scholarly journals Identification and characterization of two closely related histone H4 arginine 3 methyltransferases in Arabidopsis thaliana

2007 ◽  
Vol 408 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Dongsheng Yan ◽  
Yong Zhang ◽  
Lifang Niu ◽  
Yi Yuan ◽  
Xiaofeng Cao
Keyword(s):  
Arabidopsis Thaliana ◽  
Glutathione Transferase ◽  
Fluorescent Protein ◽  
Direct Interaction ◽  
Arginine Methylation ◽  
Site Directed Mutagenesis ◽  
Histone H4 ◽  
Identification And Characterization

Arginine methylation of histone H3 and H4 plays important roles in transcriptional regulation in eukaryotes such as yeasts, fruitflies, nematode worms, fish and mammals; however, less is known in plants. In the present paper, we report the identification and characterization of two Arabidopsis thaliana protein arginine N-methyltransferases, AtPRMT1a and AtPRMT1b, which exhibit high homology with human PRMT1. Both AtPRMT1a and AtPRMT1b methylated histone H4, H2A, and myelin basic protein in vitro. Site-directed mutagenesis of the third arginine (R3) on the N-terminus of histone H4 to lysine (H4R3N) completely abolished the methylation of histone H4. When fused to GFP (green fluorescent protein), both methyltransferases localized to the cytoplasm as well as to the nucleus. Consistent with their subcellular distribution, GST (glutathione transferase) pull-down assays revealed an interaction between the two methyltransferases, suggesting that both proteins may act together in a functional unit. In addition, we demonstrated that AtFib2 (Arabidopsis thaliana fibrillarin 2), an RNA methyltransferase, is a potential substrate for AtPRMT1a and AtPRMT1b, and, furthermore, uncovered a direct interaction between the protein methyltransferase and the RNA methyltransferase. Taken together, our findings implicate AtPRMT1a and AtPRMT1b as H4-R3 protein arginine N-methyltransferases in Arabidopsis and may be involved in diverse biological processes inside and outside the nucleus.

scholarly journals Characterization of PRMT1 from Plasmodium falciparum

2009 ◽  
Vol 421 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Qi Fan ◽  
Jun Miao ◽  
Long Cui ◽  
Liwang Cui
Keyword(s):  
Plasmodium Falciparum ◽  
Fluorescent Protein ◽  
Arginine Methylation ◽  
In Vitro Assays ◽  
Parasite Development ◽  
Type I ◽  
Histone H4 ◽  
Turnover Rates ◽  
Post Translational Modification

Arginine methylation is a post-translational modification that affects many cellular processes in eukaryotes. The malaria parasite Plasmodium falciparum encodes three conserved PRMTs (protein arginine N-methyltransferases). We have determined that PfPRMT1 (P. falciparum PRMT1) has authentic type I PRMT activity to form monomethylarginines and asymmetric dimethylarginines. Compared with mammalian PRMT1s, PfPRMT1 possesses a distinctive N-terminal sequence that is ∼50 amino acids longer and is essential for enzyme activity. Recombinant PfPRMT1 methylated histones H4 and H2A and several conserved substrates involved in RNA metabolism, including fibrillarin, poly(A)-binding protein II, ribosomal protein S2 and a putative splicing factor. Using synthetic peptides and MS, we determined target arginines in several substrates and studied the enzyme kinetics. Whereas the kinetic parameters of recombinant PfPRMT1 on an H4 peptide and S-adenosylmethionine were similar to those of mammalian PRMT1s, PfPRMT1 had much higher substrate-turnover rates. In the histone H4 N-terminus, PfPRMT1 could methylate only Arg3, a mark for transcription activation. Western blotting detected dynamic dimethylation of H4-Arg3 during parasite development, suggesting that histone-arginine methylation may play a conserved role in chromatin-mediated gene regulation. Consistent with the presence of potential substrates in both the cytoplasm and nucleus, green fluorescent protein-tagged PfPRMT1 and untagged PfPRMT1 were localized in both cellular compartments, with the majority in the cytoplasm. in vitro assays showed that PfPRMT1 could be inhibited by several small-molecule inhibitors, with IC50-values in the sub-micromolar range. Most of these compounds also effectively inhibited parasite growth, suggesting that parasite PRMTs are promising targets for developing antiparasitic drugs.

scholarly journals Functional Characterization of the mazEF Toxin-Antitoxin System in the Pathogenic Bacterium Agrobacterium tumefaciens

2021 ◽  
Vol 9 (5) ◽  
pp. 1107
Author(s):  
Wonho Choi ◽  
Yoshihiro Yamaguchi ◽  
Ji-Young Park ◽  
Sang-Hyun Park ◽  
Hyeok-Won Lee ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Physiological Function ◽  
Functional Characterization ◽  
Site Directed Mutagenesis ◽  
In Vitro Assays ◽  
Cell Growth Inhibition ◽  
The Right

