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The UL144 gene product of human cytomegalovirus activates NFκB via a TRAF6‐dependent mechanism
Author(s) -
Poole Emma,
King Christine A,
Sinclair John H,
Alcami Antonio
Publication year - 2006
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7601287
Subject(s) - biology , mechanism (biology) , human cytomegalovirus , nf κb , gene , virology , cytomegalovirus , gene product , nfkb1 , product (mathematics) , microbiology and biotechnology , signal transduction , genetics , gene expression , virus , herpesviridae , viral disease , transcription factor , philosophy , geometry , mathematics , epistemology
Molecular mimicry of cytokines and cytokine receptors is a strategy used by poxviruses and herpesviruses to modulate host immunity. The human cytomegalovirus (HCMV) UL144 gene, situated in the UL/b′ region of the viral genome, has amino‐acid sequence similarity to members of the tumour necrosis factor receptor superfamily. We report that UL144 is a potent activator of NFκB‐induced transcription in a TRAF6‐dependent manner. This NFκB activation enhances expression of the chemokine CCL22 through the NFκB responsive elements found in its promoter. In contrast to the clinical HCMV isolates, extensively passaged laboratory strains lack the UL/b′ region and hence do not encode UL144. Consistent with this, infection with viruses that carry UL/b′ causes NFκB activation and CCL22 expression, a phenotype that is not observed after infections with strains lacking the UL/b′ region. Moreover, knockdown of UL144, TRAF6 or NFκB by specific siRNA in infections with UL144‐encoding HCMV prevents the activation of CCL22 expression normally observed after infection with UL/b′ positive HCMV. Upregulation of CCL22, which attracts Th2 and regulatory T cells, may help HCMV evade immune surveillance.