TY - JOUR
T1 - Bcl3, an IκB protein, stimulates activating protein-1 transactivation and cellular proliferation
AU - Na, Soon Young
AU - Choi, Ji Eun
AU - Kim, Han Jong
AU - Jhun, Byung Hak
AU - Lee, Young Chul
AU - Lee, Jae Woon
PY - 1999/10/1
Y1 - 1999/10/1
N2 - Bcl3, an IκB protein, was originally isolated as a putative proto- oncogene in a subset of B cell chronic lymphocytic leukemias. Bcl3 was subsequently shown to associate tightly with and transactivate the NFκB p50 or p52 homodimer. Herein, we show that Bcl3 stimulates the activating protein-1 (AP-1) transactivation, either alone or in conjunction with transcription integrators steroid receptor coactivator-1 and CREB-binding protein/p300. The C-terminal 158 residues of Bcl3 exhibited an autonomous transactivation function and interacted with specific subregions of the AP-1 components c-Jun and c-Fos, CREB-binding protein/p300, and steroid receptor coactivator-1, as demonstrated by the yeast and mammalian two-hybrid tests as well as glutathione S-transferase pull-down assays. In addition, anti-HA antibody co-precipitated c-Jun from HeLa cells co-expressing c-Jun and HA- tagged Bcl3, consistent with the idea that Bcl3 directly associates with AP-1 in vivo. Furthermore, microinjection of Bcl3 expression vector into Rat-1 fibroblast cells significantly enhanced DNA synthesis and expression of c- jun, one of the cellular target genes of AP-1. These results suggest that Bcl3 may directly participate in the tumorigenesis processes as a novel transcription coactivator of the mitogenic transcription factor AP-1 in vivo.
AB - Bcl3, an IκB protein, was originally isolated as a putative proto- oncogene in a subset of B cell chronic lymphocytic leukemias. Bcl3 was subsequently shown to associate tightly with and transactivate the NFκB p50 or p52 homodimer. Herein, we show that Bcl3 stimulates the activating protein-1 (AP-1) transactivation, either alone or in conjunction with transcription integrators steroid receptor coactivator-1 and CREB-binding protein/p300. The C-terminal 158 residues of Bcl3 exhibited an autonomous transactivation function and interacted with specific subregions of the AP-1 components c-Jun and c-Fos, CREB-binding protein/p300, and steroid receptor coactivator-1, as demonstrated by the yeast and mammalian two-hybrid tests as well as glutathione S-transferase pull-down assays. In addition, anti-HA antibody co-precipitated c-Jun from HeLa cells co-expressing c-Jun and HA- tagged Bcl3, consistent with the idea that Bcl3 directly associates with AP-1 in vivo. Furthermore, microinjection of Bcl3 expression vector into Rat-1 fibroblast cells significantly enhanced DNA synthesis and expression of c- jun, one of the cellular target genes of AP-1. These results suggest that Bcl3 may directly participate in the tumorigenesis processes as a novel transcription coactivator of the mitogenic transcription factor AP-1 in vivo.
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U2 - 10.1074/jbc.274.40.28491
DO - 10.1074/jbc.274.40.28491
M3 - Article
C2 - 10497212
AN - SCOPUS:0033201447
SN - 0021-9258
VL - 274
SP - 28491
EP - 28496
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 40
ER -