The HLA class II expression is controlled by the transcriptional activator @entity4637 . The transcription of @entity4637 is controlled by different promoters, among which promoter-IV is inducible by @entity379 . We analysed the regulation of HLA class II molecules by @entity379 in a large series of @entity1 @entity521 cell lines. No induction of surface or intracellular HLA class II molecules and of specific mRNA was observed, in all @entity521 , with the exception of a nonprototypic cell line, @entity8605 . In a large @entity521 @entity379 induced expression of @entity4637 mRNA, derived from promoter-IV, which was not methylated. In contrast, in another @entity521 , @entity4637 was not inducible by @entity379 and @entity4637 promoter-IV was either completely or partially methylated. Interestingly, the use of DNA demethylating agents restored @entity4637 gene transcriptional activation by @entity379 , but not HLA class II expression. The defect of HLA class II was not related to alterations in @entity18622 or NF-Y transcription factors, as suggested by EMSA or @entity18622 gene transfection experiments. In addition, the transfection of a functional @entity4637 cDNA failed to induce HLA class II expression in typical @entity521 cells. Confocal microscopy and Western blot analysis suggested a defective nuclear translocation and/or reduced protein synthesis in @entity4637 -transfected NB cells. Altogether, these data point to multiple mechanisms preventing HLA class II expression in the @entity521 , either involving @entity4637 promoter-IV silencing, or acting at the @entity4637 post-transcriptional level.

Different levels of control prevent interferon-gamma-inducible HLA-class II expression in @entity1 XXXX cells.

@entity1 :: ('9606', 'Species') :: ['human'] @entity4637 :: ('4261', 'Gene') :: ['CIITA'] @entity379 :: ('3458', 'Gene') :: ['IFN-gamma'] @entity8605 :: ('MESH:D016518', 'Disease') :: ['ACN'] @entity521 :: ('MESH:D009447', 'Disease') :: ['neuroblastomas', 'neuroblastoma', 'subset of neuroblastomas'] @entity18622 :: ('5989', 'Gene') :: ['RFX']
@entity521 :: (MESH:D009447,Disease) :: ['neuroblastoma']
