What we’re talking about

February 26, 2009

A recent paper from James Manley’s lab details a proteomic analysis of the polyadenylation complex.

In this study, the polyadenylation complex was purified using an affinity technique, attaching a functional polyadenylation signal to a series of MS2 coat protein binding sites (of course, all within the context of an RNA), incubating this RNA with Hela cell extracts, and purifying the RNA using a maltose binding protein-MS2 coat protein fusion. The protein components of the complex were characterized using the so-called Multidimensional Protein Identification Technology (MudPIT). In addition to the usual players* (CPSF, CstF, CFIm) were found proteins suggestive of links with transcription, splicing, and DNA repair. Curiously, the sole poly(A) polymerase found was not the canonical enzyme but an isoform first identified as an enzyme that adenylates the RNA present in the so-called Signal Recognition Particle (SRP). Moreover, readily detectable was a testis-specific CstF64 variant (CstF64-tau) as well as the canonical 64 kD subunit of CstF. CFIIm was largely absent. Read the rest of this entry »