# Rescuing Newcastle disease virus with tag for screening viral-host interacting proteins based on highly efficient reverse genetics

## TL;DR

Researchers developed a system to tag viral proteins in Newcastle disease virus, enabling the study of how these proteins interact with host proteins during infection.

## Contribution

A new reverse genetics system was developed to efficiently rescue tagged Newcastle disease virus for studying viral-host interactions.

## Key findings

- A T7 promoter-based reverse genetics system efficiently rescued tagged Newcastle disease virus regardless of replication ability.
- NDV with HA-tagged structural proteins replicated normally and showed correct subcellular localization.
- HA tag antibodies successfully identified host proteins interacting with the M protein during infection.

## Abstract

The interaction between viral proteins and host proteins plays a crucial role in the process of virus infecting cells. Tags such as HA, His, and Flag do not interfere with the function of fusion proteins and are commonly used to study protein–protein interactions. Adding these tags to viral proteins will address the challenge of the lack of antibodies for screening host proteins that interact with viral proteins during infection. Obtaining viruses with tagged fusion proteins is crucial. This study established a new reverse genetic system with T7 promoter and three plasmids, which efficiently rescued Newcastle disease virus (NDV) regardless of its ability to replicate in cells. Subsequently, using this system, NDV containing a HA-tagged structural protein and NDV carrying a unique tag on each structural protein were successfully rescued. These tagged viruses replicated normally and exhibited genetic stability. Based on tag antibodies, every NDV structural protein was readily detected and showed correct subcellular localization in infected cells. After infecting cells with NDV carrying HA-tagged M protein, several proteins interacting with the M protein during the infection process were screened using HA tag antibodies. The establishment of this system laid the foundation for comprehensive exploration of the interaction between NDV proteins and host proteins.