Send to

Choose Destination
Nucleic Acids Res. 1990 Nov 11;18(21):6339-45.

Sequence analysis suggests that tetra-nucleotides signal the termination of protein synthesis in eukaryotes.

Author information

Department of Biochemistry, University of Otago, Dunedin, New Zealand.


An increasing number of cases where tri-nucleotide stop codons do not signal the termination of protein synthesis are being reported. In order to identify what constitutes an efficient stop signal, we analysed the region around natural stop codons in genes from a wide variety of eukaryotic species and gene families. Certain stop codons and nucleotides following stop codons are over-represented, and this pattern is accentuated in highly expressed genes. For example, the preferred signal for Saccharomyces cerevisiae and Drosophila melanogaster highly expressed genes is UAAG, and generally the signals UAA(A/G) and UGA(A/G) are preferred in eukaryotes. The GC% of the organism or DNA region can affect whether there is A or G in the second or fourth positions. We suggest therefore, that the stop codon and the nucleotide following it comprise a tetra-nucleotide stop signal. A model is proposed in which the polypeptide chain release factor, a protein, recognises this sequence, but will tolerate some substitution, particularly A to G in the second or third positions.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center