0000000000202182
AUTHOR
Andreas Bek
Rev protein suppression of complex formation between nuclear proteins and rev-responsive element-containing RNA of human immunodeficiency virus-1
The Rev protein from human immunodeficiency virus type 1 (HIV-1) is known to bind Rev responsive element (RRE) sequence of HIV-1 mRNA. This interaction is thought to enhance expression of viral structural proteins but the mechanism for this effect is uncertain. The aim of this study was to investigate (i) whether other cellular proteins also bind to the RRE sequence and (ii) whether binding of cellular proteins to RRE RNA is influenced by Rev protein. Our results revealed that a variety of RNA-protein complexes are formed when in vitro transcribed RRE-containing RNA is incubated with proteins present in HeLa nuclear extracts. The molecular masses of the most prominent bands in RNase protect…
Inhibition of Formation of Rev-RRE Complex by Pyronin Y
The interaction of pyronin Y, an RNA intercalating drug, with the binding of Rev protein from human immunodeficiency virus type 1 (HIV-1) to Rev-responsive element (RRE)-containing env RNA was studied. In gel retardation assays, recombinant Rev protein tightly bound to in vitro transcribed RRE RNA. Nitrocellulose-filter-binding studies revealed a dissociation constant of ≈(1–2) = 10−10M (Pfeifer et al., 1991). Pyronin Y efficiently suppressed formation of the Rev-RRE complex. At a concentration of 1 μg ml−1, complex formation was almost completely inhibited. Electron microscopy showed that Rev oligomerizes in the presence of RRE-containing RNA with the formation of short rod-like structures…
Purification of a glucose-binding protein from rat liver nuclei. Evidence for a role in targeting of nuclear mRNP to nuclear pore complex.
A nuclear carbohydrate-binding protein with a molecular mass of 67 kDa (CBP67), which is specific for glucose residues, was purified to essential homogeneity from rat liver nuclear extracts. This protein could also be isolated from nuclear ribonucleoprotein (RNP) complexes by extraction in the presence of 0.6 M or 2 M NaCl, but it was absent in polysomal RNP complex. The binding of the purified protein, which has an isoelectric point of 7.3, to glucose-containing glycoconjugates depends on the presence of Ca2+ and Mg2+. Using closed nuclear envelope vesicles as a system to study nuclear transport of RNA, it was shown that both entrapped polysomal mRNA and nuclear RNA precursors are readily …
Association of AUUUA-binding Protein with A + U-rich mRNA during nucleo-cytoplasmic transport
Resealed nuclear envelope (NE) vesicles from rat liver containing entrapped exogenous RNA were used to study the effect of adenosine+uridine binding factor (AUBF), present in cytosolic cell extracts, on ATP-dependent transport of A+U-rich RNA (AU+RNA) and A+U-free RNA (AU-RNA) across the NE. This factor specifically binds to A+U-rich sequences present in the 3' untranslated regions of lymphokine and cytokine mRNAs, containing overlapping AUUUA boxes (granulocyte-macrophage colony stimulating factor, interleukin-3). Addition of AUBF to the extravesicular compartment markedly increased the efflux of the in vitro transcribed, capped and polyadenylated AU+ RNAs. Export of entrapped AU- control …