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1.
Sci Rep ; 12(1): 20937, 2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36463295

RESUMO

According to molecular profiling studies, a considerable number of patients with pancreatic cancer harbor potentially actionable mutations. However, there are limited relevant data from the Korean population. We assessed the molecular profiles of patients with pancreatic cancer in Korea. This study collected molecular profiling data from patients with pancreatic cancer who visited Seoul National University Bundang Hospital between March 2018 and August 2020. Formalin-fixed, paraffin-embedded tumor specimens were sequenced using a targeted next-generation sequencing (NGS) platform. Cancer-associated mutations were analyzed, and potentially actionable mutations were identified. Potentially actionable mutations were classified into "highly actionable" and "modifies options" based on the Know Your Tumor registry study. In total, 87 patients with NGS tumor panel data were identified. Sixty-one patients (70.1%) had metastatic disease at the time of tissue acquisition. Tissues were obtained from the primary tumors and metastatic sites in 41 (47.1%) and 46 (52.9%) patients, respectively. At least one pathogenic mutation was reported in 86 patients (98.9%). The frequencies of four common mutations in our cohort were similar to those in The Cancer Genome Atlas data. Potentially actionable mutations were identified in 27 patients (31.0%). Of these, mutations categorized as highly actionable and modifies options were identified in 12 (13.8%) and 18 patients (20.7%), respectively. The most frequent highly actionable mutations were located in DNA damage response genes, such as BRCA1, BRCA2, or ATM (n = 6, 6.9%). Two patients with germline BRCA1 mutations received maintenance poly(adenosine diphosphate-ribose) polymerase inhibitor therapy. One patient has been receiving maintenance treatment for 18 months while remaining in radiologically complete remission. Mutational profiles using targeted NGS in Korean patients with pancreatic cancer were similar to those in Western patients. The present study supports the clinical potential and possible expanded clinical use of genetic profiling.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/genética , Mutagênese Sítio-Dirigida , Pentosiltransferases
2.
PLoS One ; 17(12): e0278482, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36454905

RESUMO

Limb Girdle Muscular Dystrophy 2I (LGMDR9) is one of the most common LGMD characterized by defects in glycosylation of α-dystroglycan (matriglycan) resulting from mutations of Fukutin-related protein (FKRP). There is no effective therapy currently available. We recently demonstrated that ribitol supplement increases levels of matriglycan in cells in vitro and in FKRP-P448L (P448L) mutant mouse model through drinking water administration. To be clinically relevant, we have now conducted a dose-escalating efficacy study by gavage in P448L mutant mice. Six months of ribitol treatment daily significantly rescued functions of skeletal, respiratory, and cardiac muscles dose-dependently. This was associated with a dose dependent increase in matriglycan and improvement in muscle pathology with reductions in muscle degeneration, inflammatory infiltration and fibrosis. Importantly, ribitol significantly increased life span and muscle functions of the female animals receiving treatment from 10 months of age. The only observed side effect was gastrointestinal tract bloating with loose stool and this effect is also dose dependent. The results validate the mechanism that ribitol as a pre-substrate of glycosyltransferase is able to compensate for the decreased function of mutant FKRP with restoration of matriglycan expression and provide a guidance for future clinical trial design.


Assuntos
Distrofia Muscular do Cíngulo dos Membros , Fenômenos Fisiológicos Musculoesqueléticos , Feminino , Camundongos , Animais , Ribitol , Longevidade , Modelos Animais de Doenças , Músculos , Pentosiltransferases/genética
3.
Continuum (Minneap Minn) ; 28(6): 1698-1714, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36537976

RESUMO

PURPOSE OF REVIEW: The limb-girdle muscular dystrophies (LGMDs) are a group of inherited muscle disorders with a common feature of limb-girdle pattern of weakness, caused by over 29 individual genes. This article describes the classification scheme, common subtypes, and the management of individuals with LGMD. RECENT FINDINGS: Advances in genetic testing and next-generation sequencing panels containing all of the LGMD genes have led to earlier genetic confirmation, but also to more individuals with variants of uncertain significance. The LGMDs include disorders with autosomal recessive inheritance, which are often due to loss-of-function mutations in muscle structural or repair proteins and typically have younger ages of onset and more rapidly progressive presentations, and those with autosomal dominant inheritance, which can have older ages of presentation and chronic progressive disease courses. All cause progressive disability and potential loss of ability to walk or maintain a job due to progressive muscle wasting. Certain mutations are associated with cardiac or respiratory involvement. No disease-altering therapies have been approved by the US Food and Drug Administration (FDA) for LGMDs and standard treatment uses a multidisciplinary clinic model, but recessive LGMDs are potentially amenable to systemic gene replacement therapies, which are already being tested in clinical trials for sarcoglycan and FKRP mutations. The dominant LGMDs may be amenable to RNA-based therapeutic approaches. SUMMARY: International efforts are underway to better characterize LGMDs, help resolve variants of uncertain significance, provide consistent and improved standards of care, and prepare for future clinical trials.


