RpS3 translation is repressed by interaction with its own mRNA
Article first published online: 9 MAR 2010
Copyright © 2010 Wiley-Liss, Inc.
Journal of Cellular Biochemistry
Volume 110, Issue 2, pages 294–303, 15 May 2010
How to Cite
Kim, H. D., Kim, T.-S., Joo, Y. J., Shin, H.-S., Kim, S.-H., Jang, C.-Y., Lee, C. E. and Kim, J. (2010), RpS3 translation is repressed by interaction with its own mRNA. J. Cell. Biochem., 110: 294–303. doi: 10.1002/jcb.22537
- Issue published online: 21 APR 2010
- Article first published online: 9 MAR 2010
- Manuscript Accepted: 15 JAN 2010
- Manuscript Received: 4 APR 2009
- KRF. Grant Numbers: 07-314-C00129, 07-005-J03603
- Proteomics. Grant Number: FPR08B1-230
- KH domain
Ribosomal protein S3 (RpS3) is a well-known multi-functional protein mainly involved in protein biosynthesis as a member of the small ribosomal subunit. It also plays a role in repairing various DNA damage acting as a repair UV endonuclease. Most of the rpS3 pool is located in the ribosome while the minority exists in free form in the cytoplasm. We here report an additional function of rpS3 in which it represses its own translation by binding to its cognate mRNA. Through RT-PCR of the RNAs co-immunoprecipitated with ectopically expressed rpS3, rpS3 protein was found to interact with various RNAs—endogenous rpS3, 18S rRNA. The S3-C terminal domain was shown to be the major mRNA binding domain of rpS3, independent of the KH domain. This interaction was shown to occur in cytoplasmic fractions rather than ribosomal fractions, and then is involved in its own mRNA translational inhibition by in vitro translation. Furthermore, when Flag-tagged rpS3 was transiently transfected into 293T cells, the level of endogenous rpS3 gradually decreased regardless of transcription. These results suggest that free rpS3 regulates its own translation via a feedback mechanism. J. Cell. Biochem. 110: 294–303, 2010. © 2010 Wiley-Liss, Inc.