Abstract
To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.
Highlights
About 80% of the functions they encode fall in a few large categories; namely, information processing, cell envelope, shape, division, and energetics. These observations lead to a view of a rather simple bacterial cell, consisting of a compartment, formed by a membrane and a wall, enclosing the elements necessary to synthesize proteins that carry out reactions required for (i) the duplication and inheritance of the genetic information; (ii) the division of the compartment; and (iii) the provision of energy
Over 80% of essential B. subtilis gene homologues are present in all bacteria with genomes above Ϸ3 Mb, and 57% are found even in bacteria with the smallest genomes
A minimal essential gene set could be significantly smaller than the one present in bacteria with genomes larger than Ϸ3 Mb
Summary
To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. An experimental approach involving high-density transposon mutagenesis of the H. influenzae genome led to a much higher estimate of Ϸ670 putative essential genes [3], whereas transposon mutagenesis of two mycoplasma species led to an estimate of 265–360 essential genes [4] Another experimental approach using antisense RNA to inhibit gene expression led to the identification of some 150 essential genes in Staphylococcus aureus [5]. To obtain an independent and possibly more reliable estimate of a minimal protein-encoding gene set for bacteria, we systematically inactivated Bacillus subtilis genes. Because the essentiality of a gene depends on the conditions under which the organism is propagated, we used an environment likely to be optimal for B. subtilis and carried out inactivation on a Downloaded by guest on October 5, 2020
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
