The mRNA cap structure stimulates rate of poly(A) removal and amplifies processivity of degradation
2001 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 276, no 30, 27923-27929 p.Article in journal (Refereed) Published
Poly(A)-specific ribonuclease (PARN) is an oligomeric, processive, and cap-interacting 3' exonuclease. We have studied how the m7G(5')ppp(5')G cap structure affects the activity of PARN. It is shown that the cap has four distinct effects: (i) It stimulates the rate of deadenylation if provided in cis; (ii) it inhibits deadenylation if provided at high concentration in trans; (iii) it stimulates deadenylation if provided at low concentration in trans; and (iv) it increases the processivity of PARN when provided in cis. It is shown that the catalytic and cap binding sites on PARN are separate. The important roles of the 7-methyl group and the inverted guanosine residue of the cap are demonstrated. An active deadenylation complex, consisting of the poly(A)-tailed RNA substrate and PARN, has been identified. Complex formation does not require a cap structure on the RNA substrate. The multiple effects of cap are all accounted for by a simple, kinetic model that takes the processivity of PARN into account.
Place, publisher, year, edition, pages
2001. Vol. 276, no 30, 27923-27929 p.
mammalian messenger-rna, saccharomyces-cerevisiae, in-vitro, poly(a)-binding protein, translation initiation, binding-protein, poly(a)-specific ribonuclease, crystal-structure, dna-replication, xenopus oocytes
IdentifiersURN: urn:nbn:se:uu:diva-38285DOI: 10.1074/jbc.M102270200ISI: 000170093400025PubMedID: 11359775OAI: oai:DiVA.org:uu-38285DiVA: diva2:66184