Biology Reference
In-Depth Information
Caveolae-mediated endocytosis
Caveosome
Smooth ER
Virus infection pathway
Virus production and secretion pathway
SV40 particle
VP1-pentamer-VP2 or VP3
complex
minichromosome
Golgi
Fig. 4.
Schematic representation of SV40 virus infection and secretion
pathway.
Upper figure.
1. SV40 virus first binds to the cell surface. 2. SV40
virus is endocytosed in caveolin 1 containing vesicles and delivered to caveo-
somes. 3. SV40 virus leaves for smooth endoplasmic reticulum. 4. SV40 viral
proteins and host proteins may transport virus genome called minichro-
mosme into nucleus.
Lower figure,
1. SV40 VP1-pentamer binds to one minor
capsid protein VP2 or VP3 in cytoplasm. 2. VP1-pentamer-VP2 or -VP3
complex transport into nucleus. 3. VP1-pentamer-VP2 or -VP3 complex
select virus genome called minichromosome from the replicating and tran-
scribing pools to be encapsidated. 4. Complete SV40 virion escapes from
host cell with or without cell lysis.
VP3 in the nucleus is predetermined by formation of the complex in
the cytoplasm. After formation of the VP1-pentamer-VP2 or -VP3
complex, the latter enters into the nucleus to enclose viral genome
that complex with histone, termed minichromosome for the SV40
capsid assembly. From the isolated SV40 minichromosome structural
analysis, it has been shown that minichromosome contains all five his-
tones, including histone HI that exists in solution under approxi-
mately physiological ionic conditions as a compact roughly spherical
particle approximately 300 Å in diameter in nucleus.
13
The
in vitro
