Table of Contents
What is the diameter of a virion?
Virion properties Typically, virions are 19×50 nm, but range between 18 and 20 nm in width and 48 and 53 nm in length (Figure 1). Optical diffraction patterns of the virions resemble those of virions of Alfalfa mosaic virus, suggesting a morphological subunit diameter of about 10 nm and a T=1 icosahedral symmetry.
Does reovirus have double-stranded RNA?
Rotaviruses are double stranded RNA viruses comprising a genus within the family Reoviridae. The mature virus particles are triple layered, approximately 70 nm in diameter, and possess icosahedral symmetry.
What is the size of the smallest virus?
AAV is the smallest DNA virus with an average size of 20 nm. AAV was discovered in 1965 as a defective contaminating virus in an adenovirus stock (Atchison et al., 1965).
How many dsRNA segments are present in the reovirus genome?
Reovirus particles can contain 9, 10, 11 or 12 segments of linear dsRNA, depending on the genus. The individual Mr of these RNA molecules ranges from 0.2 to 3.0×106.
Which virus has the largest RNA genome?
Coronaviruses are single-stranded, positive-sense RNA viruses and have the largest genomes known [around 30 kilobases (kb); refs. 1 and 2] among RNA viruses.
What is unique about reovirus?
dsRNA Viruses Reoviruses are nonenveloped and particles consist of two or three concentric icosahedral capsid layers. The genome segments are found within the innermost, T=1 icosahedral shell. A unique feature of the reovirus replication cycle is that the genome segments are transcribed from within the capsid.
What is the smallest bacterial genome size?
1.3 Mb
Bacteria and Archaea. The smallest known genome of a free-living bacterium is 1.3 Mb with ~1100 genes. However, significantly more reduced genomes are commonly observed in naturally occurring symbiotic and parasitic organisms.
What is the structure of a reovirus?
Structure of the reovirus virion. Reoviruses are non-enveloped and have an icosahedral capsid composed of an outer (T=13) and inner (T=2) protein shell. The genomes of viruses in Reoviridae contain 10–12 segments which are grouped into three categories corresponding to their size: L (large), M (medium) and S (small).
What is a Reoviridae protein?
Reoviridae proteins are denoted by the Greek character corresponding to the segment it was translated from (the L segment encodes for λ proteins, the M segment encodes for μ proteins and the S segment encodes for σ proteins).
How many proteins are in a virus genome?
The genomes of viruses in Reoviridae contain 10–12 segments which are grouped into three categories corresponding to their size: L (large), M (medium) and S (small). Segments range from about 0.2 to 3 kbp and each segment encodes 1–3 proteins (10-14 proteins in total).
How many nucleotides are in reovirus S4 cDNA?
A full-length cDNA copy of reovirus double-stranded RNA genome segment S4 which codes for a major virion structural polypeptide, sigma 3, has been completely sequenced. The 1,196-nucleotide cDNA contains a single long open reading frame in the plus strand extending 1,095 nucleotides from the 5′-proximal A-T-G to a single stop codon.