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Predominance of six different hexanucleotide recoding signals 3' of read-through stop codons
Lance Harrell1, Ulrich Melcher, John F Atkins
1Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
Nucleic Acids Research
|April 25, 2002
Summary
Gene expression utilizes mRNA recoding signals to alter stop codon meaning, enabling protein synthesis. This study identifies specific sequences that enhance this "read-through" process in viruses.
Area of Science:
- Molecular Biology
- Genetics
- Virology
Background:
- Specific mRNA sequences can override standard stop codons (UAG, UAA, UGA), leading to the incorporation of amino acids.
- This programmed ribosomal 'read-through' is a mechanism for gene expression, competing with translation termination.
Purpose of the Study:
- To investigate the role of sequences downstream of stop codons in viral mRNA read-through.
- To identify common sequence motifs that promote read-through in viral genomes.
Main Methods:
- Analysis of 91 unique viral sequences annotated for read-through.
- Utilizing a dual luciferase fusion reporter system in mammalian tissue culture cells to quantify read-through efficiency.
Main Results:
- 90% of analyzed viral read-through sequences featured one of six specific codons immediately downstream of the stop codon.
- The study determined the relative efficiency of various hexanucleotide contexts in promoting read-through.
Conclusions:
- Specific sequence contexts downstream of viral stop codons significantly influence programmed ribosomal read-through.
- The efficiency of read-through is complex and depends on the precise nucleotide identity within these hexanucleotide signals.