Document Type
Article
Publication Date
12-8-2016
Abstract
BACKGROUND: While the CCA sequence at the mature 3' end of tRNAs is conserved and critical for translational function, a genetic template for this sequence is not always contained in tRNA genes. In eukaryotes and Archaea, the CCA ends of tRNAs are synthesized post-transcriptionally by CCA-adding enzymes. In Bacteria, tRNA genes template CCA sporadically.
RESULTS: In order to understand the variation in how prokaryotic tRNA genes template CCA, we re-annotated tRNA genes in tRNAdb-CE database version 0.8. Among 132,129 prokaryotic tRNA genes, initiator tRNA genes template CCA at the highest average frequency (74.1%) over all functional classes except selenocysteine and pyrrolysine tRNA genes (88.1% and 100% respectively). Across bacterial phyla and a wide range of genome sizes, many lineages exist in which predominantly initiator tRNA genes template CCA. Convergent and parallel retention of CCA templating in initiator tRNA genes evolved in independent histories of reductive genome evolution in Bacteria. Also, in a majority of cyanobacterial and actinobacterial genera, predominantly initiator tRNA genes template CCA. We also found that a surprising fraction of archaeal tRNA genes template CCA.
CONCLUSIONS: We suggest that cotranscriptional synthesis of initiator tRNA CCA 3' ends can complement inefficient processing of initiator tRNA precursors, "bootstrap" rapid initiation of protein synthesis from a non-growing state, or contribute to an increase in cellular growth rates by reducing overheads of mass and energy to maintain nonfunctional tRNA precursor pools. More generally, CCA templating in structurally non-conforming tRNA genes can afford cells robustness and greater plasticity to respond rapidly to environmental changes and stimuli.
Recommended Citation
Ardell, David H. and Hou, Ya-Ming, "Initiator tRNA genes template the 3' CCA end at high frequencies in bacteria." (2016). Department of Biochemistry and Molecular Biology Faculty Papers. Paper 108.
https://jdc.jefferson.edu/bmpfp/108
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
PubMed ID
27927177
Comments
This article has been peer reviewed. It is the author’s final published version in BMC Genomics
Volume 17, Issue 1, December 2016, Article number 1003.
The published version is available at DOI: 10.1186/s12864-016-3314-x. Copyright © Ardell & Hou