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Piya D, Nolan N, Moore ML, Ramirez Hernandez LA, Cress BF, Young R, Arkin AP, Mutalik VK. Systematic and scalable genome-wide essentiality mapping to identify nonessential genes in phages. PLoS Biol 2023; 21:e3002416. [PMID: 38048319 PMCID: PMC10695390 DOI: 10.1371/journal.pbio.3002416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 11/02/2023] [Indexed: 12/06/2023] Open
Abstract
Phages are one of the key ecological drivers of microbial community dynamics, function, and evolution. Despite their importance in bacterial ecology and evolutionary processes, phage genes are poorly characterized, hampering their usage in a variety of biotechnological applications. Methods to characterize such genes, even those critical to the phage life cycle, are labor intensive and are generally phage specific. Here, we develop a systematic gene essentiality mapping method scalable to new phage-host combinations that facilitate the identification of nonessential genes. As a proof of concept, we use an arrayed genome-wide CRISPR interference (CRISPRi) assay to map gene essentiality landscape in the canonical coliphages λ and P1. Results from a single panel of CRISPRi probes largely recapitulate the essential gene roster determined from decades of genetic analysis for lambda and provide new insights into essential and nonessential loci in P1. We present evidence of how CRISPRi polarity can lead to false positive gene essentiality assignments and recommend caution towards interpreting CRISPRi data on gene essentiality when applied to less studied phages. Finally, we show that we can engineer phages by inserting DNA barcodes into newly identified inessential regions, which will empower processes of identification, quantification, and tracking of phages in diverse applications.
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Affiliation(s)
- Denish Piya
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California, United States of America
| | - Nicholas Nolan
- Department of Bioengineering, University of California-Berkeley, Berkeley, California, United States of America
| | - Madeline L. Moore
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Luis A. Ramirez Hernandez
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Brady F. Cress
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, California, United States of America
| | - Ry Young
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, Texas, United States of America
| | - Adam P. Arkin
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California-Berkeley, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Vivek K. Mutalik
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
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Łobocka MB, Rose DJ, Plunkett G, Rusin M, Samojedny A, Lehnherr H, Yarmolinsky MB, Blattner FR. Genome of bacteriophage P1. J Bacteriol 2004; 186:7032-68. [PMID: 15489417 PMCID: PMC523184 DOI: 10.1128/jb.186.21.7032-7068.2004] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Accepted: 07/09/2004] [Indexed: 11/20/2022] Open
Abstract
P1 is a bacteriophage of Escherichia coli and other enteric bacteria. It lysogenizes its hosts as a circular, low-copy-number plasmid. We have determined the complete nucleotide sequences of two strains of a P1 thermoinducible mutant, P1 c1-100. The P1 genome (93,601 bp) contains at least 117 genes, of which almost two-thirds had not been sequenced previously and 49 have no homologs in other organisms. Protein-coding genes occupy 92% of the genome and are organized in 45 operons, of which four are decisive for the choice between lysis and lysogeny. Four others ensure plasmid maintenance. The majority of the remaining 37 operons are involved in lytic development. Seventeen operons are transcribed from sigma(70) promoters directly controlled by the master phage repressor C1. Late operons are transcribed from promoters recognized by the E. coli RNA polymerase holoenzyme in the presence of the Lpa protein, the product of a C1-controlled P1 gene. Three species of P1-encoded tRNAs provide differential controls of translation, and a P1-encoded DNA methyltransferase with putative bifunctionality influences transcription, replication, and DNA packaging. The genome is particularly rich in Chi recombinogenic sites. The base content and distribution in P1 DNA indicate that replication of P1 from its plasmid origin had more impact on the base compositional asymmetries of the P1 genome than replication from the lytic origin of replication.
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Affiliation(s)
- Małgorzata B Łobocka
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Ul. Pawinskiego 5A, 02-106 Warsaw, Poland.
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Schofield DA, Westwater C, Dolan JW, Schmidt MG, Norris JS. Controlled expression in Klebsiella pneumoniae and Shigella flexneri using a bacteriophage P1-derived C1-regulated promoter system. J Bacteriol 2001; 183:6947-50. [PMID: 11698385 PMCID: PMC95537 DOI: 10.1128/jb.183.23.6947-6950.2001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The utility of promoters regulated by the bacteriophage P1 temperature-sensitive C1 repressor was examined in Shigella flexneri and Klebsiella pneumoniae. Promoters carrying C1 operator sites driving LacZ expression had induction/repression ratios of up to 240-fold in S. flexneri and up to 50-fold in K. pneumoniae. The promoters exhibited remarkably low basal expression, demonstrated modulation by temperature, and showed rapid induction. This system will provide a new opportunity for controlled gene expression in enteric gram-negative bacteria.
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Affiliation(s)
- D A Schofield
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29403, USA.
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