scholarly journals GmPTF1 Modifies Root Architecture Responses to Phosphate Starvation in Soybean

2019 ◽  
Author(s):  
Zhaojun Yang ◽  
Ying He ◽  
Yanxing Liu ◽  
Yelin Lai ◽  
Jiakun Zheng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Root Architecture ◽  
Bhlh Transcription Factor ◽  
Dependent Manner ◽  
Regulatory Factor ◽  
P Efficiency ◽  
Soybean Yield ◽  
Pi Starvation ◽  
Promoter Deletion Analysis ◽  
E Box

ABSTRACTThough root architecture modifications may be critically important for improving phosphorus (P) efficiency in crops, the regulatory mechanisms triggering these changes remain unclear. In this study, we demonstrate that genotypic variation in GmEXPB2 expression is strongly correlated with root elongation and P acquisition efficiency, and enhancing its transcription significantly improves soybean yield in the field. Promoter deletion analysis was performed using six 5’ truncation fragments (P1-P6) of GmEXPB2 fused with the GUS reporter gene in transgenic hairy roots, which revealed that the P1 segment containing 3 E-box elements significantly enhances induction of gene expression in response to phosphate (Pi) starvation. Further experimentation demonstrated that GmPTF1, a bHLH transcription factor, is the regulatory factor responsible for the induction of GmEXPB2 expression in response to Pi starvation. In short, Pi starvation induced expression of GmPTF1, with the GmPTF1 product not only directly binding the E-box motif in the P1 region of the GmEXPB2 promoter, but also activating GUS expression in a dosage dependent manner. Further work with soybean transgenic composite plants showed that, altering GmPTF1 expression significantly impacted GmEXPB2 transcription, and thereby affected root growth, biomass and P uptake. Taken together, this work identifies a novel regulatory factor, GmPTF1, involved in changing soybean root architecture through regulation the expression of GmEXPB2. These findings contribute to understanding the molecular basis of root architecture modifications in response to P deficiency, and, in the process, suggest candidate genes and a promoter region to target for improving soybean yield through molecular breeding of P efficiency.One Sentence SummaryThe bHLH transcription factor GmPTF1 regulates the expression of β-expansin gene GmEXPB2 to modify root architecture, and thus promote phosphate acquisition, and biomass in soybean.

scholarly journals Modulation of the Expression and Transactivation of Androgen Receptor by the Basic Helix-Loop-Helix Transcription Factor Pod-1 through Recruitment of Histone Deacetylase 1

2005 ◽  
Vol 19 (9) ◽  
pp. 2245-2257 ◽  
Author(s):  
Cheol Yi Hong ◽  
Eun-Yeung Gong ◽  
Kabsun Kim ◽  
Ji Ho Suh ◽  
Hyun-Mi Ko ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Androgen Receptor ◽  
Histone Deacetylase ◽  
Promoter Activity ◽  
Bhlh Transcription Factor ◽  
Dependent Manner ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
E Box ◽  
And Function

Abstract Androgen receptor (AR) is important in male sexual differentiation and testicular function. Here, we demonstrate the regulation of AR expression and its transactivation by the basic helix-loop-helix (bHLH) transcription factor Pod-1, the expression of which in postnatal testis reciprocally coincides with the expression of AR. Pod-1 represses the promoter activity of AR, possibly through its E-box. An AR promoter region of 169 bp, which harbors one canonical E-box, is sufficient for the Pod-1-repression and bound by purified Pod-1 proteins. Pod-1 also suppresses the transactivation of AR. Transient transfection analyses of mammalian cells show that Pod-1 represses AR transactivation in a dose-dependent manner. Furthermore, yeast two-hybrid, glutathione-S-transferase-pull-down, and coimmunoprecipitation analyses reveal that Pod-1 directly associates with AR through its N-terminal region and through the DNA binding-hinge domain of AR. Interestingly, Pod-1 recruits histone deacetylase (HDAC)-1 to inhibit both promoter activity and transactivation of AR. Overexpression of HDAC1 further inhibits the Pod-1-mediated repressions and Pod-1 directly interacts with HDAC1. Furthermore, chromatin immunoprecipitation assay reveals that HDAC1 is recruited with Pod-1 to the endogenous AR promoter and the androgen-regulated Pem promoter. Taken together, these results suggest that Pod-1, which controls AR transcription and function, may play an important role in the development and function of the testis.

