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- Överby, Anna K, et al.
(författare)
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The cytoplasmic tails of Uukuniemi Virus (Bunyaviridae) G(N) and G(C) glycoproteins are important for intracellular targeting and the budding of virus-like particles
- 2007
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 81:20, s. 11381-11391
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Tidskriftsartikel (refereegranskat)abstract
- Functional motifs within the cytoplasmic tails of the two glycoproteins G(N) and G(C) of Uukuniemi virus (UUK) (Bunyaviridae family) were identified with the help of our recently developed virus-like particle (VLP) system for UUK virus (A. K. Overby, V. Popov, E. P. Neve, and R. F. Pettersson, J. Virol. 80:10428-10435, 2006). We previously reported that information necessary for the packaging of ribonucleoproteins into VLPs is located within the G(N) cytoplasmic tail (A. K. Overby, R. F. Pettersson, and E. P. Neve, J. Virol. 81:3198-3205, 2007). The G(N) glycoprotein cytoplasmic tail specifically interacts with the ribonucleoproteins and is critical for genome packaging. In addition, two other regions in the G(N) cytoplasmic tail, encompassing residues 21 to 25 and 46 to 50, were shown to be important for particle generation and release. By the introduction of point mutations within these two regions, we demonstrate that leucines at positions 23 and 24 are crucial for the initiation of VLP budding, while leucine 46, glutamate 47, and leucine 50 are important for efficient exit from the endoplasmic reticulum and subsequent transport to the Golgi complex. We found that budding and particle generation are highly dependent on the intracellular localization of both glycoproteins. The short cytoplasmic tail of UUK G(C) contains a lysine at position -3 from the C terminus that is highly conserved among members of the Phlebovirus, Hantavirus, and Orthobunyavirus genera. Mutating this single amino acid residue in G(C) resulted in the mislocalization of not only G(C) but also G(N) to the plasma membrane, and VLP generation was compromised in cells expressing this mutant. Together, these results demonstrate that the cytoplasmic tails of both G(N) and G(C) contain specific information necessary for efficient virus particle generation.
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| 2. |
- Överby, Anna K, et al.
(författare)
-
The glycoprotein cytoplasmic tail of Uukuniemi virus (Bunyaviridae) interacts with ribonucleoproteins and is critical for genome packaging
- 2007
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 81:7, s. 3198-3205
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed the importance of specific amino acids in the cytoplasmic tail of the glycoprotein G(N) for packaging of ribonucleoproteins (RNPs) into virus-like particles (VLPs) of Uukuniemi virus (UUK virus), a member of the Bunyaviridae family. In order to study packaging, we added the G(N)/G(C) glycoprotein precursor (p110) to a polymerase I-driven minigenome rescue system to generate VLPs that are released into the supernatant. These particles can infect new cells, and reporter gene expression can be detected. To determine the role of UUK virus glycoproteins in RNP packaging, we performed an alanine scan of the glycoprotein G(N) cytoplasmic tail (amino acids 1 to 81). First, we discovered three regions in the tail (amino acids 21 to 25, 46 to 50, and 71 to 81) which are important for minigenome transfer by VLPs. Further mutational analysis identified four amino acids that were important for RNP packaging. These amino acids are essential for the binding of nucleoproteins and RNPs to the glycoprotein without affecting the morphology of the particles. No segment-specific interactions between the RNA and the cytoplasmic tail could be observed. We propose that VLP systems are useful tools for analyzing protein-protein interactions important for packaging of viral genome segments, assembly, and budding of other members of the Bunyaviridae family.
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