scholarly journals The α-Gliadins in Bread Wheat: Effect of Nitrogen Treatment on the Expression of the Major Celiac Disease Immunogenic Complex in Two RNAi Low-Gliadin Lines

2021 ◽  
Vol 12 ◽  
Author(s):  
Susana Sánchez-León ◽  
María José Giménez ◽  
Francisco Barro

Celiac Disease (CD) is an autoimmune disorder that affects approximately 1% of the worldwide population. The α-gliadins of wheat contain the 33-mer peptide, the most active peptide in CD both in adults and pediatric patients. In this study, we have characterized the variants and expression profile of an α-gliadins amplicon, harboring the 33-mer peptide, in two low-gliadin RNAi wheat lines, under two different Nitrogen (N) treatments. We estimated that the amplicon expands 45 different α-gliadin variants with high variability due to length, randomly distributed SNPs, and the presence of encoded CD epitopes. Expression of this amplicon is reduced in both RNAi lines in comparison to the wild type. High N treatment significantly increases transcripts of the amplicon in the wild type, but not in the transgenic lines. Classification of α-gliadin variants, considering the number of epitopes, revealed that amplicon variants containing the full complement of 33-mer peptide were affected by N treatment, increasing their expression when N was increased. Line D793 provided higher and more stable silencing through different N fertilization regimes, expressing fewer CD epitopes than D783. Results of this study are important for better understanding of RNAi α-gliadin silencing in response to N treatments, and for undertaking new strategies by RNAi or CRISPR/Cas toward obtaining new varieties suitable for people suffering gluten intolerances.

2019 ◽  
Author(s):  
Chao Cheng ◽  
Shutong Hu ◽  
Yun Han ◽  
Di Xia ◽  
Bang-Lian Huang ◽  
...  

Abstract In this study we cloned a WRI1-like gene from yellow nutsedge. Conserved domain and phylogenetic analyses indicated it to be a WRI3/4-like gene. Arabidopsis plants transformed with WRI3/4-like gene showed significantly improved tolerance to both PEG-simulated drought stress and real dehydration compared with the wild type. Quantitative RT-PCR indicated that, under unstressed conditions, the expressions of key genes involved in fatty acid biosynthesis was not significantly different between wild type (WT) and transgenic lines, while the expressions of genes involved in cuticular wax biosynthesis was significantly higher in transgenic lines compared with the wild type. The PEG treatment slightly decreased the expression of above mentioned genes in WT plants while it was significantly increased in transgenic lines compared with their respective unstressed control. Without PEG treatment, the expression of TAG1, the gene involved in triacylglycerol (TAG) accumulation, was 10-40% lower in the transgenic lines than that in the wild type. However, after PEG treatment, the expression of TAG1 was slightly decreased in the wild type, while in the transgenic lines its expression was decreased by 20-70% compared with unstressed transgenic lines and was highly significantly lower than that in the wild type. The cuticular wax content in Arabidopsis leaves was significantly higher in the transgenic lines than that in the wild type, while the oil content was not significantly different.


1991 ◽  
Vol 11 (8) ◽  
pp. 3931-3939
Author(s):  
B Repetto ◽  
A Tzagoloff

The assembly of alpha-ketoglutarate dehydrogenase complex (KGDC) has been studied in wild-type Saccharomyces cerevisiae and in respiratory-deficient strains (pet) with mutations in KGD1 and KGD2, the structural genes for alpha-ketoglutarate dehydrogenase (KE1) and dihydrolipoyl transsuccinylase (KE2) components, respectively. Mutants unable to express KE1 or KE2 form partial complexes similar to those reported in earlier studies on the resolution and reconstitution of bacterial and mammalian KGDC. Thus mutants lacking KE1 assemble a high-molecular-weight subcomplex consisting of a KE2 core particle with bound dihydrolipoyl dehydrogenase (E3). Similarly, mitochondrial extracts of mutants lacking KE2 contain dimeric KE1 and E3. These components, however, are not associated with each other. The partial complexes detected in the mutants are capable of reconstituting normal KGDC when supplied with the missing subunit. Complete restoration of overall alpha-ketoglutarate dehydrogenase activity is achieved by mixing appropriate ratios of mitochondrial extracts from mutants deficient in KE1 and KE2. The reconstitution of enzymatic activity correlates with binding of KE1 to the KE2-E3 particle to form a complex with the same sedimentation properties as wild-type KGDC. Overexpression of KE2 relative to KE1 results in a preponderance of incompletely assembled complexes with substoichiometric contents of KE1. Formation of a complex with a full complement of KE1 therefore depends on a balanced output of KE1 and KE2 from their respective genes. Biochemical screens of a pet mutant collection have led to the identification of a new gene required for the expression of enzymatically active KGDC. Mitochondria of the mutant have all of the catalytic subunits of KGDC. Sedimentation analysis of these components indicates that while the mutant has a stable KE2-E3 subcomplex, the interaction of KE1 with KE2 core is much weaker in the mutant than in the wild type. The gene product responsible for this phenotype, therefore, appears to function at a late stage of assembly of KGDC, most likely by posttranslational modification of one of the subunits.


