scholarly journals Side chain to main chain hydrogen bonds stabilize a polyglutamine helix in the activation domain of a transcription factor

2018 ◽  
Author(s):  
Albert Escobedo ◽  
Busra Topal ◽  
Micha Ben Achim Kunze ◽  
Juan Aranda ◽  
Giulio Chiesa ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hydrogen Bonds ◽  
Transcriptional Activity ◽  
Main Chain ◽  
Muscular Atrophy ◽  
Helical Structure ◽  
Structural Basis ◽  
Tract Length ◽  
Spinobulbar Muscular Atrophy ◽  
Polyq Tract

Polyglutamine (polyQ) tracts are regions of low sequence complexity of variable length found in more than one hundred human proteins. These tracts are frequent in activation domains of transcription factors and their length often correlates with transcriptional activity. In addition, in nine proteins, tract elongation beyond specific thresholds causes polyQ disorders. To study the structural basis of the association between tract length, transcriptional activity and disease, here we addressed how the conformation of the polyQ tract of the androgen receptor (AR), a transcription factor associated with the polyQ disease spinobulbar muscular atrophy (SBMA), depends on its length. We found that the tract folds into a helical structure stabilized by unconventional hydrogen bonds between glutamine side chains and main chain carbonyl groups. These bonds are bifurcate with the conventional main chain to main chain hydrogen bonds stabilizing α-helices. In addition, since tract elongation provides additional interactions, the helicity of the polyQ tract directly correlates with its length. These findings suggest a plausible rationale for the association between polyQ tract length and AR transcriptional activity and have implications for establishing the mechanistic basis of SBMA.

scholarly journals Side chain to main chain hydrogen bonds stabilize a polyglutamine helix in a transcription factor

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Albert Escobedo ◽  
Busra Topal ◽  
Micha B. A. Kunze ◽  
Juan Aranda ◽  
Giulio Chiesa ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hydrogen Bonds ◽  
Main Chain ◽  
Side Chain

scholarly journals Gene therapy with AR isoform 2 rescues spinal and bulbar muscular atrophy phenotype by modulating AR transcriptional activity

2021 ◽  
Vol 7 (34) ◽  
pp. eabi6896
Author(s):  
Wooi F. Lim ◽  
Mitra Forouhan ◽  
Thomas C. Roberts ◽  
Jesse Dabney ◽  
Ruth Ellerington ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Muscular Atrophy ◽  
Great Promise ◽  
Adeno Associated Virus ◽  
Transcriptional Dysregulation ◽  
Vector Type ◽  
Naturally Occurring ◽  
Targeted Approach ◽  
Polyq Tract

Spinal and bulbar muscular atrophy (SBMA) is an X-linked, adult-onset neuromuscular condition caused by an abnormal polyglutamine (polyQ) tract expansion in androgen receptor (AR) protein. SBMA is a disease with high unmet clinical need. Recent studies have shown that mutant AR-altered transcriptional activity is key to disease pathogenesis. Restoring the transcriptional dysregulation without affecting other AR critical functions holds great promise for the treatment of SBMA and other AR-related conditions; however, how this targeted approach can be achieved and translated into a clinical application remains to be understood. Here, we characterized the role of AR isoform 2, a naturally occurring variant encoding a truncated AR lacking the polyQ-harboring domain, as a regulatory switch of AR genomic functions in androgen-responsive tissues. Delivery of this isoform using a recombinant adeno-associated virus vector type 9 resulted in amelioration of the disease phenotype in SBMA mice by restoring polyQ AR–dysregulated transcriptional activity.

scholarly journals The apple C2H2-type zinc finger transcription factor MdZAT10 positively regulates JA-induced leaf senescence by interacting with MdBT2

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kuo Yang ◽  
Jian-Ping An ◽  
Chong-Yang Li ◽  
Xue-Na Shen ◽  
Ya-Jing Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Transcription Factor ◽  
Liquid Chromatography ◽  
Zinc Finger ◽  
Leaf Senescence ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Liquid Chromatography Mass Spectrometry ◽  
Zinc Finger Transcription Factor ◽  
Insight Into

AbstractJasmonic acid (JA) plays an important role in regulating leaf senescence. However, the molecular mechanisms of leaf senescence in apple (Malus domestica) remain elusive. In this study, we found that MdZAT10, a C2H2-type zinc finger transcription factor (TF) in apple, markedly accelerates leaf senescence and increases the expression of senescence-related genes. To explore how MdZAT10 promotes leaf senescence, we carried out liquid chromatography/mass spectrometry screening. We found that MdABI5 physically interacts with MdZAT10. MdABI5, an important positive regulator of leaf senescence, significantly accelerated leaf senescence in apple. MdZAT10 was found to enhance the transcriptional activity of MdABI5 for MdNYC1 and MdNYE1, thus accelerating leaf senescence. In addition, we found that MdZAT10 expression was induced by methyl jasmonate (MeJA), which accelerated JA-induced leaf senescence. We also found that the JA-responsive protein MdBT2 directly interacts with MdZAT10 and reduces its protein stability through ubiquitination and degradation, thereby delaying MdZAT10-mediated leaf senescence. Taken together, our results provide new insight into the mechanisms by which MdZAT10 positively regulates JA-induced leaf senescence in apple.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals Glycogen Synthase Kinase 3β and Extracellular Signal-Regulated Kinase Inactivate Heat Shock Transcription Factor 1 by Facilitating the Disappearance of Transcriptionally Active Granules after Heat Shock

1998 ◽  
Vol 18 (11) ◽  
pp. 6624-6633 ◽  
Author(s):  
Bin He ◽  
Yong-Hong Meng ◽  
Nahid F. Mivechi
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Transcriptional Activity ◽  
Glycogen Synthase ◽  
Heat Shock Transcription Factor ◽  
Glycogen Synthase Kinase 3Β ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Gsk 3Β ◽  
Transcription Factor 1

ABSTRACT Heat shock transcription factor 1 (HSF-1) activates the transcription of heat shock genes in eukaryotes. Under normal physiological growth conditions, HSF-1 is a monomer. Its transcriptional activity is repressed by constitutive phosphorylation. Upon activation, HSF-1 forms trimers, acquires DNA binding activity, increases transcriptional activity, and appears as punctate granules in the nucleus. In this study, using bromouridine incorporation and confocal laser microscopy, we demonstrated that newly synthesized pre-mRNAs colocalize to the HSF-1 punctate granules after heat shock, suggesting that these granules are sites of transcription. We further present evidence that glycogen synthase kinase 3β (GSK-3β) and extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) participate in the down regulation of HSF-1 transcriptional activity. Transient increases in the expression of GSK-3β facilitate the disappearance of HSF-1 punctate granules and reduce hsp-70 transcription after heat shock. We have also shown that ERK is the priming kinase for GSK-3β. Taken together, these results indicate that GSK-3β and ERK MAPK facilitate the inactivation of activated HSF-1 after heat shock by dispersing HSF-1 from the sites of transcription.

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