In vitro selection of translational regulatory elements.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Untranslated regions (UTRs) of messenger RNAs (mRNAs) contain regulatory elements influencing translation.
• Current understanding of these translational regulatory elements within UTRs is limited.
• Systematic identification of such elements is crucial for understanding gene expression control.

Purpose of the Study:

• To develop and validate a novel in vitro selection system, SESTRE (Systematic Enrichment of Sequences That Alter Translation Efficiency), for identifying translational regulatory elements.
• To investigate the emergence and location of translational enhancer motifs in eukaryotic mRNAs.
• To explore the influence of the 5' cap on the evolution of translational enhancers.

Main Methods:

• Introduction of random nucleotide sequences into the UTRs of target mRNAs.
• In vitro translation using wheat germ extract.
• Size fractionation of polyribosomes to isolate actively translating complexes.
• Reverse transcription and PCR amplification (RT-PCR) for sequence enrichment.
• Iterative cycles of selection and amplification to enrich for sequences that enhance or inhibit translation.

Main Results:

• The SESTRE method successfully enriched for sequences that alter mRNA translation efficiency.
• Translational enhancer motifs were found to emerge differentially based on the presence or absence of the 5' cap.
• Cap-independent translational enhancers were observed to evolve more readily in the 3' UTR compared to the 5' UTR in the wheat germ extract system.

Conclusions:

• The SESTRE system is a powerful tool for the systematic identification of translational regulatory elements in eukaryotic mRNAs.
• Understanding the role of UTRs and the 5' cap in translational control can be advanced using this method.
• This approach has potential applications in improving mRNA translational efficiency for biotechnology and research purposes.