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RNA Isolation from Embryonic Zebrafish and cDNA Synthesis for Gene Expression Analysis
Published on: August 7, 2009
Recycling of Uridylated mRNAs in Starfish Embryos
Haruka Yamazaki1, Megumi Furuichi1, Mikoto Katagiri1
1Department of Biological Sciences, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, Japan.
Abstract:
In eukaryotes, mRNAs with long poly(A) tails are translationally active, but deadenylation and uridylation of these tails generally cause mRNA degradation. However, the fate of uridylated mRNAs that are not degraded quickly remains obscure. Here, using tail-seq and microinjection of the 3' region of mRNA, we report that some mRNAs in starfish are re-polyadenylated to be translationally active after deadenylation and uridylation. In oocytes, uridylated maternal cyclin B mRNAs are stable without decay, and they are polyadenylated to be translated after hormonal stimulation to resume meiosis, whereas they are deadenylated and re-uridylated at the blastula stage, followed by decay. Similarly, deadenylated and uridylated maternal ribosomal protein mRNAs, Rps29 and Rpl27a, were stable and inactive after hormonal stimulation, but they had been polyadenylated and active before hormonal stimulation. At the morula stage, uridylated maternal ribosomal protein mRNAs were re-polyadenylated, rendering them translationally active. These results indicate that uridylated mRNAs in starfish exist in a poised state, allowing them to be recycled or decayed.
Insights
Uridylated mRNAs in starfish can be reactivated for translation after being deactivated. This research reveals a poised state for uridylated mRNAs, allowing for recycling or degradation.
Area of Science:
- Molecular Biology
- Developmental Biology
- RNA Biology
Background:
- In eukaryotes, mRNA poly(A) tail length regulates translation and degradation.
- Deadenylation and uridylation typically lead to mRNA decay.
- The fate of uridylated mRNAs not immediately degraded is largely unknown.
Purpose of the Study:
- To investigate the post-deadenylation/uridylation fate of mRNAs in starfish.
- To determine if uridylated mRNAs can regain translational activity.
- To understand the regulatory mechanisms of maternal mRNA during early development.
Main Methods:
- Tail sequencing (tail-seq) to analyze poly(A) tail dynamics.
- Microinjection of mRNA 3' regions to study regulatory elements.
- Observation of maternal mRNA behavior (cyclin B, Rps29, Rpl27a) during starfish development.
Main Results:
- Starfish mRNAs can be re-polyadenylated and become translationally active after deadenylation and uridylation.
- Uridylated maternal cyclin B mRNA is stable in oocytes and re-polyadenylated upon hormonal stimulation.
- Uridylated ribosomal protein mRNAs (Rps29, Rpl27a) are inactive but can be re-polyadenylated at the morula stage.
Conclusions:
- Uridylated mRNAs in starfish exist in a poised state, not necessarily destined for immediate degradation.
- This poised state allows for the selective recycling or decay of specific maternal mRNAs.
- mRNA polyadenylation and uridylation dynamics play a crucial role in regulating gene expression during development.
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