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Updated: May 19, 2026

Genetic Modification of Cyanobacteria by Conjugation Using the CyanoGate Modular Cloning Toolkit
Published on: October 31, 2019
Expression and processing of an unusual tRNA gene cluster in the cyanobacterium Anabaena sp. PCC 7120
Leonor Puerto-Galán1, Agustín Vioque
1Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and CSIC, Sevilla, Spain.
Abstract:
Anabaena sp. PCC 7120 is a filamentous cyanobacterium that bears a cluster of 26 tRNA genes and pseudogenes in the delta plasmid. The sequences of these tRNAs suggest that they have been acquired by horizontal gene transfer from another organism. The cluster is transcribed as a single transcript that is quickly processed to individual tRNAs. RNase P and RNase Z, in vitro, are able to process precursors containing some of these tRNAs. Deletion of the cluster causes no obvious phenotype or effect on growth under diverse culture conditions, indicating that the tRNAs encoded in the cluster are not required for growth under laboratory conditions, although they are aminoacylated in vivo. We have studied a possible tRNA(Ser) [tRNA(Ser) GCU(2)] present in the cluster with a sequence that deviates from consensus. This tRNA is processed in vitro by RNase P at the expected position. In addition, this tRNA(Ser) GCU is specifically aminoacylated with serine by an Anabaena sp. PCC 7120 crude extract. These data indicate that tRNA(Ser) GCU(2) is fully functional, despite its unusual structure. Similar clusters are found in other three cyanobacteria whose genomes have been sequenced.
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