Related Experiment Videos
Translational inactivation of ribosomal protein mRNAs during Xenopus oocyte maturation
1Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254.
Abstract:
Ribosomal protein synthesis ceases upon maturation of Xenopus oocytes. We find that this cessation results from the dissociation of ribosomal protein mRNAs from polysomes and is accompanied by the deadenylation of these transcripts. A synthetic mRNA encoding ribosomal protein L1, microinjected into stage VI oocytes, is deadenylated and released from polysomes upon maturation. Our results indicate that sequences located within 387 bp of the 3' terminus of L1 mRNA direct both the deadenylation and polysomal release of this ribosomal protein mRNA. The proper translational regulation of an exogenous ribosomal protein mRNA in microinjected oocytes provides a basis for determining the sequence specificity for the differential utilization of maternal mRNAs during oocyte maturation.
Insights
Ribosomal protein synthesis stops in maturing Xenopus oocytes due to ribosomal protein messenger RNAs (mRNAs) detaching from polysomes. Specific 3' end sequences of L1 mRNA control this deadenylation and release process.
Area of Science:
- Developmental Biology
- Molecular Biology
- Xenopus Oocyte Maturation
Background:
- Ribosomal protein synthesis is crucial for cell function but is transcriptionally repressed during Xenopus oocyte maturation.
- The precise mechanisms regulating translational control of ribosomal protein mRNAs during this developmental transition are not fully understood.
Purpose of the Study:
- To investigate the molecular mechanisms underlying the cessation of ribosomal protein synthesis during Xenopus oocyte maturation.
- To identify specific sequences within ribosomal protein mRNA that regulate translational control.
Main Methods:
- Microinjection of synthetic ribosomal protein L1 mRNA into stage VI Xenopus oocytes.
- Analysis of mRNA deadenylation and polysomal association during oocyte maturation.
- Mapping of regulatory sequences within the 3' terminus of L1 mRNA.
Main Results:
- Ribosomal protein synthesis cessation is linked to the dissociation of ribosomal protein mRNAs from polysomes and their deadenylation.
- Microinjected L1 mRNA undergoes deadenylation and polysomal release upon oocyte maturation.
- Sequences within 387 bp of the 3' terminus of L1 mRNA are sufficient to direct deadenylation and polysomal release.
Conclusions:
- The translational regulation of ribosomal protein mRNAs during oocyte maturation involves mRNA deadenylation and polysomal release.
- Specific 3' terminal sequences of L1 mRNA mediate these regulatory events.
- This study provides a foundation for identifying sequence specificities governing maternal mRNA utilization in oocyte development.