scholarly journals Reciprocal cross-regulation of VND and SND multigene TF families for wood formation in Populus trichocarpa

2017 ◽  
Vol 114 (45) ◽  
pp. E9722-E9729 ◽  
Author(s):  
Ying-Chung Jimmy Lin ◽  
Hao Chen ◽  
Quanzi Li ◽  
Wei Li ◽  
Jack P. Wang ◽  
...  

Secondary cell wall (SCW) biosynthesis is the biological process that generates wood, an important renewable feedstock for materials and energy. NAC domain transcription factors, particularly Vascular-Related NAC-Domain (VND) and Secondary Wall-Associated NAC Domain (SND) proteins, are known to regulate SCW differentiation. The regulation of VND and SND is important to maintain homeostasis for plants to avoid abnormal growth and development. We previously identified a splice variant, PtrSND1-A2IR, derived from PtrSND1-A2 as a dominant-negative regulator, which suppresses the transactivation of all PtrSND1 family members. PtrSND1-A2IR also suppresses the self-activation of the PtrSND1 family members except for its cognate transcription factor, PtrSND1-A2, suggesting the existence of an unknown factor needed to regulate PtrSND1-A2. Here, a splice variant, PtrVND6-C1IR, derived from PtrVND6-C1 was discovered that suppresses the protein functions of all PtrVND6 family members. PtrVND6-C1IR also suppresses the expression of all PtrSND1 members, including PtrSND1-A2, demonstrating that PtrVND6-C1IR is the previously unidentified regulator of PtrSND1-A2. We also found that PtrVND6-C1IR cannot suppress the expression of its cognate transcription factor, PtrVND6-C1. PtrVND6-C1 is suppressed by PtrSND1-A2IR. Both PtrVND6-C1IR and PtrSND1-A2IR cannot suppress their cognate transcription factors but can suppress all members of the other family. The results indicate that the splice variants from the PtrVND6 and PtrSND1 family may exert reciprocal cross-regulation for complete transcriptional regulation of these two families in wood formation. This reciprocal cross-regulation between families suggests a general mechanism among NAC domain proteins and likely other transcription factors, where intron-retained splice variants provide an additional level of regulation.

2019 ◽  
Vol 70 (12) ◽  
pp. 3111-3123 ◽  
Author(s):  
Lili Xiang ◽  
Xiaofen Liu ◽  
Heng Li ◽  
Xueren Yin ◽  
Donald Grierson ◽  
...  

Abstract ‘Jimba’, a well-known white flowered chrysanthemum cultivar, occasionally and spontaneously produces red colored petals under natural cultivation, but there is little information about the molecular regulatory mechanism underlying this process. We analysed the expression patterns of 91 MYB transcription factors in ‘Jimba’ and ‘Turning red Jimba’ and identified an R3 MYB, CmMYB#7, whose expression was significantly decreased in ‘Turning red Jimba’ compared with ‘Jimba’, and confirmed it is a passive repressor of anthocyanin biosynthesis. CmMYB#7 competed with CmMYB6, which together with CmbHLH2 is an essential component of the anthocyanin activation complex, for interaction with CmbHLH2 through the bHLH binding site in the R3 MYB domain. This reduced binding of the CmMYB6–CmbHLH2 complex and inhibited its ability to activate CmDFR and CmUFGT promoters. Moreover, using transient expression assays we demonstrated that changes in the expression of CmMYB#7 accounted for alterations in anthocyanin content. Taken together, our findings illustrate that CmMYB#7 is a negative regulator of anthocyanin biosynthesis in chrysanthemum.


2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Joachim Altschmied ◽  
Nicole Büchner ◽  
Sascha Jakob ◽  
Sabrina Farrokh ◽  
Christine Goy ◽  
...  

Grainyhead-like 3 (GRHL3) is a member of the evolutionary conserved Grainyhead family of transcription factors. In humans, three isoforms are derived from differential first exon usage and alternative splicing, which differ only in their N-terminus. Isoform 2, the only variant also present in mouse, is required for endothelial cell (EC) migration and protects against apoptosis. The functions of the human specific isoforms 1 and 3, which are derived from an alternatively spliced pre-mRNA, have not yet been investigated, although all three isoforms are expressed in EC. Therefore, we have assessed their effects on EC migration and apoptosis. Overexpression of the two proteins had opposite effects on EC migration, with isoform 1 acting pro-migratory. This protein also protected EC against apoptosis in an eNOS-dependent manner, whereas isoform 3 had no effect. These opposing outcomes with respect to apoptosis EC were corroborated by isoform-specific knockdowns. With reporter assays using a GRHL3-specific luciferase reporter we demonstrated that both are active transcription factors. Microarray analyses revealed that they induce divergent target gene sets in EC. Two validated targets, Akt2 and Mxi1, which are upregulated by isoform1, are regulators of Akt1-, and thus eNOS-phosphorylation and apoptosis, which could explain the effects of this protein on these processes. In vivo, overexpression of isoform 3 in zebrafish embryos resulted in increased lethality and severe deformations, while isoform 1 had no deleterious effect. In conclusion, our data demonstrate that the splice variant derived isoforms 1 and 3 of the human transcription factor GRHL3 induce opposing effects in primary human endothelial cells and in a whole animal model, most likely through the induction of different target genes.


