Comprehensive phylogenetic analysis of bacterial reverse transcriptases

Area of Science:

• Microbiology
• Molecular Biology
• Genomics

Background:

• Reverse transcriptases (RTs) are crucial enzymes, yet their roles in prokaryotes remain largely uncharacterized compared to eukaryotes.
• Previous surveys indicated a significant number of unannotated RT and RT-like sequences in prokaryotic genomes.

Purpose of the Study:

• To compile and analyze annotated reverse transcriptase sequences from completely sequenced bacterial genomes.
• To classify bacterial RTs and understand their distribution and diversity across different bacterial phyla.

Main Methods:

• Utilized consistent annotation across bacterial genomes via the RAST system on the PATRIC platform.
• Performed BLAST searches to identify RT genes and conducted phylogenetic analyses for classification.

Main Results:

• RT sequences are broadly distributed in bacteria, with high diversity observed in green sulfur bacteria and cyanobacteria.
• Bacterial RTs were classified into 17 distinct groups, including group II introns, retrons, and diversity-generating retroelements (DGRs).
• Proteobacteria exhibited the highest potential functional diversity, and group II introns and DGRs were the most prevalent.

Conclusions:

• This comprehensive analysis provides a phylogenetic framework for bacterial RTs.
• The findings offer a basis for improving annotation systems for these enzymes in prokaryotes.