Assuntos
Distrofia Muscular do Cíngulo dos Membros , Humanos , Distrofia Muscular do Cíngulo dos Membros/diagnóstico , Distrofia Muscular do Cíngulo dos Membros/genética , Distrofia Muscular do Cíngulo dos Membros/terapia , Mutação , Testes Genéticos , Terapia Genética , Instituições de Assistência Ambulatorial , Pentosiltransferases/genética
4.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 39(11): 1205-1210, 2022 Nov 10.
Artigo em Chinês | MEDLINE | ID: mdl-36317204

RESUMO

OBJECTIVE: To analyze the clinical features and genetic variants of three Chinese pedigrees affected with Limb girdle muscular dystrophy type 2I (LGMD2I). METHODS: Clinical data and peripheral blood samples of the three probands and their family members were collected. Whole exome sequencing was carried out for the probands. Candidate variants were verified by Sanger sequencing of their family members. RESULTS: Probands 1 and 2 both featured weakness in the lower limbs. Proband 1 had lost walking ability and had pulmonary ventilation dysfunction. Proband 3 had lower limb pain, palpitations and asthma after exercise. Genetic sequencing revealed that proband 1 harbored compound heterozygous c.545A>G (p.Y182C) and c.1391A>T (p.N464I) variants of the FKRP gene, proband 2 harbored compound heterozygous c.545A>G (p.Y182C) and c.941C>T (p.T314M) variants of the FKRP gene, and proband 3 harbored compound heterozygous c.545A>G (p.Y182C) and c.161G>A (p.R54Q) variants. Among these, the c.161G>A (p.R54Q) variant was unreported previously. CONCLUSION: Compound heterozygous variants of the FKRP gene probably underlay the LGMD2I in the three patients. Whole exome sequencing is crucial for the diagnosis of LGMD2I. The identification of the novel variant also broadened the mutational spectrum of the FKRP gene.


Assuntos
Distrofia Muscular do Cíngulo dos Membros , Pentosiltransferases , Humanos , Linhagem , Pentosiltransferases/genética , Músculo Esquelético , Proteínas/genética , Distrofia Muscular do Cíngulo dos Membros/genética , Mutação , China
5.
Int J Mol Sci ; 23(21)2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36362425

RESUMO

Enzyme-mediated processes have proven to be a valuable and sustainable alternative to traditional chemical methods. In this regard, the use of multi-enzymatic systems enables the realization of complex synthetic schemes, while also introducing a number of additional advantages, including the conversion of reversible reactions into irreversible processes, the partial or complete elimination of product inhibition problems, and the minimization of undesirable by-products. In addition, the immobilization of biocatalysts on magnetic supports allows for easy reusability and streamlines the downstream process. Herein we have developed a cascade system for cladribine synthesis based on the sequential action of two magnetic biocatalysts. For that purpose, purine 2'-deoxyribosyltransferase from Leishmania mexicana (LmPDT) and Escherichia coli hypoxanthine phosphoribosyltransferase (EcHPRT) were immobilized onto Ni2+-prechelated magnetic microspheres (MagReSyn®NTA). Among the resulting derivatives, MLmPDT3 (activity: 11,935 IU/gsupport, 63% retained activity, operational conditions: 40 °C and pH 5-7) and MEcHPRT3 (12,840 IU/gsupport, 45% retained activity, operational conditions: pH 5-8 and 40-60 °C) emerge as optimal catalysts for further synthetic application. Moreover, the MLmPDT3/MEcHPRT3 system was biochemically characterized and successfully applied to the one-pot synthesis of cladribine under various conditions. This methodology not only displayed a 1.67-fold improvement in cladribine synthesis (compared to MLmPDT3), but it also implied a practically complete transformation of the undesired by-product into a high-added-value product (90% conversion of Hyp into IMP). Finally, MLmPDT3/MEcHPRT3 was reused for 16 cycles, which displayed a 75% retained activity.


