engleski

RESISTANCE OF RAE-1 DELTA TO DOWN-REGULATION BY MOUSE CYTOMEGALOVIRUS

NKG2D is a dominant activating NK cell receptor also expressed by activated CD8+ T cells and subsets of gamma/delta T cells. Several mouse NKG2D ligands can be distinguished: murine UL16-binding protein like transcript (MULT-1), the minor histocompatibility antigen H60 and the retinoic acid early inducible (RAE)-1 isoforms ; RAE-1alpha, beta, gamma, delta and epsilon. Recently, we have shown that mouse cytomegalovirus (MCMV) down-regulates all NKG2D ligands on cells derived from BALB/c mice. Product of MCMV m145 gene interferes with the expression of MULT-1, m155 gene product down-regulates H60 and m152-encoded gp40 negatively regulates RAE-1alpha, beta and gamma. Here we show that one of the RAE-1 isoforms, RAE-1delta, is resistant to down-regulation by MCMV. Using VectorNT AlignX program we have analyzed the sequence differences between RAE-1 isoforms and defined particular sequence present in RAE-1alpha, beta and gamma, but absent in RAE-1delta. We have constructed mutated RAE-1gamma gene lacking these amino acids to test whether this can explain the resistance of RAE-1delta to m152/gp40. The gene for RAE-1gamma as well as its mutated form was cloned in the pB45-Neo vector and transfected into NIH3T3 cells. Produced transfectant cell lines were infected with MCMV and our results showed that mutated RAE-1gamma became resistant to m152/gp40-mediated down-regulation. Altogether, in contrast with previous assumption that MCMV down-regulates all NKG2D ligands, our results show that RAE-1delta is an exception.

Murine cytomegalovirus; NK cells; NKG2D; RAE-1

nije evidentirano