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Masking mRNA from translation in somatic cells
M Ranjan1, S R Tafuri, A P Wolffe
1Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
Abstract:
We present evidence for a role for Y-box proteins in both mRNA transcription and translation. We have expressed an oocyte-specific RNA-binding protein (FRGY2) in somatic cells. This protein is normally found together with mRNA in large amounts within the masked maternal mRNA storage particles of Xenopus laevis oocytes. Masked maternal mRNA is believed to be translationally repressed during oogenesis and is stored within ribonucleoprotein storage particles for subsequent use during embryogenesis. Surprisingly, FRGY2 is not only found to direct the accumulation of mRNA from promoters containing binding sites for the protein but also to selectively repress translation of the same mRNA. Thus, the role of FRGY2 in the transcription and storage of maternal mRNA is similar to that of the transcription factor TFIIIA in the transcription and storage of 5S rRNA from the oocyte type 5S rRNA genes.
Insights
Y-box proteins, like FRGY2, regulate both mRNA transcription and translation. This RNA-binding protein directs mRNA accumulation and selectively represses its translation, similar to TFIIIA's role in rRNA storage.
Area of Science:
- Molecular Biology
- Developmental Biology
- RNA Biology
Background:
- Y-box proteins are RNA-binding proteins involved in various RNA regulation processes.
- Masked maternal mRNA in Xenopus laevis oocytes is translationally repressed and stored in ribonucleoprotein particles.
- FRGY2 is an oocyte-specific Y-box protein found in these maternal mRNA storage particles.
Purpose of the Study:
- To investigate the role of the oocyte-specific RNA-binding protein FRGY2 in mRNA transcription and translation.
- To determine if FRGY2, when expressed in somatic cells, exhibits regulatory functions on mRNA.
- To compare the function of FRGY2 in mRNA regulation to transcription factor TFIIIA's role in rRNA regulation.
Main Methods:
- Expression of the Xenopus laevis oocyte-specific RNA-binding protein FRGY2 in somatic cells.
- Analysis of mRNA accumulation from promoters containing FRGY2 binding sites.
- Assessment of FRGY2's effect on the translation of associated mRNA.
Main Results:
- FRGY2 expression in somatic cells led to the accumulation of mRNA from promoters with binding sites.
- FRGY2 was found to selectively repress the translation of the same mRNA it promoted.
- The dual role of FRGY2 in transcription and translational repression mirrors TFIIIA's function in 5S rRNA gene regulation.
Conclusions:
- Y-box proteins, exemplified by FRGY2, play a dual role in regulating both mRNA transcription and translation.
- FRGY2 acts as a regulatory factor influencing mRNA levels and translational activity.
- The findings suggest a conserved mechanism for regulating gene expression involving Y-box proteins in both mRNA and rRNA pathways.