Gene structures and promoter characteristics of interferon regulatory factor 1 (IRF-1), IRF-2 and IRF-7 from snakehead Channa argus
Three interferon regulatory factor (IRF) genes, CaIRF-1, CaIRF-2 and CaIRF-7, and their promoters of snakehead ( Channa argus) were cloned and characterized. The CaIRF-1 gene consists of ten exons, spans 4.3 kb and encodes a putative peptide of 299 aa. The CaIRF-2 gene consists of nine exons, spans...
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Veröffentlicht in: | Molecular immunology 2008-04, Vol.45 (8), p.2419-2428 |
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Sprache: | eng |
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Zusammenfassung: | Three interferon regulatory factor (IRF) genes,
CaIRF-1,
CaIRF-2 and
CaIRF-7, and their promoters of snakehead (
Channa argus) were cloned and characterized. The
CaIRF-1 gene consists of ten exons, spans 4.3
kb and encodes a putative peptide of 299 aa. The
CaIRF-2 gene consists of nine exons, spans 8
kb and encodes a putative peptide of 328 aa. The gene organizations of
CaIRF-1 and
CaIRF-2 are very similar to that of human
IRF-1 and
IRF-2 except more compact. Comparison of exon–intron organization of the two genes indicated a common evolutionary structure, notably within the exons encoding the DNA binding domain (DBD) of the two factors. The
CaIRF-7 gene spans 4.1
kb and encodes a putative peptide of 437 aa. However, the gene organization of
CaIRF-7 consisting of ten exons is different to human IRF-7a gene which has an intron in 5′ UTR. Three CaIRFs share homology in N-terminal encompassing the DBD that contains a characteristic repeat of tryptophan residues. The promoters of
CaIRF-1 and
CaIRF-2 genes contain the conserved sites for NF-κB and Sp1. The γ-IFN activation sites (GAS) were found in the promoters of
CaIRF-1 and
CaIRF-7. The promoter of
CaIRF-7 contains conserved interferon stimulating response element (ISRE) which is characteristic of IFN-induced gene promoter, and suggests that there also exist intracellular amplifier circuit in fish IFN signal pathway. Moreover, the element GAAANN oriented in both directions is repeated in
CaIRF promoter regions, which confers to further inducibility by IFN. The constitutive expression of
CaIRF genes were found to increase obviously in response to induction by the known IFN-inducer poly I:C. |
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ISSN: | 0161-5890 1872-9142 |
DOI: | 10.1016/j.molimm.2007.11.011 |