Previous Article | Next Article ![]()
Molecular and Cellular Biology, December 2001, p. 8045-8055, Vol. 21, No. 23
Department of Molecular Biology and
Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts
University, Boston, Massachusetts 02111
Received 30 May 2001/Returned for modification 22 June
2001/Accepted 28 August 2001
In Saccharomyces cerevisiae, four factors [cleavage
factor I (CF I), CF II, polyadenylation factor I (PF I), and poly(A)
polymerase (PAP)] are required for maturation of the 3' end of the
mRNA. CF I and CF II are required for cleavage; a complex of PAP and PF
I, which includes CF II subunits, participates in polyadenylation, along with CF I. These factors are directed to the appropriate site on
the mRNA by two sequences: one A-rich and one UA-rich. CF I contains
five proteins, two of which, Rna15 and Hrp1, interact with the mRNA
through RNA recognition motif-type RNA binding motifs. Previous work
demonstrated that the UV cross-linking of purified Hrp1 to RNA required
the UA-rich element, but the contact point of Rna15 was not known. We
show here that Rna15 does not recognize a particular sequence in the
absence of other proteins. However, in complex with Hrp1 and Rna14,
Rna15 specifically interacts with the A-rich element. The Pcf11 and
Clp1 subunits of CF I are not needed to position Rna15 at this site.
This interaction is essential to the function of CF I. A mutant Rna15
with decreased affinity for RNA is defective for in vitro RNA
processing and lethal in vivo, while an RNA with a mutation in the
A-rich element is not processed in vitro and can no longer be UV
cross-linked to the Rna15 subunit assembled into CF I. Thus, the
recognition of the A-rich element depends on the tethering of Rna15
through an Rna14 bridge to Hrp1 bound to the UA-rich motif. These
results illustrate that the yeast 3' end is defined and processed by a
mechanism surprisingly different from that used by the mammalian system.
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.23.8045-8055.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Rna15 Interaction with the A-Rich Yeast
Polyadenylation Signal Is an Essential Step in mRNA 3'-End
Formation
*
Corresponding author. Mailing address: Department of
Molecular Biology and Microbiology, Sackler School of Graduate
Biomedical Sciences, Tufts University, 136 Harrison Ave., Boston, MA
02111. Phone: (617) 636-3645. Fax: (617) 636-0337. E-mail:
claire.moore{at}tufts.edu.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|