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Alternative Translation Initiation of a Haloarchaeal Serine Protease Transcript Containing Two In-Frame Start Codons
- Source :
- Journal of Bacteriology. 198:1892-1901
- Publication Year :
- 2016
- Publisher :
- American Society for Microbiology, 2016.
-
Abstract
- Recent studies have shown that haloarchaea employ leaderless and Shine-Dalgarno (SD)-less mechanisms for translation initiation of leaderless transcripts with a 5′ untranslated region (5′ UTR) of sptA gene (encoding an extracellular serine protease of Natrinema sp. strain J7-2) was experimentally determined and found to contain two potential in-frame AUG codons (AUG 1 and AUG 2 ) located 5 and 29 nt, respectively, downstream of the transcription start site. Mutational analysis revealed that both AUGs can function as the translation start codon for production of active SptA, although AUG 1 is more efficient than AUG 2 for translation initiation. Insertion of a stable stem-loop structure between the two AUGs completely abolished initiation at AUG 1 but did not affect initiation at AUG 2 , indicating that AUG 2 -initiated translation does not involve ribosome scanning from the 5′ end of the transcript. Furthermore, the efficiency of AUG 2 -initiated translation was not influenced by an upstream SD-like sequence. In addition, both AUG 1 and AUG 2 contribute to transcript stability, probably by recruiting ribosomes to protect the transcript against degradation. These data suggest that depending on which of two in-frame start codons is used, the sptA transcript can act as either a leaderless or a leadered transcript for SptA production in haloarchaea. IMPORTANCE In eukaryotes and bacteria, alternative translation start sites contribute to proteome complexity and can be used as a functional mechanism to increase translation efficiency. However, little is known about alternative translation initiation in archaea. Our results demonstrate that leaderless and SD-less mechanisms can be used for translation initiation of the sptA transcript from two in-frame start codons, raising the possibility that in haloarchaea, alternative translation initiation on one transcript functions to increase translation efficiency and/or contribute to proteome complexity.
- Subjects :
- 0301 basic medicine
Untranslated region
Archaeal Proteins
Molecular Sequence Data
030106 microbiology
Codon, Initiator
Euryarchaeota
Biology
Microbiology
Ribosome
03 medical and health sciences
Eukaryotic translation
Start codon
Protein biosynthesis
Peptide Chain Initiation, Translational
Promoter Regions, Genetic
Molecular Biology
Gene
Genetics
Base Sequence
Translation (biology)
Articles
biology.organism_classification
Protein Biosynthesis
Haloarchaea
Serine Proteases
Subjects
Details
- ISSN :
- 10985530 and 00219193
- Volume :
- 198
- Database :
- OpenAIRE
- Journal :
- Journal of Bacteriology
- Accession number :
- edsair.doi.dedup.....54066123be46aa6609ccbf4b4c5d81ec