Abstract
The pioneer round of translation plays a role in translation initiation of newly spliced and exon junction complex (EJC)-bound mRNAs. Nuclear cap-binding protein complex CBP80/20 binds to those mRNAs at the 5′-end, recruiting translation initiation complex. As a consequence of the pioneer round of translation, the bound EJCs are dissociated from mRNAs and CBP80/20 is replaced by the cytoplasmic cap-binding protein eIF4E. Steady-state translation directed by eIF4E allows for an immediate and rapid response to changes in physiological conditions. Here, we show that nonsense-mediated mRNA decay (NMD), which restricts only to the pioneer round of translation but not to steady-state translation, efficiently occurs even during serum starvation, in which steady-state translation is drastically abolished. Accordingly, CBP80 remains in the nucleus and processing bodies are unaffected in their abundance and number in serum-starved conditions. These results suggest that mRNAs enter the pioneer round of translation during serum starvation and are targeted for NMD if they contain premature termination codons.
Original language | English |
---|---|
Pages (from-to) | 145-151 |
Number of pages | 7 |
Journal | Biochemical and biophysical research communications |
Volume | 362 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2007 Oct 12 |
Bibliographical note
Funding Information:We thank Lynne E. Maquat for providing NMD reporter constructs and α-Upf antibodies, Robin Reed for α-CBP80 antibody and α-eIF4AIII antibody, John W. Hershey for α-eIF3 antibody, Sung Key Jang for α-eIF4GI antibody, and Jens Lykke-Andersen for pCDNA3-FLAG-Dcp1a. We also thank Incheol Ryu for helpful comments. This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD)” (KRF-2006-311-E00204), a grant of the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (A062356), and a grant (20070301034003) from BioGreen 21 Program, Rural Development Administration, Republic of Korea.
Keywords
- CBP80
- Nonsense-mediated mRNA decay
- Pioneer round of translation
- Processing body
- Serum starvation
- Steady-state translation
- Stress granule
- eIF4E
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology