TY - JOUR
T1 - The 58-kDa microspherule protein (MSP58) represses human telomerase reverse transcriptase (hTERT) gene expression and cell proliferation by interacting with telomerase transcriptional element-interacting factor (TEIF)
AU - Hsu, Che Chia
AU - Chen, Chang Han
AU - Hsu, Tsung I.
AU - Hung, Jan Jong
AU - Ko, Jiunn Liang
AU - Zhang, Bo
AU - Lee, Yi Chao
AU - Chen, Han Ku
AU - Chang, Wen Chang
AU - Lin, Ding Yen
N1 - Funding Information:
We thank Dr. Kou-Juey Wu for the luciferase reporter plasmid TERTLuc800 and Dr. Yu-Ten Ju for the hTERT retrovirus vector pLPC-hTERT. We also thank Drs. Ming-Derg Lai, Chi-Wu Chiang, Ju-Ming Wang, Tsunglin Liu and Joseph T. Tseng for helpful discussion, Chia-Yang Hung, Shin-jin Lin and Yi-Chang Wang for assistance during animal experiments. The shRNA lentiviral vectors were obtained from the National RNAi Core Facility (The Institute of Molecular Biology/Genomic Research Center, Academia Sinica, Taiwan). We also thank the Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, for providing the instruments used for this study (CLRPG871342-3). This work was supported by grants from the National Science Council of Taiwan NSC98-2320-B-006-035-MY3 (to D.-Y. L.), NSC101-2320-B-038-022 (to W.-C. C.), NSC 100-2320-B-182A-001 ( NMRPG8A0011 ) (to C.-H. C.), National Cheng Kung University landmark grant ( C015 ) (to D.-Y. L.), and Kaohsiung Chang Gung Memorial Hospital CMRPG8A0391 , CMRPG8A0392 , CMRPG890921 , CMRPG8B1251 (to C.-H. C.).
PY - 2014/3
Y1 - 2014/3
N2 - 58-kDa microspherule protein (MSP58) plays an important role in a variety of cellular processes including transcriptional regulation, cell proliferation and oncogenic transformation. Currently, the mechanisms underlying the oncogenic effect of MSP58 are not fully understood. The human telomerase reverse transcriptase (hTERT) gene, which encodes an essential component for telomerase activity that is involved in cellular immortalization and transformation, is strictly regulated at the gene transcription level. Our previous study revealed a novel function of MSP58 in cellular senescence. Here we identify telomerase transcriptional element-interacting factor (TEIF) as a novel MSP58-interacting protein and determine the effect of MSP58 on hTERT transcription. This study thus provides evidence showing MSP58 to be a negative regulator of hTERT expression and telomerase activity. Luciferase reporter assays indicated that MSP58 could suppress the transcription of hTERT promoter. Additionally, stable overexpression of MSP58 protein in HT1080 and 293T cells decreased both endogenous hTERT expression and telomerase activity. Conversely, their upregulation was induced by MSP58 silencing. Chromatin immunoprecipitation assays showed that MSP58 binds to the hTERT proximal promoter. Furthermore, overexpression of MSP58 inhibited TEIF-mediated hTERT transactivation, telomerase activation, and cell proliferation promotion. The inhibitory effect of MSP58 occurred through inhibition of TEIF binding to DNA. Ultimately, the HT1080-implanted xenograft mouse model confirmed these cellular effects. Together, our findings provide new insights into both the biological function of MSP58 and the regulation of telomerase/hTERT expression.
AB - 58-kDa microspherule protein (MSP58) plays an important role in a variety of cellular processes including transcriptional regulation, cell proliferation and oncogenic transformation. Currently, the mechanisms underlying the oncogenic effect of MSP58 are not fully understood. The human telomerase reverse transcriptase (hTERT) gene, which encodes an essential component for telomerase activity that is involved in cellular immortalization and transformation, is strictly regulated at the gene transcription level. Our previous study revealed a novel function of MSP58 in cellular senescence. Here we identify telomerase transcriptional element-interacting factor (TEIF) as a novel MSP58-interacting protein and determine the effect of MSP58 on hTERT transcription. This study thus provides evidence showing MSP58 to be a negative regulator of hTERT expression and telomerase activity. Luciferase reporter assays indicated that MSP58 could suppress the transcription of hTERT promoter. Additionally, stable overexpression of MSP58 protein in HT1080 and 293T cells decreased both endogenous hTERT expression and telomerase activity. Conversely, their upregulation was induced by MSP58 silencing. Chromatin immunoprecipitation assays showed that MSP58 binds to the hTERT proximal promoter. Furthermore, overexpression of MSP58 inhibited TEIF-mediated hTERT transactivation, telomerase activation, and cell proliferation promotion. The inhibitory effect of MSP58 occurred through inhibition of TEIF binding to DNA. Ultimately, the HT1080-implanted xenograft mouse model confirmed these cellular effects. Together, our findings provide new insights into both the biological function of MSP58 and the regulation of telomerase/hTERT expression.
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U2 - 10.1016/j.bbamcr.2013.12.004
DO - 10.1016/j.bbamcr.2013.12.004
M3 - Article
C2 - 24361335
AN - SCOPUS:84891684664
SN - 0167-4889
VL - 1843
SP - 565
EP - 579
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
IS - 3
ER -