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Bioinformatic Prediction of an tRNASec Gene Nested inside an Elongation Factor SelB Gene in Alphaproteobacteria

Authors :
Takahito Mukai
Source :
International Journal of Molecular Sciences, International Journal of Molecular Sciences, Vol 22, Iss 4605, p 4605 (2021)
Publication Year :
2021
Publisher :
MDPI, 2021.

Abstract

In bacteria, selenocysteine (Sec) is incorporated into proteins via the recoding of a particular codon, the UGA stop codon in most cases. Sec-tRNASec is delivered to the ribosome by the Sec-dedicated elongation factor SelB that also recognizes a Sec-insertion sequence element following the codon on the mRNA. Since the excess of SelB may lead to sequestration of Sec-tRNASec under selenium deficiency or oxidative stress, the expression levels of SelB and tRNASec should be regulated. In this bioinformatic study, I analyzed the Rhizobiales SelB species because they were annotated to have a non-canonical C-terminal extension. I found that the open reading frame (ORF) of diverse Alphaproteobacteria selB genes includes an entire tRNASec sequence (selC) and overlaps with the start codon of the downstream ORF. A remnant tRNASec sequence was found in the Sinorhizobium melilotiselB genes whose products have a shorter C-terminal extension. Similar overlapping traits were found in Gammaproteobacteria and Nitrospirae. I hypothesized that once the tRNASec moiety is folded and processed, the expression of the full-length SelB may be repressed. This is the first report on a nested tRNA gene inside a protein ORF in bacteria.

Details

Language :
English
ISSN :
14220067
Volume :
22
Issue :
9
Database :
OpenAIRE
Journal :
International Journal of Molecular Sciences
Accession number :
edsair.doi.dedup.....0acbd1601ac3ea5b739b6ceeac52b7cc