Agrobacterium tumefaciens is a pathogen of various plants which transfers its own DNA (T-DNA) to the host plants. It is used for producing genetically modified plants with this ability. To control T-DNA transfer to the right place, toxin-antitoxin (TA) systems of A. tumefaciens were used to control the target site of transfer without any unintentional targeting. Here, we describe a toxin-antitoxin system, Atu0939 (mazE-at) and Atu0940 (mazF-at), in the chromosome of Agrobacterium tumefaciens. The toxin in the TA system has 33.3% identity and 45.5% similarity with MazF in Escherichia coli. The expression of MazF-at caused cell growth inhibition, while cells with MazF-at co-expressed with MazE-at grew normally. In vivo and in vitro assays revealed that MazF-at inhibited protein synthesis by decreasing the cellular mRNA stability. Moreover, the catalytic residue of MazF-at was determined to be the 24th glutamic acid using site-directed mutagenesis. From the results, we concluded that MazF-at is a type II toxin-antitoxin system and a ribosome-independent endoribonuclease. Here, we characterized a TA system in A. tumefaciens whose understanding might help to find its physiological function and to develop further applications.

scholarly journals The Banana Root Endophytome: Differences between Mother Plants and Suckers and Evaluation of Selected Bacteria to Control Fusarium oxysporum f.sp. cubense

2021 ◽  
Vol 7 (3) ◽  
pp. 194
Author(s):  
Carmen Gómez-Lama Cabanás ◽  
Antonio J. Fernández-González ◽  
Martina Cardoni ◽  
Antonio Valverde-Corredor ◽  
Javier López-Cepero ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Canary Islands ◽  
High Throughput Sequencing ◽  
Fungal Communities ◽  
Phenological Stage ◽  
Mother Plants ◽  
Fusarium Wilt Of Banana ◽  
Identification And Characterization

This study aimed to disentangle the structure, composition, and co-occurrence relationships of the banana (cv. Dwarf Cavendish) root endophytome comparing two phenological plant stages: mother plants and suckers. Moreover, a collection of culturable root endophytes (>1000) was also generated from Canary Islands. In vitro antagonism assays against Fusarium oxysporum f.sp. cubense (Foc) races STR4 and TR4 enabled the identification and characterization of potential biocontrol agents (BCA). Eventually, three of them were selected and evaluated against Fusarium wilt of banana (FWB) together with the well-known BCA Pseudomonas simiae PICF7 under controlled conditions. Culturable and non-culturable (high-throughput sequencing) approaches provided concordant information and showed low microbial diversity within the banana root endosphere. Pseudomonas appeared as the dominant genus and seemed to play an important role in the banana root endophytic microbiome according to co-occurrence networks. Fungal communities were dominated by the genera Ophioceras, Cyphellophora, Plecosphaerella, and Fusarium. Overall, significant differences were found between mother plants and suckers, suggesting that the phenological stage determines the recruitment and organization of the endophytic microbiome. While selected native banana endophytes showed clear antagonism against Foc strains, their biocontrol performance against FWB did not improve the outcome observed for a non-indigenous reference BCA (strain PICF7).

scholarly journals Identification and Characterization of Novel Antioxidant Protein Hydrolysates from Kiwicha (Amaranthus caudatus L.)

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 645
Author(s):  
Sergio Montserrat-de la Paz ◽  
Alicia Martinez-Lopez ◽  
Alvaro Villanueva-Lazo ◽  
Justo Pedroche ◽  
Francisco Millan ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Reducing Power ◽  
Protein Isolate ◽  
Protein Hydrolysates ◽  
Antioxidant Peptides ◽  
Amaranthus Caudatus ◽  
Intact Proteins ◽  
Identification And Characterization

Kiwicha (Amaranthus caudatus) is considered one of the few multipurpose pseudocereals for its potential use not only as a source of nutrients and fiber but also for its bioactive compounds. In recent years, antioxidant peptides are commonly used as functional ingredient of food. Herein, a kiwicha protein isolate (KPI), obtained from kiwicha defatted flour (KDF), was hydrolyzed by Bioprotease LA 660, a food-grade endoprotease, under specific conditions. The resulting kiwicha protein hydrolysates (KPHs) were chemically characterized and their digestibility and antioxidant capacity were evaluated by in vitro cell-free experiments owing to their measure of capacity to sequester DPPH free radical and reducing power. KPHs showed higher digestibility and antioxidant capacity than intact proteins into KPI. Therefore, the results shown in this study indicate that KPHs could serve as an adequate source of antioxidant peptides, representing an effective alternative to the generation of functional food.

scholarly journals Identification and Characterization of the Direct Interaction between Methotrexate (MTX) and High-Mobility Group Box 1 (HMGB1) Protein

PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e63073 ◽  
Author(s):  
Yuki Kuroiwa ◽  
Yoichi Takakusagi ◽  
Tomoe Kusayanagi ◽  
Kouji Kuramochi ◽  
Takahiko Imai ◽  
...  
Keyword(s):  
High Mobility ◽  
Direct Interaction ◽  
High Mobility Group ◽  
Hmgb1 Protein ◽  
Identification And Characterization
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