TY - JOUR
T1 - Aberrant mRNA Transcripts and the Nonsense-Mediated Decay Proteins UPF2 and UPF3 Are Enriched in the Arabidopsis Nucleolus
AU - Kim, Sang Hyon
AU - Koroleva, Olga A.
AU - Lewandowska, Dominika
AU - Pendle, Ali F.
AU - Clark, Gillian P.
AU - Simpson, Craig G.
AU - Shaw, Peter J.
AU - Brown, John W. S.
PY - 2009/7
Y1 - 2009/7
N2 - The eukaryotic nucleolus is multifunctional and involved in the metabolism and assembly of many different RNAs and ribonucleoprotein particles as well as in cellular functions, such as cell division and transcriptional silencing in plants. We previously showed that Arabidopsis thaliana exon junction complex proteins associate with the nucleolus, suggesting a role for the nucleolus in mRNA production. Here, we report that the plant nucleolus contains mRNAs, including fully spliced, aberrantly spliced, and single exon gene transcripts. Aberrant mRNAs are much more abundant in nucleolar fractions, while fully spliced products are more abundant in nucleoplasmic fractions. The majority of the aberrant transcripts contain premature termination codons and have characteristics of nonsense-mediated decay (NMD) substrates. A direct link between NMD and the nucleolus is shown by increased levels of the same aberrant transcripts in both the nucleolus and in Up-frameshift (upf) mutants impaired in NMD. In addition, the NMD factors UPF3 and UPF2 localize to the nucleolus, suggesting that the Arabidopsis nucleolus is therefore involved in identifying aberrant mRNAs and NMD.
AB - The eukaryotic nucleolus is multifunctional and involved in the metabolism and assembly of many different RNAs and ribonucleoprotein particles as well as in cellular functions, such as cell division and transcriptional silencing in plants. We previously showed that Arabidopsis thaliana exon junction complex proteins associate with the nucleolus, suggesting a role for the nucleolus in mRNA production. Here, we report that the plant nucleolus contains mRNAs, including fully spliced, aberrantly spliced, and single exon gene transcripts. Aberrant mRNAs are much more abundant in nucleolar fractions, while fully spliced products are more abundant in nucleoplasmic fractions. The majority of the aberrant transcripts contain premature termination codons and have characteristics of nonsense-mediated decay (NMD) substrates. A direct link between NMD and the nucleolus is shown by increased levels of the same aberrant transcripts in both the nucleolus and in Up-frameshift (upf) mutants impaired in NMD. In addition, the NMD factors UPF3 and UPF2 localize to the nucleolus, suggesting that the Arabidopsis nucleolus is therefore involved in identifying aberrant mRNAs and NMD.
UR - http://www.scopus.com/inward/record.url?scp=69949191661&partnerID=8YFLogxK
U2 - 10.1105/tpc.109.067736
DO - 10.1105/tpc.109.067736
M3 - Article
C2 - 19602621
VL - 21
SP - 2045
EP - 2057
JO - Plant Cell
JF - Plant Cell
SN - 1040-4651
IS - 7
ER -