1991 ◽  
Vol 11 (8) ◽  
pp. 3931-3939 ◽  
Author(s):  
B Repetto ◽  
A Tzagoloff

The assembly of alpha-ketoglutarate dehydrogenase complex (KGDC) has been studied in wild-type Saccharomyces cerevisiae and in respiratory-deficient strains (pet) with mutations in KGD1 and KGD2, the structural genes for alpha-ketoglutarate dehydrogenase (KE1) and dihydrolipoyl transsuccinylase (KE2) components, respectively. Mutants unable to express KE1 or KE2 form partial complexes similar to those reported in earlier studies on the resolution and reconstitution of bacterial and mammalian KGDC. Thus mutants lacking KE1 assemble a high-molecular-weight subcomplex consisting of a KE2 core particle with bound dihydrolipoyl dehydrogenase (E3). Similarly, mitochondrial extracts of mutants lacking KE2 contain dimeric KE1 and E3. These components, however, are not associated with each other. The partial complexes detected in the mutants are capable of reconstituting normal KGDC when supplied with the missing subunit. Complete restoration of overall alpha-ketoglutarate dehydrogenase activity is achieved by mixing appropriate ratios of mitochondrial extracts from mutants deficient in KE1 and KE2. The reconstitution of enzymatic activity correlates with binding of KE1 to the KE2-E3 particle to form a complex with the same sedimentation properties as wild-type KGDC. Overexpression of KE2 relative to KE1 results in a preponderance of incompletely assembled complexes with substoichiometric contents of KE1. Formation of a complex with a full complement of KE1 therefore depends on a balanced output of KE1 and KE2 from their respective genes. Biochemical screens of a pet mutant collection have led to the identification of a new gene required for the expression of enzymatically active KGDC. Mitochondria of the mutant have all of the catalytic subunits of KGDC. Sedimentation analysis of these components indicates that while the mutant has a stable KE2-E3 subcomplex, the interaction of KE1 with KE2 core is much weaker in the mutant than in the wild type. The gene product responsible for this phenotype, therefore, appears to function at a late stage of assembly of KGDC, most likely by posttranslational modification of one of the subunits.


Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 374
Author(s):  
Jiangshan Cong ◽  
Cuicui Tao ◽  
Xuan Zhang ◽  
Hui Zhang ◽  
Tingcai Cheng ◽  
...  

Bombyx mori silk protein genes are strictly turned on and off in different developmental stages under the hormone periodically change. The broad complex (BrC) is a transcription factor mediating 20-hydroxyecdysone action, which plays important roles during metamorphosis. Here, we observed that two isoforms of BmBrC (BmBrC-Z2 and BmBrC-Z4) exhibited contrasting expression patterns with fibroin genes (FibH, FibL and P25) in the posterior silk gland (PSG), suggesting that BmBrC may negatively regulate fibroin genes. Transgenic lines were constructed to ectopically overexpress BmBrC-Z2 in the PSG. The silk protein genes in the transgenic line were decreased to almost half of that in the wild type. The silk yield was decreased significantly. In addition, the expression levels of regulatory factors (BmKr-h1 and BmDimm) response to juvenile hormone (JH) signal were inhibited significantly. Then exogenous JH in the BmBrC-Z2 overexpressed lines can inhibit the expression of BmBrC-Z2 and activate the expression of silk protein genes and restore the silk yield to the level of the wild type. These results indicated that BmBrC may inhibit fibroin genes by repressing the JH signal pathway, which would assist in deciphering the comprehensive regulation mechanism of silk protein genes.


2021 ◽  
Author(s):  
Jérôme Cortot ◽  
Jean-Pierre Farine ◽  
Jean-François Ferveur ◽  
Claude Everaerts

Abstract The cuticle of all insects is covered with hydrocarbons which have multiple functions. Cuticular hydrocarbons (CHCs) basically serve to protect insects against environmental harm and to reduce dehydration. In many species, some CHCs also act as pheromones. CHCs have been intensively studied in Drosophila species and more specially in D. melanogaster. In this species, flies produce about 40 CHCs forming a complex sex- and species-specific bouquet. The quantitative and qualitative pattern of the CHC bouquet was characterized during the first days of adult life but remains unexplored in aging flies. Here, we characterized CHCs during the whole—or a large period of—adult life in males and females of several wild type and transgenic lines. Both types of lines included standard and variant CHC profiles. Some of the genotypes tested here showed very dramatic and unexpected aging-related variation based on their early days profile. This study provides a concrete dataset to better understand the mechanisms underlying the establishment and maintenance of CHCs on the fly cuticle. It could be useful to determine physiological parameters, including age and response to climate variation, in insects collected in the wild.


