Nuclear Localization of a Cap-binding Protein Complex (original) (raw)

  1. E. Izaurralde,
  2. C. McGuigan1, and
  3. I.W. Mattaj
  4. Gene Expression Programme, European Molecular Biology Laboratory, 69711 Heidelberg, Germany

Excerpt

Transcripts made by eukaryotic RNA polymerase II are cotranscriptionally modified at their 5′ ends by the addition of a cap structure. This consists of a 7-methyl guanosine residue attached to the first coded nucleotide of the RNA by a 5′-5′ triphosphate linkage (Salditt-Georgieff et al. 1980). The cap has been shown to have a function in several different aspects of RNA metabolism. Early work demonstrated a role in the protection of mRNA from degradation by exo-nucleolytic digestion (Furuichi et al. 1977; Shimotohno et al. 1977). Next it was found that the cap was the binding site for eIF-4F, a heterotrimeric complex of proteins required for the initiation of mRNA translation in the cytoplasm (for review, see Rhoads 1988; Sonenberg 1988). In the nucleus, two functions have been ascribed to the cap structure. It is required for efficient pre-mRNA splicing (Konarska et al. 1984; Krainer et al. 1984; Edery and Sonenberg...