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STAT3 is required for the gp130-mediated full activation of the c-myc gene.

Kiuchi N, Nakajima K, Ichiba M, Fukada T, Narimatsu M, Mizuno K, Hibi M, Hirano T - J. Exp. Med. (1999)

Bottom Line: STAT3 does so most likely by binding to cis-regulatory region(s) of the c-myc gene.We show that STAT3 binds to a region overlapping with the E2F site in the c-myc promoter and this site is critical for the c-myc gene promoter- driven transcriptional activation by IL-6 or gp130 signals.This is the first identification of the linkage between a member of the STAT family and the c-myc gene activation, and also explains how the IL-6 family of cytokines is capable of inducing the expression of the c-myc gene.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Suita, Osaka 565-0871, Japan.

ABSTRACT
The signal transducers and activators of transcription (STAT) family members have been implicated in regulating the growth, differentiation, and death of normal and transformed cells in response to either extracellular stimuli, including cytokines and growth factors, or intracellular tyrosine kinases. c-myc expression is coordinately regulated by multiple signals in these diverse cellular responses. We show that STAT3 mostly mediates the rapid activation of the c-myc gene upon stimulation of the interleukin (IL)-6 receptor or gp130, a signal transducing subunit of the receptor complexes for the IL-6 cytokine family. STAT3 does so most likely by binding to cis-regulatory region(s) of the c-myc gene. We show that STAT3 binds to a region overlapping with the E2F site in the c-myc promoter and this site is critical for the c-myc gene promoter- driven transcriptional activation by IL-6 or gp130 signals. This is the first identification of the linkage between a member of the STAT family and the c-myc gene activation, and also explains how the IL-6 family of cytokines is capable of inducing the expression of the c-myc gene.

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Induction of c-myc mRNA expression via gp130 signaling in  BAF-G277 cells. (A) Northern blot analysis for c-myc mRNA expression  in G-CSF–stimulated BAF/B03 transfectants expressing a chimeric receptor consisting of the G-CSFR extracellular domain and the transmembrane and cytoplasmic domains of gp130, including the full-length, 277  amino acid–long cytoplasmic domain (BAF-G277). Total RNAs were  extracted from BAF-G277 cells (lanes 1–7) and parental BAF/B03 cells  (lanes 8–10) which had been deprived of IL-3 for 12 h and then stimulated with 100 ng/ml G-CSF for the indicated periods of time and subjected to Northern blot analysis for detection of c-myc mRNA (top) and  CHO-B mRNA (bottom), the latter being controls for the amounts of  loaded RNA. (B) Kinetic changes in the c-myc mRNA levels. Values for  c-myc mRNA levels were normalized to those for the corresponding  CHO-B mRNA levels and were plotted. Means ± SD of data from three  independent experiments are shown. (C) c-myc mRNA induction in the  presence of an inhibitor for protein synthesis. Total RNAs were extracted  from BAF-G277 cells, which had been deprived of IL-3 for 12 h and  then stimulated with 0 (lanes 1 and 3) or 100 ng/ml of G-CSF for 1 h  (lanes 2 and 4) in the absence (lanes 1 and 2) or presence (lanes 3 and 4) of  30-min pretreatment of cells with 10 μg/ml of cycloheximide, and were  subjected to Northern blot analysis for c-myc and CHO-B mRNA expression as in A.
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Figure 1: Induction of c-myc mRNA expression via gp130 signaling in BAF-G277 cells. (A) Northern blot analysis for c-myc mRNA expression in G-CSF–stimulated BAF/B03 transfectants expressing a chimeric receptor consisting of the G-CSFR extracellular domain and the transmembrane and cytoplasmic domains of gp130, including the full-length, 277 amino acid–long cytoplasmic domain (BAF-G277). Total RNAs were extracted from BAF-G277 cells (lanes 1–7) and parental BAF/B03 cells (lanes 8–10) which had been deprived of IL-3 for 12 h and then stimulated with 100 ng/ml G-CSF for the indicated periods of time and subjected to Northern blot analysis for detection of c-myc mRNA (top) and CHO-B mRNA (bottom), the latter being controls for the amounts of loaded RNA. (B) Kinetic changes in the c-myc mRNA levels. Values for c-myc mRNA levels were normalized to those for the corresponding CHO-B mRNA levels and were plotted. Means ± SD of data from three independent experiments are shown. (C) c-myc mRNA induction in the presence of an inhibitor for protein synthesis. Total RNAs were extracted from BAF-G277 cells, which had been deprived of IL-3 for 12 h and then stimulated with 0 (lanes 1 and 3) or 100 ng/ml of G-CSF for 1 h (lanes 2 and 4) in the absence (lanes 1 and 2) or presence (lanes 3 and 4) of 30-min pretreatment of cells with 10 μg/ml of cycloheximide, and were subjected to Northern blot analysis for c-myc and CHO-B mRNA expression as in A.

