High transcriptional activity of insertion sequences in Baltic Sea microorganisms
(English)Manuscript (preprint) (Other academic)
Insertion sequences (ISs) are mobile genetic elements found in almost all prokaryotic genomes. They consist of a gene encoding a transposase, surrounded by inverted repeats. The transposase has the ability to excise the IS and insert it elsewhere in the genome, a process referred to as transposition. ISs have high copy numbers in prokaryotes inhabiting “extreme” environments, and it is proposed that their activity facilitates adaptation to environmental changes and subsequent adaptive evolution. The initial step in the transposition of an IS is the transcription of the open reading frame encoding the transposase. In an effort to evaluate the presence, activity and role of ISs in microbes of a temperate water body offering steep changes in salinity and nutrient conditions, the metatranscriptomes and metagenomes of ten water samples from the brackish water Baltic Sea were examined. ISs in the limnic Lake Torne Träsk, the marine waters off the Swedish west coast and off the coast of California were included to get perspective. The results reveal that insertion sequences make up a considerably higher fraction of the metatranscriptomes of brackish waters (0.3-1.8%) than of marine waters (0.0005-0.2%), and that the IS fraction of the metatranscriptome is commonly double that of the IS fraction of the metagenome. From these data it is concluded that ISs occupy a significant part of Baltic Sea bacterial transcription activity, in line with their proposed function as facilitators of adaptive change to changing and stressful environments.
Research subject Plant Physiology
IdentifiersURN: urn:nbn:se:su:diva-117088OAI: oai:DiVA.org:su-117088DiVA: diva2:810169