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11:19
Novel RNA-Binding Proteins Isolation by the RaPID Methodology
Published on: September 30, 2016
RpS3 translation is repressed by interaction with its own mRNA
Hag Dong Kim1, Tae-Sung Kim, Yoo Jin Joo
1Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul, South Korea.
Journal of Cellular Biochemistry
|March 11, 2010
Summary
Ribosomal protein S3 (RpS3) has a new function: repressing its own translation. Free RpS3 binds to its mRNA, acting as a feedback mechanism to regulate protein levels.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Ribosomal protein S3 (RpS3) is primarily known for its roles in protein biosynthesis and DNA repair.
- A small fraction of RpS3 exists in a free form in the cytoplasm, separate from ribosomal complexes.
Purpose of the Study:
- To investigate potential novel functions of free ribosomal protein S3 (RpS3).
- To determine if RpS3 regulates its own gene expression or translation.
Main Methods:
- RNA immunoprecipitation followed by RT-PCR to identify RNAs interacting with RpS3.
- In vitro translation assays to assess the effect of RpS3 on its mRNA.
- Transient transfection of cells with Flag-tagged RpS3 to monitor endogenous RpS3 levels.
Main Results:
- RpS3 was found to interact with its own mRNA and 18S rRNA in cytoplasmic fractions.
- The C-terminal domain of RpS3, independent of the KH domain, mediates mRNA binding.
- In vitro translation assays demonstrated that RpS3 inhibits its own mRNA translation.
- Overexpression of Flag-tagged RpS3 led to decreased levels of endogenous RpS3, independent of transcription.
Conclusions:
- Free RpS3 functions as a translational repressor of its own mRNA.
- This represents a novel feedback mechanism for regulating RpS3 protein levels.
- RpS3's functions extend beyond ribosomal activity and DNA repair to include translational autoregulation.
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