In
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
, the coronavirus
frameshifting
A frameshift mutation (also called a framing error or a reading frame shift) is a genetic mutation caused by indels ( insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three. Due to the triplet nature ...
stimulation element is a
conserved stem-loop
Stem-loop intramolecular base pairing is a pattern that can occur in single-stranded RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when ...
of
RNA
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
found in
coronavirus
Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the com ...
es that can promote
ribosomal frameshifting
Ribosomal frameshifting, also known as translational frameshifting or translational recoding, is a biological phenomenon that occurs during translation that results in the production of multiple, unique proteins from a single mRNA. The process can ...
. Such RNA molecules interact with a
downstream region to form a
pseudoknot
__NOTOC__
A pseudoknot is a nucleic acid secondary structure containing at least two stem-loop structures in which half of one stem is intercalated between the two halves of another stem. The pseudoknot was first recognized in the turnip yellow ...
structure; the region varies according to the virus but pseudoknot formation is known to stimulate
frameshifting
A frameshift mutation (also called a framing error or a reading frame shift) is a genetic mutation caused by indels ( insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three. Due to the triplet nature ...
. In the classical situation, a sequence 32
nucleotide
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...
s downstream of the stem is complementary to part of the loop. In other coronaviruses, however, another stem-loop structure around 150 nucleotides downstream can interact with members of this family to form
kissing stem-loop
In genetics, a kissing stem-loop, or kissing stem loop interaction, is formed in ribonucleic acid (RNA) when two bases between two hairpin loops pair. These intra- and intermolecular kissing interactions are important in forming the tertiary or q ...
s and stimulate frameshifting.
Other RNA families identified in the coronavirus include the
coronavirus 3′ stem-loop II-like motif (s2m), the
coronavirus packaging signal and the
coronavirus 3′ UTR pseudoknot.
During protein synthesis, rapidly changing conditions in the cell can cause
ribosomal pausing. In coronaviruses, this can affect growth rate and trigger translational abandonment. This releases the ribosome from the mRNA and the incomplete polypeptide is targeted for destruction.
See also
*
Translational frameshift
Ribosomal frameshifting, also known as translational frameshifting or translational recoding, is a biological phenomenon that occurs during translation that results in the production of multiple, unique proteins from a single mRNA. The process can ...
*
Slippery sequence
A slippery sequence is a small section of codon nucleotide sequences (usually UUUAAAC) that controls the rate and chance of ribosomal frameshifting. A slippery sequence causes a faster ribosomal transfer which in turn can cause the reading ribosome ...
*
Coronavirus 5′ UTR
*
Coronavirus 3′ UTR
*
Coronavirus 3′ UTR pseudoknot
*
Coronavirus 3′ stem-loop II-like motif (s2m)
*
Coronavirus packaging signal
References
External links
*
Cis-regulatory RNA elements
Coronaviridae
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