1996 ◽  
Vol 271 (22) ◽  
pp. 13221-13227 ◽  
Author(s):  
Eric Caldenhoven ◽  
Thamar B. van Dijk ◽  
Roberto Solari ◽  
John Armstrong ◽  
Jan A. M. Raaijmakers ◽  
...  

2010 ◽  
Vol 38 (1) ◽  
pp. 223-228 ◽  
Author(s):  
Simon S. McDade ◽  
Dennis J. McCance

The p53 family of transcription factors is made up of p53, p63 and p73, which share significant structural homology. In particular, transcriptional complexity and the expression of multiple protein isoforms are an emergent trait of all family members. p63 is the evolutionarily eldest member of the p53 family and the various isoforms have critical roles in the development of stratifying epithelia. Recent results have uncovered additional splice variants, adding to the complexity of the transcriptional architecture of p63. These observations and the emerging extensive interplay between p63 and p53 in development, proliferation and differentiation underline the importance of considering all isoforms and family members in studies of the function of p53 family members.


2021 ◽  
Vol 22 (17) ◽  
pp. 9275
Author(s):  
Nuo Shen ◽  
Sifan Hou ◽  
Guoqing Tu ◽  
Wenzhi Lan ◽  
Yanping Jing

The remodeling of root architecture is regarded as a major development to improve the plant’s adaptivity to phosphate (Pi)-deficient conditions. The WRKY transcription factors family has been reported to regulate the Pi-deficiency-induced systemic responses by affecting Pi absorption or transportation. Whether these transcription factors act as a regulator to mediate the Pi-deficiency-induced remodeling of root architecture, a typical local response, is still unclear. Here, we identified an Arabidopsis transcription factor, WRKY33, that acted as a negative regulator to mediate the Pi-deficiency-induced remodeling of root architecture. The disruption of WRKY33 in wrky33-2 mutant increased the plant’s low Pi sensitivity by further inhibiting the primary root growth and promoting the formation of root hair. Furthermore, we revealed that WRKY33 negatively regulated the remodeling of root architecture by controlling the transcriptional expression of ALMT1 under Pi-deficient conditions, which further mediated the Fe3+ accumulation in root tips to inhibit the root growth. In conclusion, this study demonstrates a previously unrecognized signaling crosstalk between WRKY33 and the ALMT1-mediated malate transport system to regulate the Pi deficiency responses.


2018 ◽  
Author(s):  
Gregory J. Fonseca ◽  
Jenhan Tao ◽  
Emma M. Westin ◽  
Sascha H. Duttke ◽  
Nathanael J. Spann ◽  
...  

ABSTRACTMechanisms by which members of the AP-1 family of transcription factors play both redundant and non-redundant biological roles despite recognizing the same DNA sequence remain poorly understood. To address this question, we investigated the molecular functions and genome-wide DNA binding patterns of AP-1 family members in macrophages. ChIP-sequencing showed overlapping and distinct binding profiles for each factor that were remodeled following TLR4 ligation. Development of a machine learning approach that jointly weighs hundreds of DNA recognition elements yielded dozens of motifs predicted to drive factor-specific binding profiles. Machine learning-based predictions were confirmed by analysis of the effects of mutations in genetically diverse mice and by loss of function experiments. These findings provide evidence that non-redundant genomic locations of different AP-1 family members in macrophages largely result from collaborative interactions with diverse, locus-specific ensembles of transcription factors and suggest a general mechanism for encoding functional specificities of their common recognition motif.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3750-3750
Author(s):  
Yun Tan ◽  
Wen Jin ◽  
Kang Wu ◽  
Kankan Wang

Abstract Acute myeloid leukemia (AML) is often accompanied with the aberrant expression of transcription factors. In t(8;21) AML, the AML1-ETO fusion protein executes its critical role in leukemogenesis through the interference with hematopoietic transcription factors (TFs) including AML1, C/EBPα, PU.1 and c-Myb. These transcription factors cooperate to modulate hematopoiesis by regulating their differentiation-related target genes. In our previous work, we have identified that AML1-ETO suppresses the AML1-dependent transactivation of the gene encoding the neutrophil granule protease, cathepsin G (CTSG). However, the detailed mechanisms of AML1-ETO mediated transrepression, especially coordinated regulation of hematopoietic transcription factors, have not been characterized yet. To investigate the regulatory pattern of CTSG by hematopoietic specific transcription factors, we constructed a luciferase reporter containing the CTSG promoter and co-transfect it with AML1, c-Myb, C/EBPα or PU.1 to 293T cells. The results of luciferase assays showed that these TFs individually activated the CTSG promoter, and synergistic transactivation occurred between AML1 and c-Myb, C/EBPα and PU.1, and PU.1 and c-Myb on the CTSG promoter. Furthermore, AML1/ETO effectively suppressed the transcription factor-dependent transactivation and synergistic transactivation of the CTSG promoter. Chromatin immunoprecipitation assays further demonstrated that AML1-ETO coexisted with these TFs on the CTSG promoter in AML1/ETO-positive Kasumi-1 cell line, indicating AML1-ETO was tethered to the chromatin bound by these TFs. The data suggested that AML1-ETO might act as a negative regulator by interfering the normal function of hematopoietic TFs instead of competing for their binding. In addition, to reveal the underlying mechanism of AML1/ETO-mediated transcription repression at the epigenetic level, we examined the epigenetic status of the CTSG promoter in AML1-ETO negative and positive cells, and found the level of histone H3 Lys9 acetylation on the CTSG promoter was obviously lower in AML1-ETO positive cells than that in AML1-ETO negative cells. The data suggested that AML1-ETO might repress the gene transcription by changing the H3 acetylation status of its target gene. Collectively, our findings demonstrate that AML1-ETO represses the transactivation of the CTSG promoter mediated by multiple hematopoietic transcription factors through a decrease of H3 acetylation. Disclosures: No relevant conflicts of interest to declare.