Assuntos
Cladribina , Enzimas Imobilizadas , Enzimas Imobilizadas/química , Pentosiltransferases , Magnetismo , Escherichia coli , Fenômenos Magnéticos
6.
Int J Mol Sci ; 23(19)2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36233108

RESUMO

One of the major drawbacks of the industrial implementation of enzymatic processes is the low operational stability of the enzymes under tough industrial conditions. In this respect, the use of thermostable enzymes in the industry is gaining ground during the last decades. Herein, we report a structure-guided approach for the development of novel and thermostable 2'-deoxyribosyltransferases (NDTs) based on the computational design of disulfide bonds on hot spot positions. To this end, a small library of NDT variants from Lactobacillus delbrueckii (LdNDT) with introduced cysteine pairs was created. Among them, LdNDTS104C (100% retained activity) was chosen as the most thermostable variant, displaying a six- and two-fold enhanced long-term stability when stored at 55 °C (t1/255 °C ≈ 24 h) and 60 °C (t1/260 °C ≈ 4 h), respectively. Moreover, the biochemical characterization revealed that LdNDTS104C showed >60% relative activity across a broad range of temperature (30-90 °C) and pH (5-7). Finally, to study the potential application of LdNDTS104C as an industrial catalyst, the enzymatic synthesis of nelarabine was successfully carried out under different substrate conditions (1:1 and 3:1) at different reaction times. Under these experimental conditions, the production of nelarabine was increased up to 2.8-fold (72% conversion) compared with wild-type LdNDT.


Assuntos
Enzimas Imobilizadas , Pentosiltransferases , Arabinonucleosídeos , Cisteína , Dissulfetos/química , Estabilidade Enzimática , Enzimas Imobilizadas/química , Pentosiltransferases/metabolismo , Especificidade por Substrato , Temperatura
7.
Sci Rep ; 12(1): 17175, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36229494

RESUMO

Cobamides (Cbas) are coenzymes used by cells across all domains of life, but de novo synthesis is only found in some bacteria and archaea. Five enzymes assemble the nucleotide loop in the alpha phase of the corrin ring. Condensation of the activated ring and nucleobase yields adenosyl-Cba 5'-phosphate, which upon dephosphorylation yields the biologically active coenzyme (AdoCba). Base activation is catalyzed by a phosphoribosyltransferase (PRTase). The structure of the Salmonella enterica PRTase enzyme (i.e., SeCobT) is well-characterized, but archaeal PRTases are not. To gain insights into the mechanism of base activation by the PRTase from Methanocaldococcus jannaschii (MjCobT), we solved crystal structures of the enzyme in complex with substrate and products. We determined several structures: (i) a 2.2 Å structure of MjCobT in the absence of ligand (apo), (ii) structures of MjCobT bound to nicotinate mononucleotide (NaMN) and α-ribazole 5'-phosphate (α-RP) or α-adenylyl-5'-phosphate (α-AMP) at 2.3 and 1.4 Å, respectively. In MjCobT the general base that triggers the reaction is an aspartate residue (Asp 52) rather than a glutamate residue (E317) as in SeCobT. Notably, the dimer interface in MjCobT is completely different from that observed in SeCobT. Finally, entry PDB 3L0Z does not reflect the correct structure of MjCobT.


Assuntos
Cianobactérias , Euryarchaeota , Monofosfato de Adenosina , Archaea/metabolismo , Ácido Aspártico , Cobamidas/metabolismo , Cristalografia por Raios X , Cianobactérias/metabolismo , Euryarchaeota/metabolismo , Glutamatos , Ligantes , Pentosiltransferases/genética , Pentosiltransferases/metabolismo , Fosfatos/metabolismo
8.
Plant J ; 112(1): 193-206, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35959609

RESUMO

Grass xylan, the major hemicellulose in both primary and secondary cell walls, is heavily decorated with α-1,3-linked arabinofuranosyl (Araf) residues that may be further substituted at O-2 with xylosyl (Xyl) or Araf residues. Although xylan 3-O-arabinosyltransferases (XATs) catalyzing 3-O-Araf addition onto xylan have been characterized, glycosyltransferases responsible for the transfer of 2-O-Xyl or 2-O-Araf onto 3-O-Araf residues of xylan to produce the Xyl-Araf and Araf-Araf disaccharide side chains remain to be identified. In this report, we showed that a rice GT61 member, named OsXAXT1 (xylan arabinosyl 2-O-xylosyltransferase 1) herein, was able to mediate the addition of Xyl-Araf disaccharide side chains onto xylan when heterologously co-expressed with OsXAT2 in the Arabidopsis gux1/2/3 (glucuronic acid substitution of xylan 1/2/3) triple mutant that lacks any glycosyl substitutions. Recombinant OsXAXT1 protein expressed in human embryonic kidney 293 cells exhibited a xylosyltransferase activity catalyzing the addition of Xyl from UDP-Xyl onto arabinosylated xylooligomers. Consistent with its function as a xylan arabinosyl 2-O-xylosyltransferase, CRISPR-Cas9-mediated mutations of the OsXAXT1 gene in transgenic rice plants resulted in a reduction in the level of Xyl-Araf disaccharide side chains in xylan. Furthermore, we revealed that XAXT1 close homologs from several other grass species, including switchgrass, maize, and Brachypodium, possessed the same functions as OsXAXT1, indicating functional conservation of XAXTs in grass species. Together, our findings establish that grass XAXTs are xylosyltransferases catalyzing Xyl transfer onto O-2 of Araf residues of xylan to form the Xyl-Araf disaccharide side chains, which furthers our understanding of genes involved in xylan biosynthesis.