scholarly journals The MNT transcription factor autoregulates its expression and supports proliferation in MYC-associated factor X (MAX)-deficient cells

2020 ◽  
Vol 295 (7) ◽  
pp. 2001-2017 ◽  
Author(s):  
M. Carmen Lafita-Navarro ◽  
Judit Liaño-Pons ◽  
Andrea Quintanilla ◽  
Ignacio Varela ◽  
Rosa Blanco ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transcription Factor ◽  
Transcriptional Regulator ◽  
Bhlh Transcription Factor ◽  
Factor X ◽  
Associated Factor ◽  
Helix Loop Helix ◽  
E Box ◽  
E Boxes ◽  
Cycle Regulation

The MAX network transcriptional repressor (MNT) is an MXD family transcription factor of the basic helix-loop-helix (bHLH) family. MNT dimerizes with another transcriptional regulator, MYC-associated factor X (MAX), and down-regulates genes by binding to E-boxes. MAX also dimerizes with MYC, an oncogenic bHLH transcription factor. Upon E-box binding, the MYC–MAX dimer activates gene expression. MNT also binds to the MAX dimerization protein MLX (MLX), and MNT–MLX and MNT–MAX dimers co-exist. However, all MNT functions have been attributed to MNT–MAX dimers, and no functions of the MNT–MLX dimer have been described. MNT's biological role has been linked to its function as a MYC oncogene modulator, but little is known about its regulation. We show here that MNT localizes to the nucleus of MAX-expressing cells and that MNT–MAX dimers bind and repress the MNT promoter, an effect that depends on one of the two E-boxes on this promoter. In MAX-deficient cells, MNT was overexpressed and redistributed to the cytoplasm. Interestingly, MNT was required for cell proliferation even in the absence of MAX. We show that in MAX-deficient cells, MNT binds to MLX, but also forms homodimers. RNA-sequencing experiments revealed that MNT regulates the expression of several genes even in the absence of MAX, with many of these genes being involved in cell cycle regulation and DNA repair. Of note, MNT–MNT homodimers regulated the transcription of some genes involved in cell proliferation. The tight regulation of MNT and its functionality even without MAX suggest a major role for MNT in cell proliferation.

scholarly journals Loss of function of bHLH transcription factor Nrd1 in tomato induces an arabinogalactan protein-encoding gene and enhances resistance to Pseudomonas syringae pv. tomato

2021 ◽  
Author(s):  
Ning Zhang ◽  
Chloe Hecht ◽  
Xuepeng Sun ◽  
Zhangjun Fei ◽  
Gregory B Martin
Keyword(s):  
Transcription Factor ◽  
Pseudomonas Syringae ◽  
Transcript Abundance ◽  
Negative Regulator ◽  
Arabinogalactan Protein ◽  
Bhlh Transcription Factor ◽  
Dependent Manner ◽  
Rna Seq ◽  
Loss Of Function ◽  
Encoding Gene

Basic helix-loop-helix (bHLH) transcription factors constitute a superfamily in eukaryotes but their roles in plant immunity remain largely uncharacterized. We found that the transcript abundance in tomato leaves of one bHLH transcription factor-encoding gene, Nrd1 (negative regulator of resistance to DC3000 1), was significantly increased after treatment with the immunity-inducing flgII-28 peptide. Plants carrying a loss-of-function mutation in Nrd1 (Δnrd1) showed enhanced resistance to Pseudomonas syringae pv. tomato (Pst) DC3000 although early pattern-triggered immunity responses such as generation of reactive oxygen species and activation of mitogen-activated protein kinases after treatment with flagellin-derived flg22 and flgII-28 peptides were unaltered compared to wild-type plants. An RNA-Seq analysis identified a gene, Agp1, whose expression is strongly suppressed in an Nrd1-dependent manner. Agp1 encodes an arabinogalactan protein and overexpression of the Agp1 gene in Nicotiana benthamiana led to ~10-fold less Pst growth compared to the control. These results suggest that the Nrd1 protein promotes tomato susceptibility to Pst by suppressing the defense gene Agp1. RNA-Seq also revealed that loss of Nrd1 function has no effect on the transcript abundance of immunity-associated genes including Bti9, Core, Fls2, Fls3 and Wak1 upon Pst inoculation, suggesting that the enhanced immunity observed in the Δnrd1 mutants is due to the activation of key PRR signaling components as well as loss of Nrd1-regulated suppression of Agp1.

