The evolutionarily conserved subunits Rrp4 and Csl4 confer different substrate specificities to the archaeal exosome.
We studied the substrate specificity of the exosome of Sulfolobus solfataricus using the catalytically active Rrp41-Rrp42-hexamer and complexes containing the RNA-binding subunits Rrp4 or Csl4. The conservation of both Rrp4 and Csl4 in archaeal and eukaryotic exosomes suggests specific functions for each of them. We found that they confer different specificities to the exosome: RNA with an A-poor 3'-end is degraded with higher efficiency by the Csl4-exosome, while the Rrp4-exosome strongly prefers poly(A)-RNA. High C-content and polyuridylation negatively influence RNA processing by all complexes, and, in contrast to the hexamer, the Rrp4-exosome prefers longer substrates.
Roppelt
Verena
V
Institut für Mikrobiologie und Molekularbiologie der JLU Giessen, Giessen, Germany.
Klug
Gabriele
G
Evguenieva-Hackenberg
Elena
E
D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D055354:Exosomes / Q000378:metabolism*; D008969:Molecular Sequence Data; D019642:RNA, Archaeal / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D048229:Sulfolobus solfataricus / Q000378:metabolism
D019843:Archaeal Proteins; D019642:RNA, Archaeal