA – two sequences of RNA that are complementary to each other. dsRNA usually only occurs in cells as part of RNA interference
genes Those stretches of DNA that code for proteins or RNA sequences; genes are the organism's unit of heredity
gene cassette A manipulable fragment of DNA carrying and capable of expressing, one or more genes of interest
gene silencing The knocking down of a gene so that its usual product e.g. a protein, is not formed
gene therapy Use of introduced DNA to replace a mutated gene, to correct a mutation or code for a therapeutic protein
genetic disease A illness or condition caused by abnormalities in genes or chromosomes; may be both heritable and non-heritable
guide strand The strand from unwound siRNA which binds to RISC in RNAi. The other strand (the passenger) is degraded..
immune activation Activation of the immune (defence) response by the cell
lentivirus A virus often used as a gene therapy vehicle to introduce DNA into target cells
mRNA messenger RNA - a molecule of RNA which is transcribed from DNA and is translated into a protein
NSCLC non-small cell lung cancer  - a type of epithelial lung cancer which is relatively insensitive to chemotherapy, compared to small cell carcinoma
nucleotides The structural units of DNA and RNA, made up of a nitrogenous base, a 5 carbon sugar and a phosphate group
nucleus The part of the cell that is not the cytoplasm in eukaryotes; the lack of nucleus is a key marker of procaryotes which only have cytoplasm
off target effects The switching off of unintended gene functions as a result of gene silencing
opiod infusion Infusion of opioids (e.g. morphine) for pain management usually in terminal patients
OPMD oculopharyngeal muscular dystrophy - a rare, slow progressing, degenerative disease muscle disorder;  characterized by progressive eyelid drooping  and swallowing difficulties.
passenger strand The strand from unwound siRNA in RNAi which is degraded; the other (the guide strand) binds to the RISC
polyethylenimine PEI - a polymeric chemical used to deliver DNA into target cells
RNAi RNA interference - a natural regulatory process in the cell to turn off unwanted genes
RNA-Induced Silencing Complex RISC - an enzyme complex in the RNAi pathway which binds siRNA and separates it into guide and passenger strands
shRNA short hairpin RNA formed by  two short complementary sequences of RNA separated by a non-complementary sequence (the hairpin), expressed from a ddRNAi DNA construct
siRNA small interfering RNA - an intermediate in the RNAi pathway; occurs transiently in expressed RNAi from shRNA molecules after Dicer processing and may also be synthesized in a laboratory and introduced to the cell externally
ssRNA single stranded RNA that occurs naturally in RNA viruses or is an intermediate in cellular pathways
sshRNA Synthetic short hairpin RNA molecule -  a shRNA which is synthesized in a laboratory and introduced externally into the target cell
systemic injection Injection into the blood stream for delivery to the whole body or a specific organ or tissue therein
transfection The process of introducing nucleic acids into cells
vectors Molecules (viral and non) used to introduce nucleic acids into cells
zinc finger nucleases ZFNs - artificial restriction enzymes used as reagents to target specific DNA sequences in the cell nucleus. Can only be introduced into cells ex vivo.