Biology Reference
In-Depth Information
Fig. 5.
Formation of nucleocapsid-like structures. Coexpression of NP,
VP35, and VP24 is necessary and sufficient for the formation of nucleocap-
sid-like structures. (Courtesy of Huang
et al
., 2002.)
nucleocapsids, while VP24 may play a transient catalytic role during nucle-
ocapsid formation or serve as molecular glue between NP and VP35.
Electron microscopic studies have also revealed nucleocapsid
aggregation in the cytoplasm at an appreciable distance from the cell
surface.
48
Once the newly synthesized genomic RNA is encapsidated in
the cytoplasm, the mature nucleocapsids must be transported to the
plasma membrane for virus budding. As discussed above, the VP40
protein may be involved in this step. This assumption is supported
by the findings that NP and VP40 colocalize in cells expressing both
proteins, and that NP expression increases the efficiency of VP40-
VLP particle release.
50,51
Moreover, VP40 interacts with VP35.
10
In
filovirus-infected cells, however, direct interactions between nucleocap-
sids and VP40 have not been demonstrated. GP may also be involved
in this transport process since its cytoplasmic tail interacts with VP40.
Conclusion
Although the detailed mechanisms of filovirus genesis are still unknown,
much has been learned about the individual steps of the assembly and
