scholarly journals The Flowering Repressor SVP recruits the TOPLESS co-repressor to control flowering in chrysanthemum and Arabidopsis

2021 ◽  
Author(s):  
Jiafu Jiang ◽  
Zixin Zhang ◽  
Qian Hu ◽  
Yuqing Zhu ◽  
Zheng Gao ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Dominant Negative ◽  
Mads Box ◽  
Loss Of Function ◽  
Vegetative Phase ◽  
Dominant Negative Mutation ◽  
Plant Life ◽  
Mads Box Gene ◽  
Floral Repressor ◽  
Transcriptional Complex

Plant flowering time is a consequence of the perception of environmental and endogenous signals. The MCM1-AGAMOUSDEFICIENS-SRF-box (MADS-box) gene SHORT VEGETATIVE PHASE (SVP) is a pivotal repressor that negatively regulates the floral transition during the vegetative phase. The transcriptional corepressor TOPLESS (TPL) plays critical roles in many aspects of plant life. An interaction first identified between the second LXLXLX motif (LRLGLP) of CmSVP with CmTPL1-2, which can repress the expression of a key flowering factor CmFTL3 by binding its promotor CArG element in chrysanthemum. Genetic analysis suggested that the CmSVP-CmTPL1-2 transcriptional complex is a prerequisite for SVP to act as a floral repressor, which reduces CmFTL3 transcriptional activity. CmSVP rescued the phenotype of the svp-31 mutant in Arabidopsis, and overexpression of AtSVP or CmSVP in the Arabidopsis dominant negative mutation tpl-1 led to a loss-of-function in late flowering, which confirmed the highly conserved function of SVP in the two completely different species. Thus, we have validated a conserved machinery wherein SVP relies on TPL to inhibit flowering through the direct regulation of FT, which is more meaningful for the evolution of species and could be translated to high-quality cultivation and breeding of crops.

scholarly journals Natural and induced loss of function mutations in SlMBP21 MADS-box gene led to jointless-2 phenotype in tomato

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Maria Victoria Gomez Roldan ◽  
Claire Périlleux ◽  
Halima Morin ◽  
Samuel Huerga-Fernandez ◽  
David Latrasse ◽  
...  
Keyword(s):  
Mads Box ◽  
Loss Of Function ◽  
Mads Box Gene

scholarly journals A Novel, C-Terminal Dominant Negative Mutation of the GR Causes Familial Glucocorticoid Resistance through Abnormal Interactions with p160 Steroid Receptor Coactivators

2002 ◽  
Vol 87 (6) ◽  
pp. 2658-2667 ◽  
Author(s):  
Alessandra Vottero ◽  
Tomoshige Kino ◽  
Herve Combe ◽  
Pierre Lecomte ◽  
George P. Chrousos
Keyword(s):  
Ligand Binding ◽  
Transcriptional Activity ◽  
Fluorescent Protein ◽  
Dominant Negative ◽  
Glucocorticoid Resistance ◽  
Base Substitution ◽  
Wild Type ◽  
Nuclear Speckles ◽  
Dominant Negative Mutation ◽  
Type Receptor

Primary cortisol resistance is a rare, inherited or sporadic form of generalized end-organ insensitivity to glucocorticoids. Here, we report a kindred in which affected members had a heterozygous T to G base substitution at nucleotide 2373 of exon 9α of the GR gene, causing substitution of Ile by Met at position 747. This mutation was located close to helix 12, at the C terminus of the ligand-binding domain, which has a pivotal role in the formation of activation function (AF)-2, a subdomain that interacts with p160 coactivators. The affinity of the mutant GR for dexamethasone was decreased by about 2-fold, and its transcriptional activity on the glucocorticoid-responsive mouse mammary tumor virus promoter was compromised by 20- to 30-fold. In addition, the mutant GR functioned as a dominant negative inhibitor of wild-type receptor-induced transactivation. The mutant GR through its intact AF-1 domain bound to a p160 coactivator, but failed to do so through its AF-2 domain. Overexpression of a p160 coactivator restored the transcriptional activity and reversed the negative transdominant activity of the mutant GR. Interestingly, green fluorescent protein (GFP)-fused GRαI747M had a slight delay in its translocation from the cytoplasm into the nucleus and formed coarser nuclear speckles than GFP-fused wild-type GRα. Similarly, a GFP-fused p160 coactivator had a distinctly different distribution in the nucleus in the presence of mutant vs. wild-type receptor, presenting also as coarser speckling. We conclude that the mutation at amino acid 747 of the GR causes familial, autosomal dominant glucocorticoid resistance by decreasing ligand binding affinity and transcriptional activity, and by exerting a negative transdominant effect on the wild-type receptor. The mutant receptor has an ineffective AF-2 domain, which leads to an abnormal interaction with p160 coactivators and a distinct nuclear distribution of both.

