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1.
Cell ; 180(6): 1245-1261.e21, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32142654

RESUMO

In response to transcription-blocking DNA damage, cells orchestrate a multi-pronged reaction, involving transcription-coupled DNA repair, degradation of RNA polymerase II (RNAPII), and genome-wide transcription shutdown. Here, we provide insight into how these responses are connected by the finding that ubiquitylation of RNAPII itself, at a single lysine (RPB1 K1268), is the focal point for DNA-damage-response coordination. K1268 ubiquitylation affects DNA repair and signals RNAPII degradation, essential for surviving genotoxic insult. RNAPII degradation results in a shutdown of transcriptional initiation, in the absence of which cells display dramatic transcriptome alterations. Additionally, regulation of RNAPII stability is central to transcription recovery-persistent RNAPII depletion underlies the failure of this process in Cockayne syndrome B cells. These data expose regulation of global RNAPII levels as integral to the cellular DNA-damage response and open the intriguing possibility that RNAPII pool size generally affects cell-specific transcription programs in genome instability disorders and even normal cells.


Assuntos
Dano ao DNA , RNA Polimerase II/metabolismo , Reparo do DNA , Células HEK293 , Humanos , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Transcrição Gênica , Ubiquitinação , Raios Ultravioleta
2.
Cell ; 168(5): 843-855.e13, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28215706

RESUMO

The transcription-related DNA damage response was analyzed on a genome-wide scale with great spatial and temporal resolution. Upon UV irradiation, a slowdown of transcript elongation and restriction of gene activity to the promoter-proximal ∼25 kb is observed. This is associated with a shift from expression of long mRNAs to shorter isoforms, incorporating alternative last exons (ALEs) that are more proximal to the transcription start site. Notably, this includes a shift from a protein-coding ASCC3 mRNA to a shorter ALE isoform of which the RNA, rather than an encoded protein, is critical for the eventual recovery of transcription. The non-coding ASCC3 isoform counteracts the function of the protein-coding isoform, indicating crosstalk between them. Thus, the ASCC3 gene expresses both coding and non-coding transcript isoforms with opposite effects on transcription recovery after UV-induced DNA damage.


Assuntos
Processamento Alternativo/efeitos da radiação , DNA Helicases/genética , RNA não Traduzido/genética , Transcrição Gênica , Raios Ultravioleta , Linhagem Celular , Éxons , Humanos , RNA Polimerase II/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Elongação da Transcrição Genética/efeitos da radiação , Iniciação da Transcrição Genética/efeitos da radiação
3.
EMBO J ; 42(7): e112358, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36762421

RESUMO

The recognition of polyadenylation signals (PAS) in eukaryotic pre-mRNAs is usually coupled to transcription termination, occurring while pre-mRNA is chromatin-bound. However, for some pre-mRNAs, this 3'-end processing occurs post-transcriptionally, i.e., through a co-transcriptional cleavage (CoTC) event downstream of the PAS, leading to chromatin release and subsequent PAS cleavage in the nucleoplasm. While DNA-damaging agents trigger the shutdown of co-transcriptional chromatin-associated 3'-end processing, specific compensatory mechanisms exist to ensure efficient 3'-end processing for certain pre-mRNAs, including those that encode proteins involved in the DNA damage response, such as the tumor suppressor p53. We show that cleavage at the p53 polyadenylation site occurs in part post-transcriptionally following a co-transcriptional cleavage event. Cells with an engineered deletion of the p53 CoTC site exhibit impaired p53 3'-end processing, decreased mRNA and protein levels of p53 and its transcriptional target p21, and altered cell cycle progression upon UV-induced DNA damage. Using a transcriptome-wide analysis of PAS cleavage, we identify additional pre-mRNAs whose PAS cleavage is maintained in response to UV irradiation and occurring post-transcriptionally. These findings indicate that CoTC-type cleavage of pre-mRNAs, followed by PAS cleavage in the nucleoplasm, allows certain pre-mRNAs to escape 3'-end processing inhibition in response to UV-induced DNA damage.


