- 1970: A.B., Harvard College
- 1974: M.D., University of California, San Francisco
The Garcea laboratory studies the structure and assembly of small DNA viruses, with emphasis on polyoma and papillomaviruses. Current interests are 1) the mechanism of mitogenic signal transduction initiated by the interaction of viral capsid proteins with cell surface gangliosides, and 2) the sites of virion assembly in the nucleus and the cellular proteins that mediate genome packaging. In addition, structural studies of human papillomavirus (HPV) have led to translational research concerning the development of next generation HPV vaccines using capsid subunits (capsomeres) that are purified after bacterial expression of the L1 viral coat protein. The laboratory therefore offers an environment for both basic and translational research, with opportunities for graduate students, post-doctoral fellows, and clinical fellows.
Research Interests : Structure and assembly of small DNA viruses (polyoma and papilloma); development of low cost vaccines for under-resourced areas of the world.
Research Profile : The laboratory studies the cell biology of small DNA virus assembly with emphasis on:
1) characterizing sites of viral assembly in the cell nucleus.
2) defining mitogenic signals resulting from the initial contact of the virus capsid with cell surface gangliosides.
We have found that cell chaperone proteins (hsc70 family) bind the polyomavirus capsid proteins immediately post translation and appear to accompany the viral proteins as they are transported into the nucleus. We have recently recapitulated chaperone-mediated capsid assembly in vitro using recombinant capsid proteins, hsc70/hsp40, and ATP.
In polyomavirus infected cells, virion assembly appears to take place at distinct "foci" within the nucleus termed PML-nuclear bodies. We are investigating the role of PML-NBs in polyomavirus assembly in mouse cells, and using cryo-EM to image these "virus factories." Virus assembly at these foci also appears to recruit cell DNA damage response proteins, which are essential for virus replication.
The polyomavirus capsid protein VP1 binds specific cell surface ganglioside molecules as a first step in infection. The engagement of these molecules results in a mitogenic signal that facilitates subsequent viral genomic replication. Each species of polyomavirus has a different ganglioside specificity, making VP1 an excellent reagent to study ganglioside signaling. These studies are enabled by the use of ganglioside-deficient cell lines that can be reconstituted with the ganglioside of choice.
In addition to basic cell biology of virus infection, the laboratory is also pursuing translational research concerning the development of new human papillomavirus (HPV) vaccines. Infection with "high-risk" human papillomaviruses is associated with the subsequent development of cervical cancer. However, current vaccines are costly and thus unavailable to women in resource-poor areas of the world. We have found that the subunits (capsomeres) of the virus capsid are equivalent to the entire capsid in generating protective immunity in model animal systems. Capsomeres can be purified after expression in bacteria, and thus potentially offer a low cost alternative to the current vaccines. Capsomeres are now being optimized for GMP production, and human trials will be pursued in collaboration with industrial partners under the auspices of an NCI SPORE grant in Cervical Cancer.
Awards and Honors
1966 National Merit Scholar
1967-1970 Harvard College Scholar
1976-1978 Muscular Dystrophy Postdoctoral Fellow
1978-1981 Leukemia Society of America Postdoctoral Fellow
1987-1989 American Cancer Society Junior Faculty Award
1989 American Society for Clinical Investigation
1993 Society for Pediatric Research
2006 UCDHSC Inventor of the Year
2006-08 Chair-Elect/Chair, American Society of Microbiology, Division S (DNA Viruses)
2012 Fellow, American Academy of Microbiology