Robert L. Garcea, M.D.

Professor of Pediatrics
Professor of Cell and Structural Biology
Professor of Microbiology

Department of Pediatrics
University of Colorado at Denver and Health Sciences Center
RC1 North Tower, Room 4100
P.O. Box 6511, MS 8302
Aurora, Colorado 80045

Phone: 303.724-4000
Bob.Garcea@uchsc.edu

EDUCATION/EXPERIENCE

HONORS AND AWARDS

PROFESSIONAL ACTIVITIES

Research Interests:

Our understanding of how large macromolecular structures are assembled has been greatly advanced in recent years by the crystallization of viruses. In particular, the papovaviruses (e.g. SV40, human papillomaviruses) represent some of the largest biological structures yet determined at atomic resolution. Polyoma is a dsDNA virus comprised of 72 pentamers (capsomeres) of the VP1 coat protein, arranged in a T=7 icosahedral shell (capsid; 500Å in diameter) around a viral minichromosome. Two minor coat proteins, VP2 and VP3, appear to serve as bridges between the viral minichromosome and the capsid. VP1, purified after expression in E. coli, self- assembles in vitro into capsid-like structures upon the addition of calcium. This property has been used as an assay in the structure-function analysis of capsid assembly by introducing mutations in domains of VP1 (identified in the 3.8Å resolution crystal structure of the virus) involved in capsid formation.

One goal is to assemble an infectious virus in vitro from recombinant proteins. The papillomaviruses are organized in a similar mannner. Recently we determined (in collaboration with Xiaojiang Chen and Steve Harrison) the atomic structure of an L1 (analogous to VP1) coat protein of a human papillomavirus, purified after recombinant expression in E. coli. We are now studying 1) the domains of L1 that contribute to capsid size determination, 2) the complex of L1 with an Fab fragment of a virus neutralizing antibody, 3) the structures of related papillomavirus L1 proteins to compare surface features that may reveal common and disparate functional relationships (such as neutralizing epitopes and receptor binding sites).

Because infection with certain "high-risk" human papillomaviruses is associated with the subsequent development of cervical cancer, these structural studies are now also being applied to developing new vaccine reagents to prevent papillomavirus infection.

Selected Publications

• Garcea RL, Imperiale MJ. Simian virus 40 infection of humans.
  J Virol. 2003 May;77(9):5039-45. [Abstract]
  
  
• Finnen RL, Erickson KD, Chen XS, Garcea RL. Interactions between Papillomavirus L1 and L2 Capsid Proteins. J Virol. 2003 Apr;77(8):4818-26. [Abstract]
  
  
• Ohlschlager P, Osen W, Dell K, Faath S, Garcea RL, Jochmus I, Muller M, Pawlita M, Schafer K, Sehr P, Staib C, Sutter G, Gissmann L. Human papillomavirus type 16 l1 capsomeres induce l1-specific cytotoxic T lymphocytes and tumor regression in C57BL/6 mice.
  J Virol. 2003 Apr;77(8):4635-45. [Abstract]
  
  
• Garcea RL. SV40: A human pathogen? Dis Markers. 2001;17(3):149-51. Review. [Abstract]
  
  
• Malkin D, Chilton-MacNeill S, Meister LA, Sexsmith E, Diller L, Garcea RL. Tissue-specific expression of SV40 in tumors associated with the Li-Fraumeni syndrome. Oncogene. 2001 Jul 27;20(33):4441-9. [Abstract]
  
  
• Yuan H, Estes PA, Chen Y, Newsome J, Olcese VA, Garcea RL, Schlegel R. Immunization with a pentameric L1 fusion protein protects against papillomavirus infection. J Virol. 2001 Sep;75(17):7848-53. [Abstract]
  
  
• Chen XS, Casini G, Harrison SC, Garcea RL. Papillomavirus capsid protein expression in Escherichia coli: purification and assembly of HPV11 and HPV16 L1. J Mol Biol. 2001 Mar 16;307(1):173-82. [Abstract]
  
  
• Lednicky JA, Garcea RL. Detection of SV40 DNA sequences in human tissue. Methods Mol Biol. 2001;165:257-67.
  
  

• Szomolanyi-Tsuda, E., Brien, J.D., Dorgan, J.E., Garcea, R.L., Woodland, R.T., and Welsh, R.M. Antiviral T cell-independent type 2 antibody responses induced in vivo in the absence of T and NK cells. Virology 2001; 280:160-168. [Abstract]

• Chen, X., Casini, G. Harrison, S.C., and Garcea, R.L. Papillomavirus capsid protein expression in Escherichia coli: Purification and assembly of HPV11 and HPV16 L1 J. Mol. Bio. 2001: 307: 173-182. [Absract]

• Malkin, D., Chilton-MacNeill, S., Meister, L.A., Sexsmith, E., Diller, L., and Garcea, R.L. Tissue-specific expression of SV40 virus and mechanisms of loss of heterozygosity of p53 in a child with Li-Fraumeni Syndrome. Oncogene 2001; 20: 4441-4449.[Abstract]

• Yuan, H., Estes, P.A., Chen, Y., Newsome, J., Olcese, V.A., Garcea, R.L., and Schlegel, R. Immunization with a pentameric L1 fusion protein protects against papillomavirus infection. J. Virol. 2001; 75: 7848-7853.
  [Abstract]

• Schwartz, R., Garcea, R.L., and Berger, B. "Local Rules" theory applied to polyomavirus polymorphic capsid assemblies. Virology 2000; 268:461-470. [Abstract]

• Chen, X., Garcea, R.L., Casini, G., Goldberg, I., and Harrison, S.C. Structure of small virus-like particles assembled from the L1 protein of human papillomavirus 16. Mol. Cell 2000; 5:557-567. [Abstract]

• Szomolanyi-Tsuda, E., Brien, J.D., Dorgan, J.E., Welsh, R.M., and Garcea, R.L. The role of CD40-CD154 interaction in antiviral T cell-independent IgG responses. J. Immunol. 2000; 164:5877-82. [Abstract]

• Szomolanyi-Tsuda, E., Le, Q.P., Garcea, R.L., and Welsh, R.M. T cell-independent immunoglobulin G responses in vivo are elicited by live-virus infection, but not by immunization with viral proteins or virus-like particles. J. Virol. 1998; 72:6665-6670. [Abstract]

• Rose, R.C., White, W., Li, M., Suzich, J., Lane, C., and Garcea, R.L. Human papillomavirus type 11 (HPV-11) recombinant L1 capsomeres induce virus-neutralizing antibodies. J. Virol. 1998; 72:6151-6154. [Abstract]

• Li. M., Beard, P., Estes, P.A., Lyon, M.K., and Garcea, R.L. Intercapsomeric disulfide bonds in papillomavirus assembly and disassembly. J. Virol. 1998; 72:2160-2167. [Abstract]

• Li, M., Cripe, T. P., Estes, P. A., Lyon, M. K., Rose, R. C., and Garcea, R. L. Expression of the human papillomavirus type 11 L1 capsid protein in Escherichia coli: Characterization of protein domains involved in DNA binding and capsid assembly. J. Virol. 1997; 71:2988-2995. [Abstract]