Characteristics of the interferon regulatory factor pairs zfIRF5/7 and their stimulation expression by ISKNV Infection in zebrafish (Danio rerio).
The interferon regulatory factor (IRF) family plays critical roles in a host's virus infection responses. In this study, two IRF family members, zfIRF5 and zfIRF7, are identified in zebrafish. The zfIRF5 protein encodes 297 amino acids without the carboxyl IRF3 domain. We suggest that zfIRF5 is a new kind of splicing variant, following the nine other kinds of IRF5 splicing variants found in mammals. The zfIRF7 protein is identified as a member of the IRF7 family, compared to the human IRF7 protein, the amino acid sequence of zfIRF7 only with 29% identity and devoid a virus activated domain (VAD). There zfIRF5/7 proteins are expressed in all 11 selective zebrafish tissues within 6-120h of embryonic development. Laser confocal microscopy shows that the full length the proteins are separately located in the cytoplasm. Mutation experiments show that the nuclear localization signals (NLS) of zfIRF7 and zfIRF-5 are at the N-terminal and C-terminals, respectively. In the assays, zfIRF7 expression increases during infectious spleen and kidney necrosis virus (ISKNV) infection and by poly(I:C) and LPS injections, both of which activate the transcriptional activity of L8G5-luc plasmids. The over-expression of zfIRF5/7 activates the interferon-stimulated response elements (ISRE) signal pathway. In addition, zfIRF7 can activate IFN-β, zfIRF5/7. Co-immunoprecipitation assays and laser co-confocal microscopy show that the two proteins could interact, and zfIRF7 may stimulate zfIRF5 to move into the nucleus. The co-expression of zfIRF5/IRF7 suppresses the transcriptional activities of IFN-β in HEK293T cells.
Xiang
Zhiming
Z
State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China.
Dong
Chuanfu
C
Qi
Lin
L
Chen
Weijian
W
Huang
Lichao
L
Li
Zhongsheng
Z
Xia
Qiong
Q
Liu
Dong
D
Huang
Mengli
M
Weng
Shaoping
S
He
Jianguo
J
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004266:DNA Virus Infections / Q000276:immunology* / Q000378:metabolism; D015870:Gene Expression; D017930:Genes, Reporter; D050835:Interferon Regulatory Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007497:Iridoviridae; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
C555117:IRF5 protein, zebrafish; C555118:IRF7 protein, zebrafish; D050835:Interferon Regulatory Factors; D015534:Trans-Activators; D029961:Zebrafish Proteins