RNA virus replicase "free rides" in and out of the nucleus to initiate replication

RNA virus replicase "free rides" in and out of the nucleus to initiate replication

RNA virus replicase "free rides" into and out of the nucleus to initiate replication RNA virus replicase "free rides" into and out of the nucleus to initiate replication

The mechanism by which RNA virus replicase is transported from the nucleus to the cytoplasm and initiates virus replication.
Photo courtesy of the Institute of Plant Protection, Chinese Academy of Agricultural Sciences

 The mechanism of RNA virus replicase transporting from the nucleus to the cytoplasm and initiating virus replication Photo courtesy of the Institute of Plant Protection, Chinese Academy of Agricultural Sciences

Recently, " New Phytologist " published online the latest research results of the Crop Pest Functional Genomics Research Innovation Team of the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences
.

The results found that the nuclear export protein XPO1 in plants can transport the hematoxylated virus replicase NIb from the nucleus to the cytoplasmic vesicles, thereby initiating virus replication and promoting virus infection

New Phytologist

Potato Yviridae virus is the largest variety of plant RNA viruses, causing serious economic losses on food crops, cash crops, fruit trees and vegetables worldwide such as potatoes, soybeans, rapeseed, peaches and cabbage
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Turnip mosaic virus (TuMV) is a representative species of this family virus, which mainly infects cruciferous vegetables

After the turnip mosaic virus invades the host cell, in order to carry out the virus replication process, a variety of host factors must be used
.

The key step is that the turnip mosaic virus replicase NIb protein passes through the nuclear pore on the nuclear membrane, enters the nucleus for some modification and transformation, and then enters the vesicles in the cytoplasm from the nucleus to initiate the replication process

In order to clarify which host factors are involved in these processes, the team used the turnip mosaic virus NIb as a bait to screen the nuclear export protein XPO1 of Nicotiana benthamiana and Arabidopsis thaliana, which can directly bind to the turnip mosaic virus replicase NIb protein
.

The nuclear export protein XPO1 is a transport function protein that exists in the nuclear pore and is responsible for the transfer of materials inside and outside the nucleus.
It is equivalent to a "transporter"
.

Studies have found that the nuclear export protein XPO1 not only undertakes the normal transfer of materials inside and outside the nucleus of plant cells, but also “free rides” by the invading RNA virus to transport virus replicase

They found that the N-terminal of nuclear export protein XPO1 is the nuclear import domain Importin-beta, and the C-terminal is the nuclear export domain CRM1, which are responsible for the nuclear import and nuclear export of the NIb protein of the turnip mosaic virus replicase respectively
.

Hematoxylation modification is a key molecular switch for nuclear export protein XPO1 to mediate the export of turnip mosaic virus replicase NIb protein to the nucleus.

In addition, the nuclear export protein XPO1 also plays an important role in the plant defense response induced by NPR1, a key gene regulating plant disease resistance
.

Mutation of XPO1 can prevent the replication of a variety of plant RNA viruses, allowing plants to obtain broad-spectrum antiviral properties

This study clarified the mechanism by which the nuclear export protein XPO1 mediates the transport of RNA virus replicase from the nucleus to the cytoplasm to initiate virus replication, and provides a target for the broad-spectrum disease resistance of plants
.

The research was funded by the National Natural Science Foundation of China
.

(Source: China Science News Li Chen)

Related paper information: https://doi.

https://doi.
org/10.
1111/NPH.
17657