Assuntos
Arabidopsis , Oryza , Arabidopsis/genética , Arabidopsis/metabolismo , Parede Celular/metabolismo , Dissacarídeos/análise , Dissacarídeos/metabolismo , Ácido Glucurônico/análise , Ácido Glucurônico/química , Ácido Glucurônico/metabolismo , Glicosiltransferases/metabolismo , Humanos , Oryza/genética , Oryza/metabolismo , Pentosiltransferases , Plantas Geneticamente Modificadas/metabolismo , Difosfato de Uridina/metabolismo , Xilanos/metabolismo
9.
Microbiol Spectr ; 10(4): e0276321, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-35946941

RESUMO

Mycobacterium abscessus is an emerging human pathogen leading to significant morbidity and even mortality, intrinsically resistant to almost all the antibiotics available and so can be a nightmare. Mechanisms of its intrinsic resistance remain not fully understood. Here, we selected and confirmed an M. abscessus transposon mutant that is hypersensitive to multiple drugs including rifampin, rifabutin, vancomycin, clofazimine, linezolid, imipenem, levofloxacin, cefoxitin, and clarithromycin. The gene MAB_0189c encoding a putative arabinosyltransferase C was found to be disrupted, using a newly developed highly-efficient strategy combining next-generation sequencing and multiple PCR. Furthermore, selectable marker-free deletion of MAB_0189c recapitulated the hypersensitive phenotype. Disruption of MAB_0189c resulted in an inability to synthesize lipoarabinomannan and markedly enhanced its cell envelope permeability. Complementing MAB_0189c or M. tuberculosis embC restored the resistance phenotype. Importantly, treatment of M. abscessus with ethambutol, a first-line antituberculosis drug targeting arabinosyltransferases of M. tuberculosis, largely sensitized M. abscessus to multiple antibiotics in vitro. We finally tested activities of six selected drugs using a murine model of sustained M. abscessus infection and found that linezolid, rifabutin, and imipenem were active against the MAB_0189c deletion strain. These results identified MAB_0189 as a crucial determinant of intrinsic resistance of M. abscessus, and optimizing inhibitors targeting MAB_0189 might be a strategy to disarm the intrinsic multiple antibiotic resistance of M. abscessus. IMPORTANCE Mycobacterium abscessus is intrinsically resistant to most antibiotics, and treatment of its infections is highly challenging. The mechanisms of its intrinsic resistance remain not fully understood. Here we found a transposon mutant hypersensitive to a variety of drugs and identified the transposon inserted into the MAB_0189c (orthologous embC coding arabinosyltransferase, EmbC) gene by using a newly developed rapid and efficient approach. We further verified that the MAB_0189c gene played a significant role in its intrinsic resistance by decreasing the cell envelope permeability through affecting the production of lipoarabinomannan in its cell envelope. Lastly, we found the arabinosyltransferases inhibitor, ethambutol, increased activities of nine selected drugs in vitro. Knockout of MAB_0189c made M. abscessus become susceptible to 3 drugs in mice. These findings indicated that potential powerful M. abscessus EmbC inhibitor might be used to reverse the intrinsic resistance of M. abscessus to multiple drugs.


Assuntos
Infecções por Mycobacterium não Tuberculosas , Mycobacterium abscessus , Tuberculose , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Etambutol/uso terapêutico , Humanos , Imipenem/farmacologia , Imipenem/uso terapêutico , Linezolida/uso terapêutico , Camundongos , Camundongos Knockout , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Infecções por Mycobacterium não Tuberculosas/microbiologia , Mycobacterium abscessus/genética , Pentosiltransferases , Permeabilidade , Rifabutina/farmacologia , Rifabutina/uso terapêutico
10.
Seizure ; 101: 39-47, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35863218

