Replication-dependent gene dosage of the major ribosomal protein locus regulates growth rate of Vibrio cholerae.

SOLER BISTUE, ALFONSO; SEBASTIAN AGUILAR-PIERLE; DIDIER MAZEL

Maastrich

Congreso; FEMS 6th Congress of European Microbiologists; 2015

Federation of European Microbiological Societies

Background:The effects of geneorder within the bacterial chromosome on cell physiology are poorly understood.In silico approaches have showed thatribosomal protein genes locate near the replication origin (oriC) in fast-growing bacteria,suggesting that such a positional bias is an evolutionarily conservedgrowth-optimization strategy. Vibrio cholerae, a bi-chromosomal fast-growing pathogen is awell-characterized model organism to experimentally tackle this hypothesis. TheS10-spc-α locus (S10) encodes half ofthe ribosomal protein genes and is conserved along all life forms.Objectives:To relocate S10 to different positions along the genome and measure putativephysiological effects.Methods:We used novelrecombineering tools to create a set of isogenic strains in which S10 wassystematically relocated to alternative genomic positions. Their DNA and RNA wasanalyzed using NGS. Conclusions:We show that S10relative distance to the oriC tightlycorrelates with a reduction of its dosage, mRNA abundance and growth rate. Thisis accompanied by a significant reduction in host-invasion capacity of Drosophilamelanogaster. Strains bearing two S10 copies far from oriC rescueboth phenotypes demonstrating that replication-dependent gene-dosage reductionis the main mechanism behind these alterations. Deep sequencing analyses showsthat i) the whole oriC region is lesstranscribed in the most affected derivatives and ii) Gene Set Enrichment Analysesreveal ?translation? as the most altered pathway in such derivatives. S10 positioningconnects genome structure to cell physiology in V. cholerae. We showthat genomic positioning of genes involved in the flux of genetic informationconditions global growth and hence bacterial physiology and evolution.