Assuntos
Poliadenilação , Proteína Supressora de Tumor p53 , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Dano ao DNA , Precursores de RNA/genética , Precursores de RNA/metabolismo , Cromatina
4.
Proc Natl Acad Sci U S A ; 121(36): e2404042121, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39207735

RESUMO

The course of normal development and response to pathology are strongly influenced by biological sex. For instance, female childhood cancer survivors who have undergone cranial radiation therapy (CRT) tend to display more pronounced cognitive deficits than their male counterparts. Sex effects can be the result of sex chromosome complement (XX vs. XY) and/or gonadal hormone influence. The contributions of each can be separated using the four-core genotype mouse model (FCG), where sex chromosome complement and gonadal sex are decoupled. While studies of FCG mice have evaluated brain differences in adulthood, it is still unclear how sex chromosome and sex hormone effects emerge through development in both healthy and pathological contexts. Our study utilizes longitudinal MRI with the FCG model to investigate sex effects in healthy development and after CRT in wildtype and immune-modified Ccl2-knockout mice. Our findings in normally developing mice reveal a relatively prominent chromosome effect prepubertally, compared to sex hormone effects which largely emerge later. Spatially, sex chromosome and hormone influences were independent of one another. After CRT in Ccl2-knockout mice, both male chromosomes and male hormones similarly improved brain outcomes but did so more separately than in combination. Our findings highlight the crucial role of sex chromosomes in early development and identify roles for sex chromosomes and hormones after CRT-induced inflammation, highlighting the influences of biological sex in both normal brain development and pathology.


Assuntos
Encéfalo , Irradiação Craniana , Camundongos Knockout , Cromossomos Sexuais , Animais , Masculino , Feminino , Cromossomos Sexuais/genética , Encéfalo/metabolismo , Encéfalo/efeitos da radiação , Encéfalo/crescimento & desenvolvimento , Camundongos , Irradiação Craniana/efeitos adversos , Quimiocina CCL2/metabolismo , Quimiocina CCL2/genética , Hormônios Esteroides Gonadais/metabolismo , Imageamento por Ressonância Magnética
5.
Proc Natl Acad Sci U S A ; 121(5): e2314248121, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38266045

RESUMO

Interstitial atoms usually diffuse much faster than vacancies, which is often the root cause for the ineffective recombination of point defects in metals under irradiation. Here, via ab initio modeling of single-defect diffusion behavior in the equiatomic NiCoCrFe(Pd) alloy, we demonstrate an alloy design strategy that can reduce the diffusivity difference between the two types of point defects. The two diffusivities become almost equal after substituting the NiCoCrFe base alloy with Pd. The underlying mechanism is that Pd, with a much larger atomic size (hence larger compressibility) than the rest of the constituents, not only heightens the activation energy barrier (Ea) for interstitial motion by narrowing the diffusion channels but simultaneously also reduces Ea for vacancies due to less energy penalty required for bond length change between the initial and the saddle states. Our findings have a broad implication that the dynamics of point defects can be manipulated by taking advantage of the atomic size disparity, to facilitate point-defect annihilation that suppresses void formation and swelling, thereby improving radiation tolerance.

6.
Proc Natl Acad Sci U S A ; 120(15): e2218673120, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37014854

RESUMO

High- (and medium-) entropy alloys have emerged as potentially suitable structural materials for nuclear applications, particularly as they appear to show promising irradiation resistance. Recent studies have provided evidence of the presence of local chemical order (LCO) as a salient feature of these complex concentrated solid-solution alloys. However, the influence of such LCO on their irradiation response has remained uncertain thus far. In this work, we combine ion irradiation experiments with large-scale atomistic simulations to reveal that the presence of chemical short-range order, developed as an early stage of LCO, slows down the formation and evolution of point defects in the equiatomic medium-entropy alloy CrCoNi during irradiation. In particular, the irradiation-induced vacancies and interstitials exhibit a smaller difference in their mobility, arising from a stronger effect of LCO in localizing interstitial diffusion. This effect promotes their recombination as the LCO serves to tune the migration energy barriers of these point defects, thereby delaying the initiation of damage. These findings imply that local chemical ordering may provide a variable in the design space to enhance the resistance of multi-principal element alloys to irradiation damage.

