Premium
A Functional Interaction between the Evolutionarily Conserved Zinc Finger Poly(A) RNA‐binding Protein, Nab2, and the Exosome Links mRNA 3′‐End Processing/Export with mRNA Quality Control
Author(s) -
Fasken Milo,
Corbett Anita H
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.666.1
Subject(s) - biology , rna , messenger rna , biochemistry , microbiology and biotechnology , gene
Quality control of mRNA processing and export ensures that only properly processed transcripts reach the cytoplasm. A key player in RNA quality control is the exosome, a riboexonuclease complex with a critical catalytic subunit, Dis3, that degrades or trims RNA. In S. cerevisiae , the essential zinc finger poly(A) RNA binding protein, Nab2, plays important roles in the control of mRNA poly(A) tail length and export. The N‐terminal domain of Nab2 (Nab2‐N), which is critical for Nab2 function, forms a five alpha‐helix bundle with a proline‐tryptophan‐isoleucine (PWI)‐like fold found in several RNA‐binding proteins including ZC3H14, a putative human orthologue of Nab2. Expression of a Nab2 deletion mutant, Nab2 δN, causes slow growth, extended poly(A) tails and a block to poly(A) RNA export. To gain insight into the role of Nab2‐N and the function of this evolutionarily conserved protein family, we performed a transposon mutagenesis screen on nab2 δN cells to identify extragenic suppressors that rescue nab2 δN cell growth. This screen identified transposon insertions in two genes that encode essential components of the exosome, DIS3 and RRP4 , revealing that Nab2 genetically interacts with the exosome and suggesting that Nab2 may physically associate with this riboexonuclease machine. Thus, Nab2 may recruit the exosome to modulate poly(A) tail length and target improperly processed mRNA for degradation.