Interleukin-3 expression by activated T cells involves an inducible, T-
cell-specific factor and an octamer binding protein
K Davies, EC TePas, DG Nathan and B Mathey-Prevot
Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
02115.
Interleukin-3 (IL-3) is exclusively expressed by activated T and natural
killer cells, a function that is tightly controlled both in a
lineage-specific and in a stimulation-dependent manner. We have
investigated the protein binding characteristics and functional importance
of the ACT-1-activating region of the IL-3 promoter. This region binds an
inducible, T-cell-specific factor over its 5' end, a site that is necessary
for the expression of IL-3 in the absence of other upstream elements. Over
its 3' end, it binds a factor that is ubiquitously and constitutively
expressed. This factor is Oct-1 or an immunologically related
octamer-binding protein, and it plays a role in coordinating the activity
of several regulatory elements. These characteristics make the ACT-1 site
analogous to the activating ARRE-1 site in the IL-2 promoter. Furthermore,
and despite a lack of sequence homology, the promoters of IL-3 and IL-2
share an organizational pattern of regulatory elements that is likely to be
important for the T- cell-specific expression of these genes.
Volume 81,
Issue 4,
pp. 928-934,
02/15/1993
Copyright © 1993 by The American Society of Hematology