scholarly journals The new kid on the block: A dominant-negative mutation of phototropin1 enhances carotenoid content in tomato fruits

2020 ◽  
Author(s):  
Himabindu Vasuki Kilambi ◽  
Alekhya Dindu ◽  
Kapil Sharma ◽  
Narasimha Rao Nizampatnam ◽  
Neha Gupta ◽  
...  
Keyword(s):  
Protein Quality ◽  
Causal Link ◽  
Dominant Negative ◽  
Carotenoid Content ◽  
Loss Of Function ◽  
Tomato Fruits ◽  
Dominant Negative Mutation ◽  
Volatile Profiles ◽  
Developmental Responses ◽  
Potential Tool

AbstractPhototropins, the UVA-blue light photoreceptors, endow plants to detect the direction of light and optimize photosynthesis by regulating chloroplasts positioning and stomatal gas exchange. Little is known about their functions in other developmental responses. A tomato Non-phototropic seedling1 (Nps1) mutant, bearing an Arg495His substitution in the vicinity of LOV2 domain in phototropin1, dominant-negatively blocks phot1 and phot2 responses. The fruits of Nps1 mutant were enriched in carotenoids, particularly lycopene, than its parent, Ailsa Craig. Contrarily, CRISPR/CAS9-edited loss of function phototropin1 mutants displayed subdued carotenoids than the parent. The enrichment of carotenoids in Nps1 fruits is genetically linked with the mutation and exerted in a dominant-negative fashion. Nps1 also altered volatile profiles with high levels of lycopene-derived 6-methyl 5-hepten2-one. The transcript levels of several MEP and carotenogenesis pathways genes were upregulated in Nps1. Nps1 fruits showed altered hormonal profiles with subdued ethylene emission and reduced respiration. Proteome profiles showed a causal link between higher carotenogenesis and increased levels of protein protection machinery, which may stabilize proteins contributing to MEP and carotenogenesis pathways. Given the enhancement of carotenoid content by Nps1 in a dominant-negative fashion, it offers a potential tool for high lycopene-bearing hybrid tomatoes.One-sentence summaryA dominant-negative phototropin1 mutation enhances carotenoid levels, alters metabolite homeostasis, and protein quality control machinery in tomato fruits.

scholarly journals Bracteomania, an inflorescence anomaly, is caused by the loss of function of the MADS-box gene squamosa in Antirrhinum majus.

1992 ◽  
Vol 11 (4) ◽  
pp. 1239-1249 ◽  
Author(s):  
P. Huijser ◽  
J. Klein ◽  
W.E. Lönnig ◽  
H. Meijer ◽  
H. Saedler ◽  
...  
Keyword(s):  
Antirrhinum Majus ◽  
Mads Box ◽  
Loss Of Function ◽  
Mads Box Gene

scholarly journals Ectopic Expression of the Petunia MADS Box Gene UNSHAVEN Accelerates Flowering and Confers Leaf-Like Characteristics to Floral Organs in a Dominant-Negative Manner

2004 ◽  
Vol 16 (6) ◽  
pp. 1490-1505 ◽  
Author(s):  
Silvia Ferrario ◽  
Jacqueline Busscher ◽  
John Franken ◽  
Tom Gerats ◽  
Michiel Vandenbussche ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Dominant Negative ◽  
Mads Box ◽  
Floral Organs ◽  
Mads Box Gene
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