Biology Reference
In-Depth Information
16
Tagging of HIV with Green Fluorescent
Protein
Nadya I. Tarasova
Molecular Aspects of Drug Design Section, National Cancer Institute,
Frederick Cancer Research and Development Center, Frederick, Maryland
INTRODUCTION
Starting in 1995, the use of the green ¯uorescent protein (GFP) in retroviral
research has been constantly growing. GFP is now used for the detection of
infected cells, studying viral tra½cking, and characterization of viral proteins
functions, and as a reporter in the development of the gene therapy approaches.
GFP has been used as a label in studies of human immunode®ciency virus
( HIV ) in at least four methodologically di¨erent ways. Two approaches were
used for the production of ¯uorescent virions, labeling in cis and in trans. For
labeling in cis, GFP is incorporated into the viral genome. The recombinant
viruses express GFP during replication, and, thus, infected cells can be identi-
®ed easily with ¯uorescence detection methods. Labeling of viral particles in
trans takes place during self-assembly of the virions. One of the viral proteins is
coexpressed as a fusion with GFP simultaneously with the virus and is sponta-
neously and very speci®cally incorporated into the viral particles. The resulting
¯uorescent virions allow for direct observation of one cycle of virus infection,
but they do not replicate as ¯uorescent particles. GFP is also widely used as
a reporter gene for ¯uorescence-based detection of retroviral infection and for
measurement of gene transfer with HIV-derived retroviral vectors. Fusion of
many HIV-1 proteins to GFP was used for studying the function and tra½cking
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