Genome-Wide Gene Expression Analysis Identifies the Proto-oncogene Tyrosine-Protein Kinase Src as a Crucial Virulence Determinant of Infectious Laryngotracheitis Virus in Chicken Cells

Given the side effects of vaccination against infectious laryngotracheitis (ILT), novel strategies for ILT control and therapy are urgently needed. The modulation of host-virus interactions is a promising strategy to combat the virus; however, the interactions between the host and avian ILT herpesvirus (ILTV) are unclear. Using genome-wide transcriptome studies in combination with a bioinformatic analysis, we identified proto-oncogene tyrosine-protein kinase Src (Src) to be an important modulator of ILTV infection. Src controls the virulence of ILTV and is phosphorylated upon ILTV infection. Functional studies revealed that Src prolongs the survival of host cells by increasing the threshold of virus-induced cell death. Therefore, Src is essential for viral replication in vitro and in ovo but is not required for ILTV-induced cell death. Furthermore, our results identify a positive-feedback loop between Src and the tyrosine kinase focal adhesion kinase (FAK), which is necessary for the phosphorylation of either Src or FAK and is required for Src to modulate ILTV infection. To the best of our knowledge, we are the first to identify a key host regulator controlling host-ILTV interactions. We believe that our findings have revealed a new potential therapeutic target for ILT control and therapy. IMPORTANCE Despite the extensive administration of live attenuated vaccines starting from the mid-20th century and the administration of recombinant vaccines in recent years, infectious laryngotracheitis (ILT) outbreaks due to avian ILT herpesvirus (ILTV) occur worldwide annually. Presently, there are no drugs or control strategies that effectively treat ILT. Targeting of host-virus interactions is considered to be a promising strategy for controlling ILTV infections. However, little is known about the mechanisms governing host-ILTV interactions. The results from our study advance our understanding of host-ILTV interactions on a molecular level and provide experimental evidence that it is possible to control ILT via the manipulation of host-virus interactions.