2021 ◽  
Author(s):  
Ge Bai ◽  
Yong Li ◽  
Da-Hai Yang ◽  
Tao Pang ◽  
Zhi-Yong Fan ◽  
...  

Nicotine is one of the most important secondary metabolites in tobacco, and its biosynthesis can be induced by topping and jasmonic acid treatment. NtMYC2s play pivotal roles in the regulation of nicotine. The mediator server as a bridge betwen the transcription factors and RNA polymerase in order to facilitates transcription and functions in plants. However, the role of mediator in the regulation of nicotine biosynthesis remains unknown. In this study, we firstly identify the NtMED25 through homologous analysis. NtMED25 interacts with NtMYC2s through the MD region. Interestingly, the nicotine content is decreased in the the knock-down transgenic lines of NtMED25, and the expression levels of two nicotine biosynthesis genes, NtQPT2 and NtPMT2, are also reduced when compared with that in the wild-type plants. Furthermore, NtMED25 enhances the binding of NtMYC2a/ NtMYC2b to the promoter of NtPMT2 and NtQPT2, and then facilitates the nicotine biosynthesis. Therefore, our study revealed the function of mediator in the regulation of nicotine, and provide the insight role on the transcriptional regulation of plant secondary metabolites.


Author(s):  
Thecan Caesar-Ton That ◽  
Lynn Epstein

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.


2007 ◽  
Vol 28 (3) ◽  
pp. 897-906 ◽  
Author(s):  
Thomas J. Pohl ◽  
Jac A. Nickoloff

ABSTRACT Homologous recombination (HR) is critical for DNA double-strand break (DSB) repair and genome stabilization. In yeast, HR is catalyzed by the Rad51 strand transferase and its “mediators,” including the Rad52 single-strand DNA-annealing protein, two Rad51 paralogs (Rad55 and Rad57), and Rad54. A Rad51 homolog, Dmc1, is important for meiotic HR. In wild-type cells, most DSB repair results in gene conversion, a conservative HR outcome. Because Rad51 plays a central role in the homology search and strand invasion steps, DSBs either are not repaired or are repaired by nonconservative single-strand annealing or break-induced replication mechanisms in rad51Δ mutants. Although DSB repair by gene conversion in the absence of Rad51 has been reported for ectopic HR events (e.g., inverted repeats or between plasmids), Rad51 has been thought to be essential for DSB repair by conservative interchromosomal (allelic) gene conversion. Here, we demonstrate that DSBs stimulate gene conversion between homologous chromosomes (allelic conversion) by >30-fold in a rad51Δ mutant. We show that Rad51-independent allelic conversion and break-induced replication occur independently of Rad55, Rad57, and Dmc1 but require Rad52. Unlike DSB-induced events, spontaneous allelic conversion was detected in both rad51Δ and rad52Δ mutants, but not in a rad51Δ rad52Δ double mutant. The frequencies of crossovers associated with DSB-induced gene conversion were similar in the wild type and the rad51Δ mutant, but discontinuous conversion tracts were fivefold more frequent and tract lengths were more widely distributed in the rad51Δ mutant, indicating that heteroduplex DNA has an altered structure, or is processed differently, in the absence of Rad51.


Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Yasumasa Tsukamoto ◽  
Jun-ichi Kato ◽  
Hideo Ikeda

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 618
Author(s):  
Yue Jin ◽  
Shihao Li ◽  
Yang Yu ◽  
Chengsong Zhang ◽  
Xiaojun Zhang ◽  
...  

A mutant of the ridgetail white prawn, which exhibited rare orange-red body color with a higher level of free astaxanthin (ASTX) concentration than that in the wild-type prawn, was obtained in our lab. In order to understand the underlying mechanism for the existence of a high level of free astaxanthin, transcriptome analysis was performed to identify the differentially expressed genes (DEGs) between the mutant and wild-type prawns. A total of 78,224 unigenes were obtained, and 1863 were identified as DEGs, in which 902 unigenes showed higher expression levels, while 961 unigenes presented lower expression levels in the mutant in comparison with the wild-type prawns. Based on Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis, as well as further investigation of annotated DEGs, we found that the biological processes related to astaxanthin binding, transport, and metabolism presented significant differences between the mutant and the wild-type prawns. Some genes related to these processes, including crustacyanin, apolipoprotein D (ApoD), cathepsin, and cuticle proteins, were identified as DEGs between the two types of prawns. These data may provide important information for us to understand the molecular mechanism of the existence of a high level of free astaxanthin in the prawn.


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