tor of early T cell activation genes. To test this hy- 
pothesis, the laboratory has prepared transgenic 
mice with three copies of the 28 bp NFAT-binding 
site directing transcription of several indicator 
genes. In four of four transgenic lines in which the 
NFAT site was present, properly initiated transcrip- 
tion of the indicator gene was restricted to acti- 
vated lymphocytes, whereas in transgenic lines 
without the NFAT site, transcription was either ab- 
PUBLICATIONS 
sent or present in inappropriate tissues. These re- 
sults indicate that the NFAT protein accounts at 
least partly for the remarkable tissue specificity of 
IL-2 expression. In the coming year. Dr. Crabtree 
and his colleagues will attempt to purify and char- 
acterize the NFAT protein. 
Dr. Crabtree is also Associate Professor of Pathol- 
ogy at Stanford University School of Medicine. 
Articles 
Courtois, G., Baumhueter, S., and Crabtree, G.R. 1988. Purified hepatocyte nuclear factor 1 interacts with a 
family of hepatocyte-specific promoters. Proc Natl Acad Sci USA 85:7937-7941. 
Crabtree, G.R. 1989. Contingent genetic regulatory events in T lymphocyte activation. Science 243:355-361. 
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