Virus Taxonomy
Order: Unassigned
Family: Bunyaviridae
Genus: Phlebovirus
Species: Toscana virus
talk.ictvonline.org Structure and genome
The toscana virus (TOSV) is a negative-single stranded RNA virus, it is spherical in shape, it
has an enveloped surrounding its capsid, and it has a diameter of 80–120 nm. Its genome is
partitioned into three segments, termed (large)L, (medium)M and (small)S. With L about 6,400
nucleotides in length, M about 4,200 nucleotides in length, and S about 1,900 nucleotides in
length. L encodes for the viral polymerase, M encodes for structural glycoproteins and S encodes
for nucleoproteins (kuhn,Bebermeyer & Hartmann-Klosterkotter , 2005).
Pathogenesis
Just like Naples virus, …show more content…
Penetration
Penetration is enhanced by caveolin mediated endocytosis, which leads to the formation of an
endosome with low endosomal pH, later in the late endosome the low pH leads to the induction
of endosomal membrane fusion with Gc protein of the viral envelope which results in the
preparation for uncoating of the viral genome to occur
Uncoating
The fusion of the virus and endosomal membrane allow release of the viral ribonucleoprotein
complexes into the cytoplasm where the virus transcription and replication occurs
Replication
Immediately after uncoating in the cytoplasm, RNA dependent RNA polymerase (RdRp)
brought in with the viral genome starts transcribing the viral mRNA from the negative sense
viral RNA fragments. During initiation, RdRp employs an endonuclease activity to cleave and
“snatch” the cap of host cell mRNA to prime viral transcription, the transcribed viral mRNA is
later translated into structural and non structural viral proteins by the host ribosomes, after
translation is completed, RdRp transcribes a positive strand RNA from the initial viral
Order: Unassigned
Family: Bunyaviridae
Genus: Phlebovirus
Species: Toscana virus
talk.ictvonline.org Structure and genome
The toscana virus (TOSV) is a negative-single stranded RNA virus, it is spherical in shape, it
has an enveloped surrounding its capsid, and it has a diameter of 80–120 nm. Its genome is
partitioned into three segments, termed (large)L, (medium)M and (small)S. With L about 6,400
nucleotides in length, M about 4,200 nucleotides in length, and S about 1,900 nucleotides in
length. L encodes for the viral polymerase, M encodes for structural glycoproteins and S encodes
for nucleoproteins (kuhn,Bebermeyer & Hartmann-Klosterkotter , 2005).
Pathogenesis
Just like Naples virus, …show more content…
Penetration
Penetration is enhanced by caveolin mediated endocytosis, which leads to the formation of an
endosome with low endosomal pH, later in the late endosome the low pH leads to the induction
of endosomal membrane fusion with Gc protein of the viral envelope which results in the
preparation for uncoating of the viral genome to occur
Uncoating
The fusion of the virus and endosomal membrane allow release of the viral ribonucleoprotein
complexes into the cytoplasm where the virus transcription and replication occurs
Replication
Immediately after uncoating in the cytoplasm, RNA dependent RNA polymerase (RdRp)
brought in with the viral genome starts transcribing the viral mRNA from the negative sense
viral RNA fragments. During initiation, RdRp employs an endonuclease activity to cleave and
“snatch” the cap of host cell mRNA to prime viral transcription, the transcribed viral mRNA is
later translated into structural and non structural viral proteins by the host ribosomes, after
translation is completed, RdRp transcribes a positive strand RNA from the initial viral