IMPACTO DE LA RELOCALIZACIÓN DE GENES IMPLICADOS EN EL FLUJO DE LA INFORMACIÓN GENÉTICA EN EL CRECIMIENTO BACTERIANO Y LA APTITUD ADAPTATIVA/

LETICIA INÉS LAROTONDA; BELÉN BURDIGNON; DIEGO COMERCI; ALFONSO SOLER BISTUE

Buenos Aires

Congreso; XV Congreso Argentino de Microbiología (CAM) - 2019; 2019

Asociación Argentina de Microbiología

Growth rate (GR) is a key parameter of bacterial physiology widely varying among microorganisms. However, the genetic basis of GR is still unclear. In fast-growing bacteria, the genes encoding ribosomal protein genes (RP) and RNA polymerase (RNAP) are close to the origin of replication (oriC). During exponential growth, fast growers perform multi-fork replication. As a consequence, genes near oriC benefit of higher dosage during exponential growth. Therefore, such positional bias can be a strategy to maximize the expression of transcription and translation machineries. Since most of these observations come from bioinformatic studies. We aimed at experimentally testing these correlations in fast-growing bacteria. We used Vibrio cholerae as model fast-growing bacterium. Its genome can be widely modified by natural transformation coupled to recombineering techniques based on lambdoid phage recombination tools. As model loci we studied S10-spc-α (S10) wich codes most of RP and rpoBC wich encodes the core of the sole bacterial RNAP. Using the aforementioned tools we altered the genomic location of these strategic loci. Previous evidence attributed more predictive power of GR to RNAP position. We relocated these loci at increasing distances of the oriC. Our results show that the relocation of both loci far for the oriC led to lower GR and fitness. The relocation of S10 caused a stronger effect. Close relocation displayed no phenotype indicating that relocation process perse was not detrimental. Trough time-lapse microscopy we check that differences in GR are due to the relocation of the locus and not to viability loss or death of subpopulation. Also, the parameter of UFC/OD was invariable between the strains suggesting that the relocalization of the locus doesn´t alter the viability of the cell. In future works, we will seek for the relocation of both loci, S10 and rpoBC, simultaneously far from the OriC in order to generate a strain of Vibrio cholera with the lowest GR as possible, wich could be use as a potential vaccine for Colera.