bioRxiv preprint doi: https://doi.org/10.1101/2020.08.12.247981; this version posted August 12, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Construction of a complete set of Neisseria meningitidis defined mutants – the 2 NeMeSys collection – and its use for the phenotypic profiling of the genome of 3 an important human pathogen 4 5 Alastair Muir1, Ishwori Gurung1, Ana Cehovin1, Adelme Bazin2, David Vallenet2, 6 Vladimir Pelicic1,* 7 8 1MRC Centre for Molecular Bacteriology and Infection, Imperial College London, 9 London, United Kingdom 10 11 2LABGeM, Génomique Métabolique, CEA, Genoscope, Institut François Jacob, 12 Université d’Evry, Université Paris-Saclay, CNRS, Evry, France 13 14 *Corresponding author 15 E-mail:
[email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.08.12.247981; this version posted August 12, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 16 Abstract 17 One of the most important challenges in biology is to determine the function of 18 millions of genes of unknown function. Even in model bacterial species, there is a 19 sizeable proportion of such genes, which has important theoretical and practical 20 consequences. Here, we constructed a complete collection of defined mutants – 21 named NeMeSys – in the important human pathogen Neisseria meningitidis, 22 consisting of individual mutants in 1,584 non-essential genes. This effort identified 23 391 essential meningococcal genes – highly conserved in other bacteria – leading to 24 a full panorama of the minimal genome in this species, associated with just four 25 underlying basic biological functions: 1) expression of genome information, 2) 26 preservation of genome information, 3) cell membrane structure/function, and 4) 27 cytosolic metabolism.