Volume 13 Supplement 18
Unexpected variations in translation initiation machinery
© Lim et al; licensee BioMed Central Ltd. 2012
Published: 14 December 2012
In prokaryotes, the Shine-Dalgarno (SD) sequence in the 5’ untranslated region (UTR) of mRNA forms a duplex with the anti-Shine-Dalgarno (anti-SD) sequence to initiate translation . The mechanism has been regarded as universal, as the core of the anti-SD sequence (5’-CCTCC-3’, anti-SD motif) is completely conserved in every prokaryote genome according to previous reports . Recent accelerated accumulation of complete genomic sequences motivated us to conduct an updated screening for anti-SD sequence variants.
The non-anti-SD genomes we reported here represent an extreme aspect of the dynamic evolution in the translation initiation mechanisms, strongly indicating extinction of SD/anti-SD interaction in some bacterial lineages. Attentive analysis of such peculiar genomes led us to suggest likely factors that gave rise to the loss. First, advanced association with eukaryotic hosts and subsequent immense genomic/functional reduction. Second, intra-genomic dominance of SD-independent translation initiation mechanisms. Finally, hemotropic environment.
Our study described here has been published as an original research article .
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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.