Mentions: We first characterized the nature of the gp130-mediated c-myc mRNA induction in BAF-G277, a BAF-B03 pro-B cell line expressing the chimeric receptor containing the extracellular domain of the G-CSF receptor and the transmembrane and cytoplasmic domains of gp130 (21). Total RNA was obtained from BAF-G277 cells which had been deprived of IL-3 for 12 h and then stimulated with 100 ng/ml of G-CSF for up to 15 h. The levels of mRNAs for the c-myc gene and a housekeeping gene, CHO-B, are shown (Fig. 1 A). The c-myc mRNA levels normalized with those of CHO-B were plotted (Fig. 1 B). G-CSF increased immediately the levels of c-myc mRNA by around sixfold with a peak at 1 h after stimulation, followed by a gradual decrease until 12 h and a slight increase at 15 h (Fig. 1 A, lanes 1–7; Fig. 1 B). This induction is due to the activation of the chimeric receptor since G-CSF did not increase c-myc mRNA level in the parental BAF/B03 cells (Fig. 1 A, lanes 8–10). Pretreatment of BAF-G277 with cycloheximide did not inhibit but rather enhanced the c-myc mRNA level at 1 h after stimulation with G-CSF, indicating that at least the initial phase of c-myc mRNA induction by gp130-mediated signals did not require de novo protein synthesis in BAF-G277 cells (Fig. 1 C, lanes 1–4).


STAT3 is required for the gp130-mediated full activation of the c-myc gene.

Kiuchi N, Nakajima K, Ichiba M, Fukada T, Narimatsu M, Mizuno K, Hibi M, Hirano T - J. Exp. Med. (1999)

Induction of c-myc mRNA expression via gp130 signaling in  BAF-G277 cells. (A) Northern blot analysis for c-myc mRNA expression  in G-CSF–stimulated BAF/B03 transfectants expressing a chimeric receptor consisting of the G-CSFR extracellular domain and the transmembrane and cytoplasmic domains of gp130, including the full-length, 277  amino acid–long cytoplasmic domain (BAF-G277). Total RNAs were  extracted from BAF-G277 cells (lanes 1–7) and parental BAF/B03 cells  (lanes 8–10) which had been deprived of IL-3 for 12 h and then stimulated with 100 ng/ml G-CSF for the indicated periods of time and subjected to Northern blot analysis for detection of c-myc mRNA (top) and  CHO-B mRNA (bottom), the latter being controls for the amounts of  loaded RNA. (B) Kinetic changes in the c-myc mRNA levels. Values for  c-myc mRNA levels were normalized to those for the corresponding  CHO-B mRNA levels and were plotted. Means ± SD of data from three  independent experiments are shown. (C) c-myc mRNA induction in the  presence of an inhibitor for protein synthesis. Total RNAs were extracted  from BAF-G277 cells, which had been deprived of IL-3 for 12 h and  then stimulated with 0 (lanes 1 and 3) or 100 ng/ml of G-CSF for 1 h  (lanes 2 and 4) in the absence (lanes 1 and 2) or presence (lanes 3 and 4) of  30-min pretreatment of cells with 10 μg/ml of cycloheximide, and were  subjected to Northern blot analysis for c-myc and CHO-B mRNA expression as in A.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1887683&req=5

