scholarly journals Mutation of DNA primase causes extensive apoptosis of retinal neurons through the activation of DNA damage checkpoint and tumor suppressor p53

Development ◽  
2008 ◽  
Vol 135 (7) ◽  
pp. 1247-1257 ◽  
Author(s):  
M. Yamaguchi ◽  
N. Fujimori-Tonou ◽  
Y. Yoshimura ◽  
T. Kishi ◽  
H. Okamoto ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Dna Damage Checkpoint ◽  
Retinal Neurons ◽  
Tumor Suppressor P53 ◽  
Dna Primase

scholarly journals Tumor Suppressor p53 Stimulates the Expression of Epstein-Barr Virus Latent Membrane Protein 1

2017 ◽  
Vol 91 (20) ◽  
Author(s):  
Qianli Wang ◽  
Amy Lingel ◽  
Vicki Geiser ◽  
Zachary Kwapnoski ◽  
Luwen Zhang
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Epstein Barr Virus ◽  
Latent Membrane Protein ◽  
Latent Membrane Protein 1 ◽  
Tumor Suppressor P53 ◽  
Viral Oncogene ◽  
Barr Virus ◽  
Lmp1 Expression ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) is associated with multiple human malignancies. EBV latent membrane protein 1 (LMP1) is required for the efficient transformation of primary B lymphocytes in vitro and possibly in vivo. The tumor suppressor p53 plays a seminal role in cancer development. In some EBV-associated cancers, p53 tends to be wild type and overly expressed; however, the effects of p53 on LMP1 expression is not clear. We find LMP1 expression to be associated with p53 expression in EBV-transformed cells under physiological and DNA damaging conditions. DNA damage stimulates LMP1 expression, and p53 is required for the stimulation. Ectopic p53 stimulates endogenous LMP1 expression. Moreover, endogenous LMP1 blocks DNA damage-mediated apoptosis. Regarding the mechanism of p53-mediated LMP1 expression, we find that interferon regulatory factor 5 (IRF5), a direct target of p53, is associated with both p53 and LMP1. IRF5 binds to and activates a LMP1 promoter reporter construct. Ectopic IRF5 increases the expression of LMP1, while knockdown of IRF5 leads to reduction of LMP1. Furthermore, LMP1 blocks IRF5-mediated apoptosis in EBV-infected cells. All of the data suggest that cellular p53 stimulates viral LMP1 expression, and IRF5 may be one of the factors for p53-mediated LMP1 stimulation. LMP1 may subsequently block DNA damage- and IRF5-mediated apoptosis for the benefits of EBV. The mutual regulation between p53 and LMP1 may play an important role in EBV infection and latency and its related cancers. IMPORTANCE The tumor suppressor p53 is a critical cellular protein in response to various stresses and dictates cells for various responses, including apoptosis. This work suggests that an Epstein-Bar virus (EBV) principal viral oncogene is activated by cellular p53. The viral oncogene blocks p53-mediated adverse effects during viral infection and transformation. Therefore, the induction of the viral oncogene by p53 provides a means for the virus to cope with infection and DNA damage-mediated cellular stresses. This seems to be the first report that p53 activates a viral oncogene; therefore, the discovery would be interesting to a broad readership from the fields of oncology to virology.

scholarly journals Double-Stranded-RNA-Activated Protein Kinase PKR Enhances Transcriptional Activation by Tumor Suppressor p53

1999 ◽  
Vol 19 (4) ◽  
pp. 2475-2484 ◽  
Author(s):  
Andrew R. Cuddihy ◽  
Suiyang Li ◽  
Nancy Wai Ning Tam ◽  
Andrew Hoi-Tao Wong ◽  
Yoichi Taya ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Transcriptional Activation ◽  
Kinase Inhibitor ◽  
Regulation Of Gene Expression ◽  
Temperature Sensitive ◽  
Tumor Suppressor P53 ◽  
Double Stranded Rna ◽  
Genes Encoding ◽  
Inducible Genes

ABSTRACT The tumor suppressor p53 plays a key role in inducing G1 arrest and apoptosis following DNA damage. The double-stranded-RNA-activated protein PKR is a serine/threonine interferon (IFN)-inducible kinase which plays an important role in regulation of gene expression at both transcriptional and translational levels. Since a cross talk between IFN-inducible proteins and p53 had already been established, we investigated whether and how p53 function was modulated by PKR. We analyzed p53 function in several cell lines derived from PKR+/+ and PKR−/− mouse embryonic fibroblasts (MEFs) after transfection with the temperature-sensitive (ts) mutant of mouse p53 [p53(Val135)]. Here we report that transactivation of transcription by p53 and G0/G1 arrest were impaired in PKR−/− cells upon conditions that ts p53 acquired a wild-type conformation. Phosphorylation of mouse p53 on Ser18 was defective in PKR−/− cells, consistent with an impaired transcriptional induction of the p53-inducible genes encoding p21WAF/Cip1 and Mdm2. In addition, Ser18 phosphorylation and transcriptional activation by mouse p53 were diminished in PKR−/− cells after DNA damage induced by the anticancer drug adriamycin or γ radiation but not by UV radiation. Furthermore, the specific phosphatidylinositol-3 (PI-3) kinase inhibitor LY294002 inhibited the induction of phosphorylation of Ser18 of p53 by adriamycin to a higher degree in PKR+/+ cells than in PKR−/− cells. These novel findings suggest that PKR enhances p53 transcriptional function and implicate PKR in cell signaling elicited by a specific type of DNA damage that leads to p53 phosphorylation, possibly through a PI-3 kinase pathway.

