hnRNP-U enhances the expression of specific genes by stabilizing mRNA

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are thought to be involved in pre-mRNA processing. hnRNP-U, also termed scaffold attachment factor A (SAF-A), binds to pre-mRNA and nuclear matrix/scaffold attachment region DNA elements. However, its role in the regulation of gene expression is as yet poorly understood. In the present study, we show that hnRNP-U specifically enhances the expression of tumor necrosis factor α mRNA by increasing its stability, possibly through binding to the 3′ untranslated region. We also show that hnRNP-U enhances the expression of several other genes as well, including GADD45A, HEXIM1, HOXA2, IER3, NHLH2, and ZFY, by binding to and stabilizing these mRNAs. These results suggest that hnRNP-U enhances the expression of specific genes by regulating mRNA stability.