scholarly journals Menin enhances c-Myc-mediated transcription to promote cancer progression

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Gongwei Wu ◽  
Mengqiu Yuan ◽  
Shengqi Shen ◽  
Xiaoyu Ma ◽  
Jingwen Fang ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Essential Role ◽  
Target Genes ◽  
Dependent Manner ◽  
Regulatory Factor ◽  
E Box ◽  
Unique Ability

Abstract Menin is an enigmatic protein that displays unique ability to either suppress or promote tumorigenesis in a context-dependent manner. The role for Menin to promote oncogenic functions has been largely attributed to its essential role in forming the MLL methyltransferase complex, which mediates H3K4me3. Here, we identify an unexpected role of Menin in enhancing the transactivity of oncogene MYC in a way independent of H3K4me3 activity. Intriguingly, we find that Menin interacts directly with the TAD domain of MYC and co-localizes with MYC to E-Box to enhance the transcription of MYC target genes in a P-TEFb-dependent manner. We further demonstrate that, by transcriptionally promoting the expression of MYC target genes in cancer cells, Menin stimulates cell proliferation and cellular metabolism both in vitro and in vivo. Our results uncover a previously unappreciated mechanism by which Menin functions as an oncogenic regulatory factor that is critical for MYC-mediated gene transcription.

scholarly journals ETS variant transcription factor 5 and c-Myc cooperate in derepressing the human telomerase gene promoter via composite ETS/E-box motifs

2020 ◽  
Vol 295 (29) ◽  
pp. 10062-10075
Author(s):  
Fan Zhang ◽  
Shuwen Wang ◽  
Jiyue Zhu
Keyword(s):  
Transcription Factor ◽  
Core Promoter ◽  
Human Fibroblasts ◽  
Regulatory Elements ◽  
Bhlh Transcription Factor ◽  
Htert Promoter ◽  
E Box ◽  
Ets Family ◽  
Human Telomerase ◽  
Factor C

The human telomerase gene (hTERT) is repressed in most somatic cells. How transcription factors activate the hTERT promoter in its repressive chromatin environment is unknown. Here, we report that the ETS family protein ETS variant transcription factor 5 (ETV5) mediates epidermal growth factor (EGF)-induced hTERT expression in MCF10A cells. This activation required MYC proto-oncogene bHLH transcription factor (c-Myc) and depended on the chromatin state of the hTERT promoter. Using chromatinized bacterial artificial chromosome (BAC) reporters in human fibroblasts, we found that ETV5 and c-Myc/MYC-associated factor X (MAX) synergistically activate the hTERT promoter via two identical, but inverted, composite Ets/E-box motifs enclosing the core promoter. Mutations of Ets or E-box sites in either DNA motif abolished the activation and reduced or eliminated the synergism. ETV5 and c-Myc facilitated each other's binding to the hTERT promoter. ETV5 bound to the hTERT promoter in both telomerase-negative and -positive cells, but it activated the repressed hTERT promoter and altered histone modifications only in telomerase-negative cells. The synergistic ETV5/c-Myc activation disappeared when hTERT promoter repression became relieved because of the loss of distal regulatory elements in chimeric human/mouse BAC reporters. Our results suggest that the binding of c-Myc and ETS family proteins to the Ets/E-box motifs derepresses the hTERT promoter by inducing an active promoter configuration, providing a mechanistic insight into hTERT activation during tumorigenesis.

scholarly journals BETA3, a novel helix-loop-helix protein, can act as a negative regulator of BETA2 and MyoD-responsive genes.

1996 ◽  
Vol 16 (2) ◽  
pp. 626-633 ◽  
Author(s):  
M Peyton ◽  
C M Stellrecht ◽  
F J Naya ◽  
H P Huang ◽  
P J Samora ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Negative Regulator ◽  
Bhlh Transcription Factor ◽  
Pcr Cloning ◽  
Specific Expression ◽  
Class A ◽  
Helix Loop Helix ◽  
E Box ◽  
Class B ◽  
Bhlh Factors

