Transcriptional Profiling of Host Gene Expression in Chicken Embryo Fibroblasts Infected with Reticuloendotheliosis Virus Strain HA1101

Abstract

Reticuloendotheliosis virus (REV), a member of the Gammaretrovirus genus in the Retroviridae family, causes an immunosuppressive, oncogenic and runting-stunting syndrome in multiple avian hosts. To better understand the host interactions at the transcriptional level, microarray data analysis was performed in chicken embryo fibroblast cells at 1, 3, 5, and 7 days after infection with REV. This study identified 1,785 differentially expressed genes that were classified into several functional groups including signal transduction, immune response, biological adhesion and endocytosis. Significant differences were mainly observed in the expression of genes involved in the immune response, especially during the later post-infection time points. These results revealed that differentially expressed genes IL6, STAT1, MyD88, TLRs, NF-κB, IRF-7, and ISGs play important roles in the pathogenicity of REV infection. Our study is the first to use microarray analysis to investigate REV, and these findings provide insights into the underlying mechanisms of the host antiviral response and the molecular basis of viral pathogenesis.

Fig 1. REV infection in chicken embryo fibroblasts.

Detection of REV group antigen in infected monolayer of CEFs was visualised by IFA on day 1 (A), day 2 (B), day 3 (C), day 4 (D), day 5 (E), day 6 (F), day 7 (G) and day 10 (H) using fluorescence microscopy at an original magnification of 400×.

Fig 2. Venn diagram of significantly differentially expressed transcripts over the time course of REV infection.

The image displays the number and overlap of differentially expressed transcripts in response to in vitro REV infection at 1, 3, 5, and 7 days post-infection. The numbers of transcripts differentially expressed at more than one time point are shown in the overlapping regions. Additionally, the intersection of the four circles indicates transcripts that were up- or down-regulated at all time points of REV infection.

Fig 3. Hierarchical clustering (A) and k-means clustering (B) of differentially expressed transcripts of REV infected CEFs at different post-infection time points.

Expression profiles of differentially expressed transcripts with p < 0.05 at all time points and fold changes > +/- 2 at one or more time points. These significantly regulated transcripts were clustered into 9 distinct groups having similar expression response profiles over the time course of REV infection.

Fig 4. Gene ontology analysis of differentially expressed genes according to their biological process (A), cellular function (B), and molecular function (C).

Each colour represents a different GO term, and the number of enriched target genes are shown after the name of the GO term. Only the top ten GO terms in each category are listed here. The complete GO analysis dataset is shown in S3 Table.