Functional Genomics Analysis of the Virus-Host Interaction in FV3-Infected Xenopus laevis

Yun Tian, Tennessee State University


This dissertation was designed to provide better understanding on the amphibian interferon (IFN) complex and relevant antiviral regulation in a Xenopus model infected by a Frog Virus 3 (FV3). Four objectives were performed: (1) Determine differential expression of amphibian IFN genes and IFN-stimulated genes (ISGs) induced by FV3 infection in Xenopus laevis kidney cell line (A6); (2) Functionally evaluate antiviral activity of representative IFN peptides against FV3 infection; (3) Clone some IFN receptor genes into expression vectors for future functional analysis; and (4) Examine ranaviral antagonism against host IFN signaling using functional prediction and virus-targeting transcriptomic validation. Three groups of IFN genes (IFNX3, IFNX4 and IFNX6) and two ISG genes (IL11 and TNFAIP3) were significantly up-regulated post FV3 infection in A6 cells. Four type I IFN peptides (encoded by three intron-containing IFN genes of IFN4, IFN6, and IFN7, as well as one intronless IFNX4 gene) and one type III IFN peptide (encoded by the intron-containing gene of IFNL4), showed antiviral activity against FV3. Five expression constructs to express three isoforms of X. laevis IFN-α/β receptor subunit 1 (IFNAR1) and two isoforms of IFNAR subunit 2 (IFNAR2) were cloned in an episomal mammalian expression vector. A virus-targeting transcriptome analysis using several frog tissues infected by FV3 in vivo were performed. Several newly identified ranaviral mimicking-proteins, which are very likely to functionally interfere with host IFN response, were predicted. The viral microRNAs involved in IFN-mediated responses were detected. This indicates that ranaviruses have evolved diverse mechanisms to regulate the virus-host interaction.

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Recommended Citation

Yun Tian, "Functional Genomics Analysis of the Virus-Host Interaction in FV3-Infected Xenopus laevis" (2022). ETD Collection for Tennessee State University. Paper AAI29059828.