Duplex destabilization by four ribosomal DEAD-box proteins.

DEAD-box proteins are believed to participate in the folding of RNA by destabilizing RNA secondary or tertiary structures. Although these proteins bind and hydrolyze ATP, the mechanism by which nucleotide hydrolysis is coupled to helix destabilization may vary among different DEAD-box proteins. To investigate their abilities to disrupt helices and couple ATP hydrolysis to unwinding, we assayed the Saccharomyces cerevisiae ribosomal DEAD-box proteins, Dbp3p, Dbp4p, Rok1p, and Rrp3p utilizing a series of RNA substrates containing a short duplex and either a 5' or 3' single-stranded region.

The eleven-nineteen lysine-rich leukemia gene (ELL2) influences the histone H3 protein modifications accompanying the shift to secretory immunoglobulin heavy chain mRNA production.

In plasma cells, immunoglobulin heavy chain (IgH) secretory-specific mRNA is made in high abundance as a result of both increased promoter proximal poly(A) site choice and weak splice-site skipping. Ell2, the eleven-nineteen lysine rich leukemia gene, is a transcription elongation factor that is induced ∼6-fold in plasma cells and has been shown to drive secretory-specific mRNA production. Reducing ELL2 by siRNA, which reduced processing to the secretion-specific poly(A) site, also influenced the methylations of histone H3K4 and H3K79 on the IgH gene and impacted positive transcription factor b (pTEFb), Ser-2 carboxyl-terminal phosphorylation, and polyadenylation factor additions to RNA polymerase II.