RESUMO

PURPOSE: To delineate the seizure type, phenotype and V-EEG patterns of dystroglycanopathy (DGP) and correlate them with the neuroradiological and genetic results. METHODS: Patients with seizures were screened from our dystroglycanopathy database from January 2010 to March 2021. Detailed clinical information, including seizure type, brain magnetic resonance imaging (MRI), EEG and genetic analysis, was collected. RESULTS: Thirteen patients (15.1%, 13/86) had seizures. Most patients had a severe phenotype. The mean age at first seizure onset was 2 years and 8 months. The most common seizure type was generalized tonic-clonic seizure (GTCS), with 92.3% (12/13) induced by fever. Three patients were diagnosed with epilepsy. Most patients did not take any medicine. A few patients had irregular use of antiseizure medications (ASMs). Of the 13 patients, seven patients were diagnosed with MEB, four patients with POMGNT1 mutations, two with ISPD mutations, and one with POMT1 mutation. Three patients were diagnosed with FCMD with FKTN mutations. Two patients were diagnosed with CMD-MR, one patient with ISPD mutation, and one with POMT1 mutation. One patient was diagnosed with LGMD with FKRP mutation. Nine patients underwent EEG examination, and eight patients had abnormal EEG results, including abnormal background activities in three patients, abnormal background activities combined with paroxysmal discharges in three patients, pure paroxysmal discharges in one patient and positive phase sharp waves in the occipital region in one patient. For radiology, brain MRI was available for 12 patients. The brain MRI of nine patients showed type II lissencephaly. Two patients showed cerebellar hypoplasia and brainstem hypoplasia. One patient had a normal brain MRI result. Patients with type II lissencephaly usually had abnormal background activities and paroxysmal discharges. CONCLUSION: The seizure phenotype of dystroglycanopathy (DGP) is characterized by GTCS, which was the most common seizure type, while focal seizures and epileptic spasms could also occur in DGP patients. Most seizures were induced by fever. Seizures were relatively more frequent in severe phenotypes of DGP, such as FCMD and MEB. Abnormal background activities were the most common EEG patterns, which were closely related to type II lissencephaly.


Assuntos
Epilepsia , Lisencefalia , Convulsões , Eletroencefalografia , Epilepsia/diagnóstico , Epilepsia/genética , Humanos , Pentosiltransferases , Convulsões/genética
11.
ACS Chem Biol ; 17(8): 2229-2247, 2022 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-35815944

RESUMO

In tRNAAsp, tRNAAsn, tRNATyr, and tRNAHis of most bacteria and eukaryotes, the anticodon wobble position may be occupied by the modified nucleoside queuosine, which affects the speed and the accuracy of translation. Since eukaryotes are not able to synthesize queuosine de novo, they have to salvage queuine (the queuosine base) as a micronutrient from food and/or the gut microbiome. The heterodimeric Zn2+ containing enzyme tRNA-guanine transglycosylase (TGT) catalyzes the insertion of queuine into the above-named tRNAs in exchange for the genetically encoded guanine. This enzyme has attracted medical interest since it was shown to be potentially useful for the treatment of multiple sclerosis. In addition, TGT inactivation via gene knockout leads to the suppressed cell proliferation and migration of certain breast cancer cells, which may render this enzyme a potential target for the design of compounds supporting breast cancer therapy. As a prerequisite to fully exploit the medical potential of eukaryotic TGT, we have determined and analyzed a number of crystal structures of the functional murine TGT with and without bound queuine. In addition, we have investigated the importance of two residues of its non-catalytic subunit on dimer stability and determined the Michaelis-Menten parameters of murine TGT with respect to tRNA and several natural and artificial nucleobase substrates. Ultimately, on the basis of available TGT crystal structures, we provide an entirely conclusive reaction mechanism for this enzyme, which in detail explains why the TGT-catalyzed insertion of some nucleobases into tRNA occurs reversibly while that of others is irreversible.


Assuntos
Pentosiltransferases/química , Animais , Células Eucarióticas/metabolismo , Feminino , Guanina/metabolismo , Humanos , Camundongos , Nucleosídeo Q , RNA de Transferência/química
12.
J Microbiol Biotechnol ; 32(8): 1041-1046, 2022 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-35791073

RESUMO

Nucleoside deoxyribosyltransferase (NDT) is an enzyme that replaces the purine or pyrimidine base of 2'-deoxyribonucleoside. This enzyme is generally used in the nucleotide salvage pathway in vivo and synthesizes many nucleoside analogs in vitro for various biotechnological purposes. Since NDT is known to exhibit relatively low reactivity toward nucleoside analogs such as 2'-fluoro-2'-deoxynucleoside, it is necessary to develop an enhanced NDT mutant enzyme suitable for nucleoside analogs. In this study, molecular evolution strategy via error-prone PCR was performed with ndt gene derived from Lactobacillus leichmannii as a template to obtain an engineered NDT with higher substrate specificity to 2FDU (2'-fluoro-2'-deoxyuridine). A mutant library of 214 ndt genes with different sequences was obtained and performed for the conversion of 2FDU to 2FDA (2'-fluoro-2'-deoxyadenosine). The E. coli containing a mutant NDT, named NDTL59Q, showed 1.7-fold (at 40°C) and 4.4-fold (at 50°C) higher 2FDU-to-2FDA conversions compared to the NDTWT, respectively. Subsequently, both NDTWT and NDTL59Q enzymes were over-expressed and purified using a His-tag system in E. coli. Characterization and enzyme kinetics revealed that the NDTL59Q mutant enzyme containing a single point mutation of leucine to glutamine at the 59th position exhibited superior thermal stability with enhanced substrate specificity to 2FDU.


