Localization of the inducible enhancer in the mouse interleukin-5 gene that
is responsive to T-cell receptor stimulation
PF Bourke, BH van Leeuwen, HD Campbell and IG Young
Division of Biochemistry and Molecular Biology, John Curtin School of
Medical Research, Australian National University, Canberra.
Transcriptional regulation of the interleukin-5 (IL-5) gene in T
lymphocytes appears to be of central importance in the control of the
eosinophilia characteristic of allergic responses and certain parasite
infections. Previous studies of IL-5 gene regulation have been hampered by
the lack of a transfection assay, which detects the antigen- responsive
enhancer in the IL-5 promoter. Here we show that stable transfection of the
Th2 clone D10.G4.1 and the T lymphoma EL4.23 with chloramphenicol
acetyltransferase reporter gene constructs carrying the region to -3859
gives inducible expression with the known regulatory characteristics of the
endogenous IL-5 gene. To facilitate detailed analysis of the promoter
region, 3.9 kb of DNA sequence immediately up stream of the start of
transcription was determined and the minimum upstream region required for
inducible expression was further localized, by stable transfection studies
in EL4.23 cells, to the region up to -1016. A CTF/NF1 site in the upstream
enhancer at -940 to - 928 was shown to be required for regulated inducible
expression. Mutation of this sequence motif abolished inducibility and also
prevented binding of the sequence to a nuclear protein(s). A TCATTT-
containing element in the proximal promoter region was also demonstrated to
be essential for inducible expression of the IL-5 gene, similar to the role
of this conserved element in the transcriptional regulation of the
granulocyte-macrophage colony-stimulating factor (GM- CSF) and IL-4 genes.
Volume 85,
Issue 8,
pp. 2069-2077,
04/15/1995
Copyright © 1995 by The American Society of Hematology