scholarly journals DMPK is a New Candidate Mediator of Tumor Suppressor p53-Dependent Cell Death

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3175
Author(s):  
Katsuhiko Itoh ◽  
Takahiro Ebata ◽  
Hiroaki Hirata ◽  
Takeru Torii ◽  
Wataru Sugimoto ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Tumor Suppressor ◽  
Dependent Manner ◽  
Tumor Suppressor P53 ◽  
P53 Family ◽  
Gene Encoding ◽  
Myotonic Dystrophy Protein Kinase ◽  
Induced Apoptosis ◽  
Actomyosin Contraction

Tumor suppressor p53 plays an integral role in DNA-damage induced apoptosis, a biological process that protects against tumor progression. Cell shape dramatically changes when cells undergo apoptosis, which is associated with actomyosin contraction; however, it remains entirely elusive how p53 regulates actomyosin contraction in response to DNA-damaging agents. To identify a novel p53 regulating gene encoding the modulator of myosin, we conducted DNA microarray analysis. We found that, in response to DNA-damaging agent doxorubicin, expression of myotonic dystrophy protein kinase (DMPK), which is known to upregulate actomyosin contraction, was increased in a p53-dependent manner. The promoter region of DMPK gene contained potential p53-binding sequences and its promoter activity was increased by overexpression of the p53 family protein p73, but, unexpectedly, not of p53. Furthermore, we found that doxorubicin treatment induced p73 expression, which was significantly attenuated by downregulation of p53. These data suggest that p53 induces expression of DMPK through upregulating p73 expression. Overexpression of DMPK promotes contraction of the actomyosin cortex, which leads to formation of membrane blebs, loss of cell adhesion, and concomitant caspase activation. Taken together, our results suggest the existence of p53-p73-DMPK axis which mediates DNA-damage induced actomyosin contraction at the cortex and concomitant cell death.

Inhibitory role of E2F-1 in the regulation of tumor suppressor p53 during DNA damage response

2012 ◽  
Vol 421 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Yukari Yoshihara ◽  
Dan Wu ◽  
Natsumi Kubo ◽  
Meixiang Sang ◽  
Akira Nakagawara ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Dna Damage Response ◽  
Tumor Suppressor P53 ◽  
Inhibitory Role ◽  
Damage Response

scholarly journals RUNX3 Modulates DNA Damage-mediated Phosphorylation of Tumor Suppressor p53 at Ser-15 and Acts as a Co-activator for p53

2010 ◽  
Vol 285 (22) ◽  
pp. 16693-16703 ◽  
Author(s):  
Chizu Yamada ◽  
Toshinori Ozaki ◽  
Kiyohiro Ando ◽  
Yusuke Suenaga ◽  
Ken-ichi Inoue ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Tumor Suppressor P53

scholarly journals Mediator of DNA damage checkpoint 1 (MDC1) is a novel estrogen receptor co-regulator in invasive lobular carcinoma of the breast

2020 ◽  
Author(s):  
Evelyn K. Bordeaux ◽  
Joseph L. Sottnik ◽  
Sanjana Mehrotra ◽  
Sarah E. Ferrara ◽  
Andrew E. Goodspeed ◽  
...  
Keyword(s):  
Dna Damage ◽  
Estrogen Receptor ◽  
Tumor Suppressor ◽  
Cell Lines ◽  
Invasive Lobular Carcinoma ◽  
Ductal Carcinoma ◽  
Lobular Carcinoma ◽  
Laboratory Data ◽  
Published Data ◽  
Dna Damage Checkpoint

ABSTRACTInvasive lobular carcinoma (ILC) is the most common histological subtype of breast cancer, and nearly all ILC tumors express estrogen receptor alpha (ER). However, clinical and laboratory data suggest ILC are strongly estrogen-driven but not equally sensitive to anti-estrogen therapies. We hypothesized that ILC-specific ER transcriptional co-regulators mediate ER functions in ILC and anti-estrogen resistance, and profiled ER-associated proteins by mass spectrometry. Three ER+ ILC cell lines, MDA MB 134VI, SUM44PE, and BCK4, were compared to published data from ER+ invasive ductal carcinoma (IDC) cell lines, and we examined whether siRNA knockdown of identified proteins suppressed ER-driven proliferation in ILC cells. This approach found mediator of DNA damage checkpoint 1 (MDC1), a key tumor suppressor in DNA damage response (DDR), as a putative novel ER co-regulator in ILC. We confirmed ER:MDC1 interaction was specific to ILC cell lines versus IDC cells, and found MDC1 knockdown suppressed ILC cell proliferation and suppressed tamoxifen resistance in MDA MB 134VI. Using RNA-sequencing, we found that in ILC cells, MDC1 knockdown broadly dysregulates the estrogen-driven ER transcriptome, with ER:MDC1 target genes enriched for hormone-response-elements in their promoter regions. Importantly, our data are inconsistent with MDC1 regulating ER via MDC1 DDR and tumor suppressor functions, but instead suggest a novel oncogenic role for MDC1 in mediating ER transcriptional activity as a co-regulator. Supporting this, in breast tumor tissue microarrays MDC1 protein was frequently low or absent in IDC or ER-ILC, but MDC1 loss is rare in ER+ ILC. ER:MDC1 interaction and MDC1 co-regulator functions may underlie cell type-specific ER functions in ILC, and serve as important biomarkers and therapeutic targets to overcome anti-estrogen resistance in ILC.

Sign in / Sign up

Export Citation Format

Share Document