TY - JOUR
T1 - Overexpression of D-type cyclins, E2F-1, SV40 large T antigen and HPV16 E7 rescue cell cycle arrest of tsBN462 cells caused by the CCG1/TAF(II)250 mutation
AU - Sekiguchi, Takeshi
AU - Nishimoto, Takeharu
AU - Hunter, Tony
N1 - Funding Information:
We thank the members of the Hunter/Eckhart laboratory and Nishimoto laboratory for help and discussions. We thank J Fukumura for technical assistance. We thank D Chambers for his help with FACScan analysis. This work was supported by a grant-in-aid for scientific and cancer research from the Ministry of Education, Science and Culture of Japan (TS, TN) and by USPHS grants CA14195 and CA39780 (TH). TH is a Frank and Else Schilling American Cancer Society Research Professor.
PY - 1999/3/11
Y1 - 1999/3/11
N2 - tsBN462 cells, which have a point mutation in CCG1/TAF(II)250, a component of TFIID complex, arrest in G1 at the nonpermissive temperature of 39.5°C. Overexpression of D-type cyclins rescued the cell cycle arrest of tsBN462 cells, suggesting that the cell cycle arrest was through Rb. Consistent with this, overexpression of E2F-1, whose function is repressed by the hypophosphorylated form of Rb, also rescued the cell cycle arrest. Moreover, expression of the viral oncoproteins SV40 large T antigen and HPV16 E7, which both bind Rb and inactivate its function, rescued the cell cycle arrest, whereas HPV16 E6 did not. Mutation of the Rb-binding motif in E7 abrogated its ability to rescue the cell cycle arrest. Expression of exogenous cyclin D1, SV40 large T antigen or CCG1/TAF(II)250 increased cyclin A expression at 39.5°C. Coexpression of HPV16 E7 and adenovirus E1b19K, which blocks apoptosis, rescued the proliferation of tsBN462 cells at 38.5°C. To investigate the mechanism underlying the lack of cyclin D1 expression, deletion analaysis of cyclin D1 promoter was performed. The 0.15 kbp cyclin D1 core promoter region, which lacks any transcription factor binding motifs, still exhibited a temperature-sensitive phenotype in tsBN462 cells suggesting that CCG1/TAF(II)250 is critical for the function of the cyclin D1 core promoter.
AB - tsBN462 cells, which have a point mutation in CCG1/TAF(II)250, a component of TFIID complex, arrest in G1 at the nonpermissive temperature of 39.5°C. Overexpression of D-type cyclins rescued the cell cycle arrest of tsBN462 cells, suggesting that the cell cycle arrest was through Rb. Consistent with this, overexpression of E2F-1, whose function is repressed by the hypophosphorylated form of Rb, also rescued the cell cycle arrest. Moreover, expression of the viral oncoproteins SV40 large T antigen and HPV16 E7, which both bind Rb and inactivate its function, rescued the cell cycle arrest, whereas HPV16 E6 did not. Mutation of the Rb-binding motif in E7 abrogated its ability to rescue the cell cycle arrest. Expression of exogenous cyclin D1, SV40 large T antigen or CCG1/TAF(II)250 increased cyclin A expression at 39.5°C. Coexpression of HPV16 E7 and adenovirus E1b19K, which blocks apoptosis, rescued the proliferation of tsBN462 cells at 38.5°C. To investigate the mechanism underlying the lack of cyclin D1 expression, deletion analaysis of cyclin D1 promoter was performed. The 0.15 kbp cyclin D1 core promoter region, which lacks any transcription factor binding motifs, still exhibited a temperature-sensitive phenotype in tsBN462 cells suggesting that CCG1/TAF(II)250 is critical for the function of the cyclin D1 core promoter.
UR - http://www.scopus.com/inward/record.url?scp=0033545564&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033545564&partnerID=8YFLogxK
U2 - 10.1038/sj.onc.1202508
DO - 10.1038/sj.onc.1202508
M3 - Article
C2 - 10086334
AN - SCOPUS:0033545564
VL - 18
SP - 1797
EP - 1806
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 10
ER -