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Sherwood R. Casjens

Sherwood R. Casjens, PhD

Languages spoken: English

Academic Information

Departments Emeritus - Pathology


Academic Office Information

Research Interests

  • Genetic control of the assembly of virus particles
  • Modular evolution of bacteriophage genomes
  • Genome structure and replication of the Lyme disease causing bacteria, Borrelia burgdorferi

Research Statement

The Casjens laboratory is studying three rather different areas: (1) the genetic control of the assembly of virus particles, (2) modular evolution of bacteriophage genomes, and (3) genome structure and replication of the Lyme disease causing bacteria, Borrelia burgdorferi and its relationship to other bacterial genomes.

Our work on virus assembly is concentrated on genetic and biochemical analysis of the proteins that are necessary for packaging a DNA molecule into bacteriophage P22 virions. One of these is involved in recognizing the proper DNA for packaging, two build the virus particle itself, and two are required for DNA to enter the particles.

We have also been involved in the sequencing an characterization of the genomes of several tailed-bacteriophages - P22, Sf6, L, Mu, N15, ES18, KO2, 9NA, Det7 and SPO1. These genomes are a rich source of information on bacteriophage diversity as well as ideas for how bacteriophages evolve and interact with their hosts.

Our Borrelia burgdorferi work has shown that these bacteria are unique in that, unlike other bacteria, they have a linear chromosome with covalently closed hairpin ends and they carry a very large number of linear and circular plasmid DNAs. Our current work is directed toward understanding the complete gene pool (pan-genome) available to this pathogen and toward understanding the detailed structure, replication and diversity of the linear chromosome and plasmid ends. We also use this information to understand the genetic diversity and evolution of this species.

Education History

Postdoctoral Fellowship Massachusetts Institute of Technology
Postdoctoral Fellow
Stanford University
Graduate Training Michigan State University
Michigan State University

Selected Publications

Journal Article

  1. Grose JH, Casjens SR (2014). Understanding the enormous diversity of bacteriophages: The tailed phages that infect the bacterial family Enterobacteriaceae. Virology, 468-470C, 421-443.
  2. Parent KN, Tang J, Cardone G, Gilcrease EB, Janssen ME, Olson NH, Casjens SR, Baker TS (2014). Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain. Virology, 464-465, 55-66.
  3. Parent KN, Erb ML, Cardone G, Nguyen K, Gilcrease EB, Porcek NB, Pogliano J, Baker TS, Casjens SR (2014). OmpA and OmpC are critical host factors for bacteriophage Sf6 entry in Shigella. Mol Microbiol, 92(1), 47-60.
  4. Bearson BL, Allen HK, Brunelle BW, Lee IS, Casjens SR, Stanton TB (2014). The agricultural antibiotic carbadox induces phage-mediated gene transfer in Salmonella. Front Microbiol, 5, 52.
  5. Leavitt JC, Gilcrease EB, Wilson K, Casjens SR (2013). Function and horizontal transfer of the small terminase subunit of the tailed bacteriophage Sf6 DNA packaging nanomotor. Virology, 440(2), 117-33.
  6. Mongodin EF, Casjens SR, Bruno JF, Xu Y, Drabek EF, Riley DR, Cantarel BL, Pagan PE, Hernandez YA, Vargas LC, Dunn JJ, Schutzer SE, Fraser CM, Qiu WG, Luft BJ (2013). Inter- and intra-specific pan-genomes of Borrelia burgdorferi sensu lato: genome stability and adaptive radiation. BMC Genomics, 14, 693.
  7. Leavitt JC, Gogokhia L, Gilcrease EB, Bhardwaj A, Cingolani G, Casjens SR (2013). The tip of the tail needle affects the rate of DNA delivery by bacteriophage P22. PLoS One, 8(8), e70936.
  8. Padilla-Meier GP, Gilcrease EB, Weigele PR, Cortines JR, Siegel M, Leavitt JC, Teschke CM, Casjens SR (2012). Unraveling the role of the C-terminal helix turn helix of the coat-binding domain of bacteriophage P22 scaffolding protein. J Biol Chem, 287(40), 33766-80.
  9. Huang WM, DaGloria J, Fox H, Ruan Q, Tillou J, Shi K, Aihara H, Aron J, Casjens S (2012). Linear chromosome-generating system of Agrobacterium tumefaciens C58: protelomerase generates and protects hairpin ends. J Biol Chem, 287(30), 25551-63.
  10. Parent KN, Gilcrease EB, Casjens SR, Baker TS (2012). Structural evolution of the P22-like phages: comparison of Sf6 and P22 procapsid and virion architectures. Virology, 427(2), 177-88.
  11. Casjens SR, Mongodin EF, Qiu WG, Luft BJ, Schutzer SE, Gilcrease EB, Huang WM, Vujadinovic M, Aron JK, Vargas LC, Freeman S, Radune D, Weidman JF, Dimitrov GI, Khouri HM, Sosa JE, Halpin RA, Dunn JJ, Fraser CM (2012). Genome stability of Lyme disease spirochetes: comparative genomics of Borrelia burgdorferi plasmids. PLoS One, 7(3), e33280.


  1. Casjens SR (2011). The DNA-packaging nanomotor of tailed bacteriophages. [Review]. Nat Rev Microbiol, 9(9), 647-57.

Book Chapter

  1. Casjens S and Molineux I (2012). Short non-contractile tail machines: adsorption and DNA delivery by the podoviruses. In Rossmann, M., and Rao, V (Eds.), Adv. Exp. Med. Biol. (Viral molecular machines) (726, pp. 143-179).
  2. Casjens S (2011). A Plethora of Putative Phages and Prophages. In Maloy S, Hughes K, Casadesús J (Eds.), The lure of bacterial genetics: a tribute to John Roth (pp. 291-306).
  3. Casjens S, Eggers C, Schwatrz I (2010). Borrelia Genomics: Chromosome, Plasmids, Bacteriophages and Genetic Variation. In Radolf JD, Samuels DS (Eds.), Borrelia: Molecular biology, host interaction and pathogenesis (pp. 26-52).


  1. Casjens SR, co-inventor (1998). Borrelia burgdorferi polynucleotides and sequences U-2368.

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