Genetic Codes with No Dedicated Stop Codon: Context-Dependent Translation Termination

The prevailing view of the nuclear genetic code is that it is largely frozen and unambiguous. Flexibility in the nuclear genetic code has been demonstrated in ciliates that reassign standard stop codons to amino acids, resulting in seven variant genetic codes, including three previously undescribed ones reported here. Surprisingly, in two of these species, we find efficient translation of all 64 codons as standard amino acids and recognition of either one or all three stop codons. How, therefore, does the translation machinery interpret a “stop” codon? We provide evidence, based on ribosomal profiling and “stop” codon depletion shortly before coding sequence ends, that mRNA 3′ ends may contribute to distinguishing stop from sense in a context-dependent manner. We further propose that such context-dependent termination/readthrough suppression near transcript ends enables genetic code evolution.

Standardized reporting using CODES (Crash Outcome Data Evaluation System).

National Highway Traffic Safety Administration, Washington, D.C.

The Civil Code of the Federal District and territories. A translation, with an appendix as to the civil codes of the various Mexican states, explanatory notes, etc.

Index: p. [i]-ix.

Tabulation of labor provisions in codes approved by August 8, 1934.

Mode of access: Internet.

Housing codes : the key to housing conservation /

Cover title.

Housing codes : the key to housing conservation : a demonstration project /

Cover title.

Codes of fair competition as approved

Mode of access: Internet.

The crash outcome data evaluation system (CODES).

National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.