Using degenerate PCR cloning we have identified a novel basic helix-loop-helix (bHLH) transcription factor, BETA3, from a hamster insulin tumor (HIT) cell cDNA library. Sequence analysis revealed that this factor belongs to the class B bHLH family and has the highest degree of homology with another bHLH transcription factor recently isolated in our laboratory, BETA2 (neuroD) (J. E. Lee, S. M. Hollenberg, L. Snider, D. L. Turner, N. Lipnick, and H. Weintraub, Science 268:836-844, 1995; F. J. Naya, C. M. M. Stellrecht, and M.-J. Tsai, Genes Dev. 8:1009-1019, 1995). BETA2 is a brain- and pancreatic-islet-specific bHLH transcription factor and is largely responsible for the tissue-specific expression of the insulin gene. BETA3 was found to be tissue restricted, with the highest levels of expression in HIT, lung, kidney, and brain cells. Surprisingly, despite the homology between BETA2 and BETA3 and its intact basic region, BETA3 is unable to bind the insulin E box in bandshift analysis as a homodimer or as a heterodimer with the class A bHLH factors E12, E47, or BETA1. Instead, BETA3 inhibited both the E47 homodimer and the E47/BETA2 heterodimer binding to the insulin E box. In addition, BETA3 greatly repressed the BETA2/E47 induction of the insulin enhancer in HIT cells as well as the MyoD/E47 induction of a muscle-specific E box in the myoblast cell line C2C12. In contrast, expression of BETA3 had no significant effect on the GAL4-VP16 transcriptional activity. Immunoprecipitation analysis demonstrates that the mechanism of repression is via direct protein-protein interaction, presumably by heterodimerization between BETA3 and class A bHLH factors.

Abstract 150: Novel Mechanism for Regulation of Extracellular SOD Expression and Activity by Antioxidant-1

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Kiyoshi Ozumi ◽  
Ha Won Kim ◽  
Shinichi Itoh ◽  
Ronald Mckinney ◽  
Rodney Folz ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Oxidant Stress ◽  
Mouse Fibroblast ◽  
Copper Chaperone ◽  
Dependent Manner ◽  
Chaperone Function ◽  
Promoter Deletion Analysis ◽  
Stress Dependent ◽  
Mouse Aorta ◽  
Expression And Activity

Extracellular superoxide dismutase (ecSOD), a copper-containing secretory antioxidant enzyme, plays an important role in various oxidative stress-dependent cardiovascular diseases. Little is known regarding the mechanisms by which ecSOD expression and activity are regulated. We previously demonstrated that antioxidant-1 (Atox1) functions as a copper chaperone for ecSOD at transGolgi network (TGN) to regulate its activity. Unexpectedly, we also found that ecSOD mRNA is markedly decreased in Atox1-knockout (KO) fibroblasts. We thus hypothesize that Atox1 functions not only as copper chaperone but also as transcription factor to regulate both expression and activity of ecSOD. Here we show that in ApoE-KO mouse aorta, Atox1 was intensely stained in the nucleus at the intimal lesion of atherosclerosis where ecSOD was highly expressed. In cultured mouse fibroblast, copper treatment stimulated translocation of Atox1 from the cytosol to the nucleus. The ecSOD mRNA and its promoter activity were markedly decreased in Atox1 KO cells (82.5% and 85.7% decrease, respectively). Promoter deletion analysis identified Atox1-response element (Atox1-RE) at −314/−304 segment of ecSOD promoter. Gel shift and ChIP assays showed that Atox1 directly bound to the Atox1-RE including DNA segment in a copper dependent manner. To segregate a transcription factor and a copper chaperone function of Atox1, we generated adenovirus expressing wild-type, nucleus-targeted, and TGN-targeted Atox1 (Atox1-WT, Atox1-NLS, and Atox1-TGN). Re-expression of either Atox1-NLS or Atox1-WT, but not Atox1-TGN, in Atox1-KO cells increased ecSOD mRNA by 3.2-and 2.5-fold, respectively. Importantly, re-expression of either Atox1-WT only or both Atox1-NLS and Atox1-TGN in Atox1 KO cells increased ecSOD activity (2.1- and 2.7-fold, respectively), while either Atox1-NLS or Atox1-TGN alone had no effect. In summary, Atox1 functions as a novel copper dependent transcription factor to increase ecSOD expression, and modulates ecSOD activity through both copper chaperone and transcription factor function. Thus, not only ecSOD but also Atox1 are potential therapeutic targets for oxidant stress-dependent cardiovascular disease such as atherosclerosis.

Sign in / Sign up

Export Citation Format

Share Document