Assuntos
Escherichia coli , Nucleosídeos , Pentosiltransferases , Cinética , Pentosiltransferases/química , Especificidade por Substrato
13.
ACS Chem Biol ; 17(6): 1513-1523, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35670527

RESUMO

Ribitol phosphate modifications to the core M3 O-mannosyl glycan are important for the functional maturation of α-dystroglycan. Three sequentially extended partial structures of the core M3 O-mannosyl glycan including a tandem ribitol phosphate were regio- and stereo-selectively synthesized: Rbo5P-3GalNAcß, Rbo5P-1Rbo5P-3GalNAcß, and Xylß1-4Rbo5P-1Rbo5P-3GalNAcß (Rbo5P, d-ribitol-5-phosphate; GalNAc, N-acetyl-d-galactosamine; Xyl, d-xylose). Rbo5P-3GalNAcß with p-nitrophenyl at the aglycon part served as a substrate for ribitol phosphate transferase (FKRP, fukutin-related protein), and its product was glycosylated by the actions of a series of glycosyltransferases, namely, ribitol xylosyltransferase 1 (RXYLT1), ß1,4-glucuronyltransferase 1 (B4GAT1), and like-acetyl-glucosaminyltransferase (LARGE). Rbo5P-3GalNAcß equipped with an alkyne-type aglycon was also active for FKRP. The molecular information obtained on FKRP suggests that Rbo5P-3GalNAcß derivatives are the minimal units required as the acceptor glycan for Rbo5P transfer and may serve as a precursor for the elongation of the core M3 O-mannosyl glycan.


Assuntos
Fosfatos , Ribitol , Distroglicanas/química , Distroglicanas/metabolismo , Glicosilação , Pentosiltransferases/metabolismo , Polissacarídeos/metabolismo , Ribitol/metabolismo
14.
ACS Chem Biol ; 17(7): 1745-1755, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35763700

RESUMO

Understanding the structural arrangements of protein oligomers can support the design of ligands that interfere with their function in order to develop new therapeutic concepts for disease treatment. Recent crystallographic studies have elucidated a novel twisted and functionally inactive form of the homodimeric enzyme tRNA-guanine transglycosylase (TGT), a putative target in the fight against shigellosis. Active-site ligands have been identified that stimulate the rearrangement of one monomeric subunit by 130° against the other one to form an inactive twisted homodimer state. To assess whether the crystallographic observations also reflect the conformation in solution and rule out effects from crystal packing, we performed 19F-NMR spectroscopy with the introduction of 5-fluorotryptophans at four sites in TGT. The inhibitor-induced conformation of TGT in solution was assessed based on 19F-NMR chemical shift perturbations. We investigated the effect of C(4) substituted lin-benzoguanine ligands and identified a correlation between dynamic protein rearrangements and ligand-binding features in the corresponding crystal structures. These involve the destabilization of a helix next to the active site and the integrity of a flexible loop-helix motif. Ligands that either completely lack an attached C(4) substituent or use it to stabilize the geometry of the functionally competent dimer state do not indicate the presence of the twisted dimer form in the NMR spectra. The perturbation of crucial structural motifs in the inhibitors correlates with an increasing formation of the inactive twisted dimer state, suggesting these ligands are able to shift a conformational equilibrium from active C2-symmetric to inactive twisted dimer conformations. These findings suggest a novel concept for the design of drug candidates for further development.