Figure 1: Induction of c-myc mRNA expression via gp130 signaling in BAF-G277 cells. (A) Northern blot analysis for c-myc mRNA expression in G-CSF–stimulated BAF/B03 transfectants expressing a chimeric receptor consisting of the G-CSFR extracellular domain and the transmembrane and cytoplasmic domains of gp130, including the full-length, 277 amino acid–long cytoplasmic domain (BAF-G277). Total RNAs were extracted from BAF-G277 cells (lanes 1–7) and parental BAF/B03 cells (lanes 8–10) which had been deprived of IL-3 for 12 h and then stimulated with 100 ng/ml G-CSF for the indicated periods of time and subjected to Northern blot analysis for detection of c-myc mRNA (top) and CHO-B mRNA (bottom), the latter being controls for the amounts of loaded RNA. (B) Kinetic changes in the c-myc mRNA levels. Values for c-myc mRNA levels were normalized to those for the corresponding CHO-B mRNA levels and were plotted. Means ± SD of data from three independent experiments are shown. (C) c-myc mRNA induction in the presence of an inhibitor for protein synthesis. Total RNAs were extracted from BAF-G277 cells, which had been deprived of IL-3 for 12 h and then stimulated with 0 (lanes 1 and 3) or 100 ng/ml of G-CSF for 1 h (lanes 2 and 4) in the absence (lanes 1 and 2) or presence (lanes 3 and 4) of 30-min pretreatment of cells with 10 μg/ml of cycloheximide, and were subjected to Northern blot analysis for c-myc and CHO-B mRNA expression as in A.
Mentions: We first characterized the nature of the gp130-mediated c-myc mRNA induction in BAF-G277, a BAF-B03 pro-B cell line expressing the chimeric receptor containing the extracellular domain of the G-CSF receptor and the transmembrane and cytoplasmic domains of gp130 (21). Total RNA was obtained from BAF-G277 cells which had been deprived of IL-3 for 12 h and then stimulated with 100 ng/ml of G-CSF for up to 15 h. The levels of mRNAs for the c-myc gene and a housekeeping gene, CHO-B, are shown (Fig. 1 A). The c-myc mRNA levels normalized with those of CHO-B were plotted (Fig. 1 B). G-CSF increased immediately the levels of c-myc mRNA by around sixfold with a peak at 1 h after stimulation, followed by a gradual decrease until 12 h and a slight increase at 15 h (Fig. 1 A, lanes 1–7; Fig. 1 B). This induction is due to the activation of the chimeric receptor since G-CSF did not increase c-myc mRNA level in the parental BAF/B03 cells (Fig. 1 A, lanes 8–10). Pretreatment of BAF-G277 with cycloheximide did not inhibit but rather enhanced the c-myc mRNA level at 1 h after stimulation with G-CSF, indicating that at least the initial phase of c-myc mRNA induction by gp130-mediated signals did not require de novo protein synthesis in BAF-G277 cells (Fig. 1 C, lanes 1–4).

Bottom Line: STAT3 does so most likely by binding to cis-regulatory region(s) of the c-myc gene.We show that STAT3 binds to a region overlapping with the E2F site in the c-myc promoter and this site is critical for the c-myc gene promoter- driven transcriptional activation by IL-6 or gp130 signals.This is the first identification of the linkage between a member of the STAT family and the c-myc gene activation, and also explains how the IL-6 family of cytokines is capable of inducing the expression of the c-myc gene.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Suita, Osaka 565-0871, Japan.

ABSTRACT
The signal transducers and activators of transcription (STAT) family members have been implicated in regulating the growth, differentiation, and death of normal and transformed cells in response to either extracellular stimuli, including cytokines and growth factors, or intracellular tyrosine kinases. c-myc expression is coordinately regulated by multiple signals in these diverse cellular responses. We show that STAT3 mostly mediates the rapid activation of the c-myc gene upon stimulation of the interleukin (IL)-6 receptor or gp130, a signal transducing subunit of the receptor complexes for the IL-6 cytokine family. STAT3 does so most likely by binding to cis-regulatory region(s) of the c-myc gene. We show that STAT3 binds to a region overlapping with the E2F site in the c-myc promoter and this site is critical for the c-myc gene promoter- driven transcriptional activation by IL-6 or gp130 signals. This is the first identification of the linkage between a member of the STAT family and the c-myc gene activation, and also explains how the IL-6 family of cytokines is capable of inducing the expression of the c-myc gene.

Show MeSH
Related in: MedlinePlus