Sp1 and Sp3 are involved in the full transcriptional activity of centromere protein H in human nasopharyngeal carcinoma cells.
The overexpression of centromere protein H (CENPH), one of the fundamental components of the human active kinetochore, has been shown to be closely associated with human cancers. However, the mechanism of its transcriptional regulation has not been reported. The aim of the present study was to investigate the regulatory elements for the transcriptional regulation of CENPH in nasopharyngeal carcinoma cells. To characterize the CENPH promoter and identify regulatory elements, we cloned 1015 bp (-975/+40 bp) of the 5'-flanking region of the CENPH gene from immortalized normal nasopharyngeal epithelial cells (Bmi-1/NPEC). Functional analysis established a minimal region (-140/-87 bp) involved in the regulation of human CENPH promoter activity. Through site-directed mutagenesis, a transactivation assay, chromatin immunoprecipitation, and electrophoretic mobility shift assay, we found that the Sp1/Sp3 transcription factors could bind to the CENPH promoter in vitro and in vivo, and that they regulated CENPH promoter activation in human nasopharyngeal carcinoma cells. Furthermore, Sp1 and Sp3 were highly expressed in nasopharyngeal carcinoma cells. Knockdown of Sp1 and Sp3 by small interfering RNA or inhibition of Sp1 and Sp3 activity by mithramycin A decreased CENPH mRNA expression, whereas the exogenous expression of Sp1 and Sp3 upregulated CENPH mRNA expression. Taken together, our results indicate that Sp1 and Sp3 bind to the CENPH minimal promoter and function as a regulator of the transcription of CENPH in human nasopharyngeal carcinomas.
State Key Laboratory of Oncology in South China, SunYat-sen University Cancer Center, Guangzhou, China.
Wei-feng
WF
Zhao
Hong-bo
HB
Wang
Bo
B
Xie
Li-juan
LJ
Hu
Li-hua
LH
Xu
Bo-hua
BH
Kuang
Man-zhi
MZ
Li
Xing
X
Zhang
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002277:Carcinoma; D045744:Cell Line, Tumor; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D055785:Gene Knockdown Techniques; D006801:Humans; D016297:Mutagenesis, Site-Directed; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000378:metabolism*; D008926:Plicamycin / Q000031:analogs & derivatives / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional; D016329:Sp1 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
C121933:CENPH protein, human; D002868:Chromosomal Proteins, Non-Histone; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C497121:SP3 protein, human; D016329:Sp1 Transcription Factor; D051705:Sp3 Transcription Factor; C066851:mithramycin A; D008926:Plicamycin