7.
Proc Natl Acad Sci U S A ; 120(27): e2302785120, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-37364124

RESUMO

The increasing use of nuclear energy sources inevitably raises the risk of accidental or deliberate radiation exposure and associated immune dysfunction. However, the extent to which radiation exposure impacts memory CD8 T cells, potent mediators of immunity to recurring intracellular infections and malignancies, remains understudied. Using P14 CD8 T cell chimeric mice (P14 chimeras) with an lymphocytic choriomeningitis virus (LCMV) infection model, we observed that sublethal (5Gy) whole-body irradiation (WBI) induced a rapid decline in the number of naive (TN) and P14 circulating memory CD8 T cells (TCIRCM), with the former being more susceptible to radiation-induced numeric loss. While TN cell numbers rapidly recovered, as previously described, the number of P14 TCIRCM cells remained low at least 9 mo after radiation exposure. Additionally, the remaining P14 TCIRCM in irradiated hosts exhibited an inefficient transition to a central memory (CD62L+) phenotype compared to nonirradiated P14 chimeras. WBI also resulted in long-lasting T cell intrinsic deficits in memory CD8 T cells, including diminished cytokine and chemokine production along with impaired secondary expansion upon cognate Ag reencounter. Irradiated P14 chimeras displayed significantly higher bacterial burden after challenge with Listeria monocytogenes expressing the LCMV GP33-41 epitope relative to nonirradiated controls, likely due to radiation-induced numerical and functional impairments. Taken together, our findings suggest that sublethal radiation exposure caused a long-term numerical, impaired differentiation, and functional dysregulation in preexisting TCIRCM, rendering previously protected hosts susceptible to reinfection.


Assuntos
Coriomeningite Linfocítica , Irradiação Corporal Total , Camundongos , Animais , Recidiva Local de Neoplasia , Linfócitos T CD8-Positivos , Vírus da Coriomeningite Linfocítica , Memória Imunológica , Camundongos Endogâmicos C57BL
8.
J Biol Chem ; 300(1): 105509, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38042493

RESUMO

Today, the majority of patients with pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL, hereafter ALL) survive their disease, but many of the survivors suffer from life-limiting late effects of the treatment. ALL develops in the bone marrow, where the cells are exposed to cAMP-generating prostaglandin E2. We have previously identified the cAMP signaling pathway as a putative target for improved efficacy of ALL treatment, based on the ability of cAMP signaling to reduce apoptosis induced by DNA damaging agents. In the present study, we have identified the antioxidant N-acetyl cysteine (NAC) as a powerful modifier of critical events downstream of the cell-permeable cAMP analog 8-(4-chlorophenylthio) adenosine-3', 5'- cyclic monophosphate (8-CPT). Accordingly, we found NAC to turn 8-CPT into a potent killer of ALL cells in vitro both in the presence and absence of DNA damaging treatment. Furthermore, we revealed that NAC in combination with 8-CPT is able to delay the progression of ALL in a xenograft model in NOD-scid IL2Rγnull mice. NAC was shown to rely on the ability of 8-CPT to activate the guanine-nucleotide exchange factor EPAC, and we demonstrated that the ALL cells are killed by apoptosis involving sustained elevated levels of calcium imposed by the combination of the two drugs. Taken together, we propose that 8-CPT in the presence of NAC might be utilized as a novel strategy for treating pediatric ALL patients, and that this powerful combination might be exploited to enhance the therapeutic index of current ALL targeting therapies.


Assuntos
Acetilcisteína , AMP Cíclico , Fatores de Troca do Nucleotídeo Guanina , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Tionucleotídeos , Animais , Criança , Humanos , Camundongos , Acetilcisteína/farmacologia , Acetilcisteína/uso terapêutico , AMP Cíclico/análogos & derivados , AMP Cíclico/farmacologia , AMP Cíclico/uso terapêutico , DNA/efeitos dos fármacos , Fatores de Troca do Nucleotídeo Guanina/agonistas , Camundongos Endogâmicos NOD , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamento farmacológico , Masculino , Feminino , Pré-Escolar , Tionucleotídeos/farmacologia , Tionucleotídeos/uso terapêutico , Dano ao DNA , Quimioterapia Combinada
9.
Plant J ; 120(1): 272-288, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39190782

