title: The Cyanobacterial Ribosomal-Associated Protein LrtA Is Involved in Post-Stress Survival in Synechocystis sp. PCC 6803.
abstract: A light-repressed transcript encodes the LrtA protein in cyanobacteria. We show that half-life of lrtA transcript from Synechocystis sp. PCC 6803 is higher in dark-treated cells as compared to light-grown cells, suggesting post-transcriptional control of lrtA expression. The lrtA 5´ untranslated leader region is involved in that darkness-dependent regulation. We also found that Synechocystis sp. PCC 6803 LrtA is a ribosome-associated protein present in both 30S and 70S ribosomal particles. In order to investigate the function of this protein we have constructed a deletion mutant of the lrtA gene. Cells lacking LrtA (∆lrtA) had significantly lower amount of 70S particles and a greater amount of 30S and 50S particles, suggesting a role of LrtA in stabilizing 70S particles. Synechocystis strains with different amounts of LrtA protein: wild-type, ∆lrtA, and LrtAS (overexpressing lrtA) showed no differences in their growth rate under standard laboratory conditions. However, a clear LrtA dose-dependent effect was observed in the presence of the antibiotic tylosin, being the LrtAS strains the most sensitive. Similar results were obtained under hyperosmotic stress caused by sorbitol. Conversely, after prolonged periods of starvation, ∆lrtA strains were delayed in their growth with respect to the wild-type and the LrtAS strains. A positive role of LrtA protein in post-stress survival is proposed.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain.
authors.forename: Carla V
authors.initials: CV
authors.lastname: Galmozzi
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Florencio
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain.
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Muro-Pastor
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D050296:Microbial Viability / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology; D013012:Sorbitol / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D046939:Synechocystis / Q000235:genetics / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects; D015645:Tylosin / Q000494:pharmacology
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C088911:lrtA protein, Synechococcus sp.; D012965:Sodium Chloride; D013012:Sorbitol; D015645:Tylosin