2001 ◽  
Vol 276 (50) ◽  
pp. 47013-47020 ◽  
Author(s):  
Mary J. Wagner ◽  
Markéta Gogela-Spehar ◽  
Rachel C. Skirrow ◽  
Randal N. Johnston ◽  
Karl Riabowol ◽  
...  

The candidate tumor suppressor gene,ING1, encodes several protein isoforms as a result of alternative splicing that may possess agonistic and antagonistic roles in the control of cell proliferation and apoptosis. Recently a related gene,ING2, was isolated in human whose expression is increased in adenocarcinomas. Little is known about the cellular function and regulation of these ING family members, but the fact that ING proteins contain a plant homeodomain finger suggests that these proteins may modulate transcription factor-mediated pathways. To elucidate how ING may interact in different tissues to modulate function, we used amphibian metamorphosis as a model system in which a single stimulus, thyroid hormone (TH), initiates tissue-specific proliferation, differentiation, and apoptosis. We have isolated the firstXenopus laevis ING2and demonstrate that transcript levels increase in response to TH treatment. We provide evidence for the existence of splice variants that are differentially expressed in tissues with different TH-induced fates. Western blots using an antibody directed against the highly conserved C-terminal end of ING proteins reveal a tissue-specific pattern of ING isoform expression in adultXenopustissues. Analyses of premetamorphic tadpole tissues show a TH-induced accumulation of ING proteins in tail, whereas the levels in the leg are not affected. This TH-induced accumulation is also observed in serum-free tail organ cultures and is prevented by inhibitors of tail apoptosis. Therefore, this work presents the first link between ING expression and a hormonally regulated nuclear transcription factor-mediated apoptotic response opening the possibility that ING family members may be involved in transducing the signal initiated by TH that determines cell fate.


2014 ◽  
Vol 42 (15) ◽  
pp. 9753-9760 ◽  
Author(s):  
Cai Chen ◽  
Ralf Bundschuh

Abstract Binding of transcription factors to their binding sites in promoter regions is the fundamental event in transcriptional gene regulation. When a transcription factor binding site is located within a nucleosome, the DNA has to partially unwrap from the nucleosome to allow transcription factor binding. This reduces the rate of transcription factor binding and is a known mechanism for regulation of gene expression via chromatin structure. Recently a second mechanism has been reported where transcription factor off-rates are dramatically increased when binding to target sites within the nucleosome. There are two possible explanations for such an increase in off-rate short of an active role of the nucleosome in pushing the transcription factor off the DNA: (i) for dimeric transcription factors the nucleosome can change the equilibrium between monomeric and dimeric binding or (ii) the nucleosome can change the equilibrium between specific and non-specific binding to the DNA. We explicitly model both scenarios and find that dimeric binding can explain a large increase in off-rate while the non-specific binding model cannot be reconciled with the large, experimentally observed increase. Our results suggest a general mechanism how nucleosomes increase transcription factor dissociation to promote exchange of transcription factors and regulate gene expression.


Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1437
Author(s):  
Gianmarco Stati ◽  
Francesca Passaretta ◽  
Florelle Gindraux ◽  
Lucia Centurione ◽  
Roberta Di Pietro

In the framework of space flight, the risk of radiation carcinogenesis is considered a “red” risk due to the high likelihood of occurrence as well as the high potential impact on the quality of life in terms of disease-free survival after space missions. The cyclic AMP response element-binding protein (CREB) is overexpressed both in haematological malignancies and solid tumours and its expression and function are modulated following irradiation. The CREB protein is a transcription factor and member of the CREB/activating transcription factor (ATF) family. As such, it has an essential role in a wide range of cell processes, including cell survival, proliferation, and differentiation. Among the CREB-related nuclear transcription factors, NF-κB and p53 have a relevant role in cell response to ionising radiation. Their expression and function can decide the fate of the cell by choosing between death or survival. The aim of this review was to define the role of the CREB/ATF family members and the related transcription factors in the response to ionising radiation of human haematological malignancies and solid tumours.


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