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

Li, Hai; Wang, Fengjie; Han, Zongxi; Gao, Qi; Li, Huixin; Shao, Yuhao; Sun, Nana; Liu, Shengwang

To understand the molecular events induced by ILTV infection in LMH cells when the CPE was evident, RNA was isolated from LMH cells at 2 dpi instead of at 1 dpi. We chose this time because the proportion of virus-infected cells at 1 dpi was too low to differentiate the transcription signature of virus-infected cells from that of all cells ( Fig. 1C and D). We identified 608 genes that were differentially expressed between control and ILTV-infected cells based on the following criteria: (i) a P value of Ͻ0.001 and (ii) a fold change in expression of Ͼ1.5 (data not shown). Hierarchical clustering analysis using these 608 genes demonstrated efficient clustering of biological replicates for control and ILTV-infected cells. We identified 297 downregulated genes and 311 upregulated genes following infection ( Fig. 2A) . For validation, the transcription levels of 20 genes which were randomly selected from the 608 genes were examined using qPCR assays. The qPCR results corresponded with those from the microarray assays (Fig. 2B) .