iv)
Identification of a novel interleukin-6 response element containing
an Ets-binding site and a CRE-like site in the junB promoter.
Nakajima-K; Kusafuka-T; Takeda-T; Fujitani-Y; Nakae-K; Hirano-T,
Mol-Cell-Biol. 1993 May; 13(5): 3027-41iv)
Identification of a novel interleukin-6 response element containing
an Ets-binding site and a CRE-like site in the junB promoter.
Nakajima-K; Kusafuka-T; Takeda-T; Fujitani-Y; Nakae-K; Hirano-T,
Mol-Cell-Biol. 1993 May; 13(5): 3027-41
Interleukin-6 (IL-6) activation of the immediate-early gene junB has
been shown to require both a tyrosine kinase and an unknown
1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7)-sensitive pathway.
Here we report the identification and characterization of an IL-6
immediate-early response element in the junB promoter (designated
JRE-IL6) in HepG2 cells. The JRE-IL6 element, located at -149 to
-124, contains two DNA motifs, an Ets-binding site (EBS) (CAGGAAGC)
and a CRE-like site (TGACGCGA). Functional studies using variously
mutated JRE-IL6 elements showed that both motifs were necessary and
sufficient for IL-6 response of the promoter. The EBS of the JRE-IL6
element (JEBS) appears to bind a protein in the Ets family or a
related protein which could also form a major complex with the EBSs
of the murine sarcoma virus long terminal repeat or human T-cell
leukemia virus type 1 long terminal repeat. The CRE-like site appears
to weakly bind multiple CREB-ATF family proteins. Despite the
similarity in the structure between the JRE-IL6 element and the
polyomavirus enhancer PyPEA3, composed of an EBS and an AP1-binding
site and known to be activated by a variety of oncogene signals,
JRE-IL6 could not be activated by activated Ha-Ras, Raf-1, or
12-O-tetradecanoylphorbol-13-acetate. We show that IL-6 activates
JRE-IL6 through an H7-sensitive pathway that does not involve protein
kinase C, cyclic AMP-dependent kinase, Ca(2+)- or
calmodulin-dependent kinases, Ras, Raf-1, or NF-IL6 (C/EBP beta). The
combination of JEBS and the CRE-like site appears to form the basis
for the selective and efficient response of JRE-IL6 to IL-6 signals,
but not to signals generated by activated Ha-Ras, Raf-1, or protein
kinase C.
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