Post-Transcriptional Control of Class I MHC mRNA Expression in Adenovirus 12-Transformed Cells

Abstract

Expression of the class I transplantation antigens of the major histocompatibility complex (MHC) is suppressed in cells transformed by the oncogenic human adenovirus 12 (Ad12). This suppression of class I antigen expression, which contributes to the tumorigenic phenotype of the transformed cells, has also been observed in some naturally occurring cancers. In the present study, the rate of transcription initiation of class I genes was measured by a nuclear run-on assay in Ad5- and Ad12-transformed cells of three different types. The rate of transcription was the same in all three. The stability of the class I messenger RNA was also examined and found to be the same in all three cell types. The results indicate that in Ad12-transformed cells the suppression is caused by an inhibition of the post-transcriptional processing of class I MHC messenger RNA in the nucleus.

mRNA Instability in the Nucleus Due to a Novel Open Reading Frame Element Is a Major Determinant of the Narrow Tissue Specificity of Folate Receptor α

“…On the other hand, during induction of differentiation in HL60 cells, a decrease in myeloperoxidase expression was associated in part with altered hnRNA levels unrelated to transcription rates but likely due to a failure in RNA processing (31). In many other instances, such as modulation of cellular gene expression by c-myc (22), posttranscriptional regulation in the nucleus is evident but specific mechanisms have not been elucidated; in this and other similar examples (18,20,33,34), the possible levels of gene regulation include hnRNA stability as well as RNA processing. The results of the present study exclude RNA processing as a possible level for the differential regulation of FR-␣ and provide more direct evidence implicating an instability determinant in the FR-␣ mRNA or hnRNA that confers differential stability in the context of cell type.…”

Mycobacteria Exploit p38 Signaling To Affect CD1 Expression and Lipid Antigen Presentation by Human Dendritic Cells

“…The interference of pathogens with the regulation of antigen-presenting molecules is a well-defined escape mechanism that has been studied mainly in relation to MHC-or CD1d-restricted immune responses (20,25,33,35). In contrast, regulation of group 1 CD1 molecules and the pathogen-dependent interference with their membrane expression are poorly understood.…”

General repression of enhanson activity by the adenovirus-2 E1A proteins.

“…Webster et al 1988;Timmers et al 1988Timmers et al , 1989Young et al 1989), but the target within the promoter region of these genes was not identified. The expression of class I major histocompatibility complex (MHC) antigens is also inhibited by the E1A proteins [Friedman and Ricciardi 1988), but in this case, the inhibition may not be only transcriptional (Vaessen et al 1987;Meijer et al 1989).…”