The Identification of Host Proteins That Interact with Non-Structural Proteins-1 and-1 of Porcine Reproductive and Respiratory Syndrome Virus-1

Porcine reproductive and respiratory syndrome viruses (PRRSV-1 and -2) are the causative agents of one of the most important infectious diseases affecting the global pig industry. Previous studies, largely focused on PRRSV-2, have shown that non-structural protein-1 alpha (NSP1 alpha) and NSP1 beta modulate host cell responses; however, the underlying molecular mechanisms remain to be fully elucidated. Therefore, we aimed to identify novel PRRSV-1 NSP1-host protein interactions to improve our knowledge of NSP1-mediated immunomodulation. NSP1 alpha and NSP1 beta from a representative western European PRRSV-1 subtype 1 field strain (215-06) were used to screen a cDNA library generated from porcine alveolar macrophages (PAMs), the primary target cell of PRRSV, using the yeast-2-hybrid system. This identified 60 putative binding partners for NSP1 alpha and 115 putative binding partners for NSP1 beta. Of those taken forward for further investigation, 3 interactions with NSP1 alpha and 27 with NSP1 beta were confirmed. These proteins are involved in the immune response, ubiquitination, nuclear transport, or protein expression. Increasing the stringency of the system revealed NSP1 alpha interacts more strongly with PIAS1 than PIAS2, whereas NSP1 beta interacts more weakly with TAB3 and CPSF4. Our study has increased our knowledge of the PRRSV-1 NSP1 alpha and NSP1 beta interactomes, further investigation of which could provide detailed insight into PRRSV immunomodulation and aid vaccine development.