Assuntos
Zymomonas , Domínio Catalítico , Cristalografia por Raios X , Guanina/metabolismo , Ligantes , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Pentosiltransferases/química , Conformação Proteica , RNA de Transferência/química , Zymomonas/química
15.
Int J Mol Sci ; 23(9)2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35563435

RESUMO

BACKGROUND: Xylosyltransferases-I and II (XT-I and XT-II) catalyze the initial and rate limiting step of the proteoglycan (PG) biosynthesis and therefore have an import impact on the homeostasis of the extracellular matrix (ECM). The reason for the occurrence of two XT-isoforms in all higher organisms remains unknown and targeted genome-editing strategies could shed light on this issue. METHODS: XT-I deficient neonatal normal human dermal fibroblasts were generated by using the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated proteins (Cas) 9 system. We analyzed if a reduced XT-I activity leads to abnormalities regarding ECM-composition, myofibroblast differentiation, cellular senescence and skeletal and cartilage tissue homeostasis. RESULTS: We successfully introduced compound heterozygous deletions within exon 9 of the XYLT1 gene. Beside XYLT1, we detected altered gene-expression levels of further, inter alia ECM-related, genes. Our data further reveal a dramatically reduced XT-I protein activity. Abnormal myofibroblast-differentiation was demonstrated by elevated alpha-smooth muscle actin expression on both, mRNA- and protein level. In addition, wound-healing capability was slightly delayed. Furthermore, we observed an increased cellular-senescence of knockout cells and an altered expression of target genes knowing to be involved in skeletonization. CONCLUSION: Our data show the tremendous relevance of the XT-I isoform concerning myofibroblast-differentiation and ECM-homeostasis as well as the pathophysiology of skeletal disorders.


Assuntos
Sistemas CRISPR-Cas , Pentosiltransferases , Pele , Sistemas CRISPR-Cas/genética , Fibroblastos/citologia , Fibroblastos/metabolismo , Edição de Genes , Humanos , Recém-Nascido , Pentosiltransferases/genética , Pentosiltransferases/metabolismo , Pele/metabolismo
16.
Cell Death Dis ; 13(4): 395, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35459861

RESUMO

Genomic instability plays a key role in the initiation and progression of colorectal cancer (CRC). Although cancer driver genes in CRC have been well characterized, identifying novel genes associated with carcinogenesis and treatment remains challenging because of tumor heterogeneity. Here, we analyzed the genomic alterations of 45 samples from CRC patients in northern China by whole-exome sequencing. In addition to the identification of six well-known CRC driver genes (APC, TP53, KRAS, FBXW7, PIK3CA, and PABPC), two tumor-related genes (MTCH2 and HSPA6) were detected, along with RRP7A and GXYLT1, which have not been previously linked to cancer. GXYLT1 was mutated in 40% (18/45) of the samples in our cohort. Functionally, GXYLT1 promoted migration and invasion in vitro and metastasis in vivo, while the GXYLT1S212* mutant induced significantly greater effect. Furthermore, both GXYLT1 and GXYLT1S212* interacted with ERK2. GXYLT1 induced metastasis via a mechanism involving the Notch and MAPK pathways, whereas the GXYLT1S212* mutant mainly promoted metastasis by activating the MAPK pathway. We propose that GXYLT1 acts as a novel metastasis-associated driver gene and GXYLT1S212* might serve as a potential indicator for therapies targeting the MAPK pathway in CRC.


Assuntos
Neoplasias Colorretais , Sistema de Sinalização das MAP Quinases , Pentosiltransferases , Carcinogênese/genética , China , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Humanos , Mutação/genética , Oncogenes , Pentosiltransferases/genética
17.
Int J Mol Sci ; 23(5)2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35269602

RESUMO

We determined the specificity of mutations induced by the CRISPR-Cas9 gene-editing system in tobacco (Nicotiana benthamiana) alleles and subsequent genetic stability. For this, we prepared 248 mutant plants using an Agrobacterium-delivered CRISPR-Cas9 system targeting α-1,3-fucosyltransferase 1 (FucT1) and ß-1,2-xylosyltransferase1 (XylT1) genes, for which the mutation rates were 22.5% and 25%, respectively, with 20.5% for both loci. Individuals with wild-type (WT) alleles at the NbFucT1 locus in T0 were further segregated into chimeric progeny (37-54%) in the next generation, whereas homozygous T0 mutants tended to produce more (~70%) homozygotes than other bi-allelic and chimeric progenies in the T1 generation. Approximately 81.8% and 77.4% of the homozygous and bi-allelic mutations in T0 generation, respectively, were stably inherited in the next generation, and approximately 50% of the Cas9-free mutants were segregated in T2 generation. One homozygous mutant (Ta 161-1) with a +1 bp insertion in NbFucT1 and a -4 bp deletion in NbXylT1 was found to produce T2 progenies with the same alleles, indicating no activity of the integrated Cas9 irrespective of the insertion or deletion type. Our results provide empirical evidence regarding the genetic inheritance of alleles at CRISPR-targeted loci in tobacco transformants and indicate the potential factors contributing to further mutagenesis.


Assuntos
Sistemas CRISPR-Cas , Tabaco , Alelos , Sistemas CRISPR-Cas/genética , Fucosiltransferases , Edição de Genes/métodos , Genes de Plantas , Humanos , Mutação , Pentosiltransferases , Plantas Geneticamente Modificadas/genética , Tabaco/genética
18.
Int J Mol Sci ; 23(5)2022 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-35269937

RESUMO

A comparative analysis of the transglycosylation conditions catalyzed by E. coli nucleoside phosphorylases, leading to the formation of 2'-deoxynucleosides, was performed. We demonstrated that maximal yields of 2'-deoxynucleosides, especially modified, can be achieved under small excess of glycosyl-donor (7-methyl-2'-deoxyguanosine, thymidine) and a 4-fold lack of phosphate. A phosphate concentration less than equimolar one allows using only a slight excess of the carbohydrate residue donor nucleoside to increase the reaction's output. A three-step methodology was elaborated for the preparative synthesis of purine-modified 2'-deoxyribonucleosides, starting from the corresponding ribonucleosides.


Assuntos
Ribonucleosídeos , Escherichia coli , Nucleosídeos/química , Pentosiltransferases , Fosfatos , Purina-Núcleosídeo Fosforilase , Purinas , Timidina
19.
Eur J Neurol ; 29(6): 1815-1824, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35239206

RESUMO

BACKGROUND AND PURPOSE: Hereditary myopathies with limb-girdle muscular weakness (LGW) are a genetically heterogeneous group of disorders, in which molecular diagnosis remains challenging. Our aim was to present a detailed clinical and genetic characterization of a large cohort of patients with LGW. METHODS: This nationwide cohort study included patients with LGW suspected to be associated with hereditary myopathies. Parameters associated with specific genetic aetiologies were evaluated, and we further assessed how they predicted the detection of causative variants by conducting genetic analyses. RESULTS: Molecular diagnoses were identified in 62.0% (75/121) of the cohort, with a higher proportion of patients diagnosed by next-generation sequencing (NGS) than by single-gene testing (77.3% vs. 22.7% of solved cases). The median (interquartile range) time from onset to genetic diagnosis was 8.9 (3.7-19.9) and 17.8 (7.9-27.8) years for single-gene testing and NGS, respectively. The most common diagnoses were myopathies associated with variants in CAPN3 (n = 9), FKRP (n = 9), ANO5 (n = 8), DYSF (n = 8) and SGCA (n = 5), which together accounted for 32.2% of the cohort. Younger age at disease onset (p = 0.043), >10× elevated creatine kinase activity levels (p = 0.024) and myopathic electromyography findings (p = 0.007) were significantly associated with the detection of causative variants. CONCLUSIONS: Our findings suggest that an earlier use of NGS in patients with LGW is needed to avoid long diagnostic delays. We further present parameters predictive of a molecular diagnosis that may help to select patients for genetic analyses, especially in centres with limited access to sequencing.


Assuntos
Doenças Musculares , Distrofia Muscular do Cíngulo dos Membros , Anoctaminas/genética , Áustria/epidemiologia , Estudos de Coortes , Humanos , Debilidade Muscular/genética , Distrofia Muscular do Cíngulo dos Membros/diagnóstico , Distrofia Muscular do Cíngulo dos Membros/genética , Mutação , Pentosiltransferases/genética
20.
Bioessays ; 44(5): e2100270, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35229908

RESUMO

The recently uncovered role of Fukutin-related protein (FKRP) in fibronectin glycosylation has challenged our understanding of the basis of disease pathogenesis in the muscular dystrophies. FKRP is a Golgi-resident glycosyltransferase implicated in a broad spectrum of muscular dystrophy (MD) pathologies that are not fully attributable to the well-described α-Dystroglycan hypoglycosylation. By revealing a new role for FKRP in the glycosylation of fibronectin, a modification critical for the development of the muscle basement membrane (MBM) and its associated muscle linkages, new possibilities for understanding clinical phenotype arise. This modification involves an interaction between FKRP and myosin-10, a protein involved in the Golgi organization and function. These observations suggest a FKRP nexus exists that controls two critical aspects to muscle fibre integrity, both fibre stability at the MBM and its elastic properties. This review explores the new potential disease axis in the context of our current knowledge of muscular dystrophies.


Assuntos
Fibronectinas , Distrofias Musculares , Distroglicanas/genética , Distroglicanas/metabolismo , Fibronectinas/genética , Fibronectinas/metabolismo , Glicosilação , Humanos , Músculo Esquelético , Distrofias Musculares/genética , Distrofias Musculares/metabolismo , Distrofias Musculares/patologia , Mutação , Pentosiltransferases/genética , Pentosiltransferases/metabolismo
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