RESUMO

Among the three active aldehyde oxidases in Arabidopsis thaliana leaves (AAO1-3), AAO3, which catalyzes the oxidation of abscisic-aldehyde to abscisic-acid, was shown recently to function as a reactive aldehyde detoxifier. Notably, aao2KO mutants exhibited less senescence symptoms and lower aldehyde accumulation, such as acrolein, benzaldehyde, and 4-hydroxyl-2-nonenal (HNE) than in wild-type leaves exposed to UV-C or Rose-Bengal. The effect of AAO2 expression absence on aldehyde detoxification by AAO3 and/or AAO1 was studied by comparing the response of wild-type plants to the response of single-functioning aao1 mutant (aao1S), aao2KO mutants, and single-functioning aao3 mutants (aao3Ss). Notably, aao3Ss exhibited similar aldehyde accumulation and chlorophyll content to aao2KO treated with UV-C or Rose-Bengal. In contrast, wild-type and aao1S exhibited higher aldehyde accumulation that resulted in lower remaining chlorophyll than in aao2KO leaves, indicating that the absence of active AAO2 enhanced AAO3 detoxification activity in aao2KO mutants. In support of this notion, employing abscisic-aldehyde as a specific substrate marker for AAO3 activity revealed enhanced AAO3 activity in aao2KO and aao3Ss leaves compared to wild-type treated with UV-C or Rose-Bengal. The similar abscisic-acid level accumulated in leaves of unstressed or stressed genotypes indicates that aldehyde detoxification by AAO3 is the cause for better stress resistance in aao2KO mutants. Employing the sulfuration process (known to activate aldehyde oxidases) in wild-type, aao2KO, and molybdenum-cofactor sulfurase (aba3-1) mutant plants revealed that the active AAO2 in WT employs sulfuration processes essential for AAO3 activity level, resulting in the lower AAO3 activity in WT than AAO3 activity in aao2KO.


Assuntos
Aldeídos , Proteínas de Arabidopsis , Arabidopsis , Folhas de Planta , Raios Ultravioleta , Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Folhas de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/efeitos da radiação , Aldeídos/metabolismo , Aldeído Oxidase/metabolismo , Aldeído Oxidase/genética , Ácido Abscísico/metabolismo , Regulação da Expressão Gênica de Plantas , Mutação , Clorofila/metabolismo
10.
Trends Immunol ; 43(6): 459-465, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35490132

RESUMO

Much has been learned about the genes and pathways that contribute to a diverse array of hematopoietic malignancies and other hematopoietic diseases. However, for many of these diseases, an allogeneic hematopoietic stem cell (HSC) transplant remains the preferred treatment option. This opinion article provides the perspective of a molecular immunologist who became a transplant patient after many years studying basic mechanisms of blood cell development. Among many lessons learned were the magnitude of racial and ethnic disparities in donor registries, the substantial improvement in outcomes over time that were due to the collective impact of numerous advances, the benefits and limitations of genetic and clinical data, and the remarkably intricate balance between promoting graft-versus-disease activity of donor cells while suppressing graft-versus-host disease (GVHD).


Assuntos
Doença Enxerto-Hospedeiro , Neoplasias Hematológicas , Transplante de Células-Tronco Hematopoéticas , Doença Enxerto-Hospedeiro/genética , Humanos , Condicionamento Pré-Transplante , Transplante Homólogo
11.
Cell Mol Life Sci ; 81(1): 247, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38829550

RESUMO

BACKGROUND: The high degree of intratumoral genomic heterogeneity is a major obstacle for glioblastoma (GBM) tumors, one of the most lethal human malignancies, and is thought to influence conventional therapeutic outcomes negatively. The proneural-to-mesenchymal transition (PMT) of glioma stem cells (GSCs) confers resistance to radiation therapy in glioblastoma patients. POLD4 is associated with cancer progression, while the mechanisms underlying PMT and tumor radiation resistance have remained elusive. METHOD: Expression and prognosis of the POLD family were analyzed in TCGA, the Chinese Glioma Genome Atlas (CGGA) and GEO datasets. Tumorsphere formation and in vitro limiting dilution assay were performed to investigate the effect of UCHL3-POLD4 on GSC self-renewal. Apoptosis, TUNEL, cell cycle phase distribution, modification of the Single Cell Gel Electrophoresis (Comet), γ-H2AX immunofluorescence, and colony formation assays were conducted to evaluate the influence of UCHL3-POLD4 on GSC in ionizing radiation. Coimmunoprecipitation and GST pull-down assays were performed to identify POLD4 protein interactors. In vivo, intracranial xenograft mouse models were used to investigate the molecular effect of UCHL3, POLD4 or TCID on GCS. RESULT: We determined that POLD4 was considerably upregulated in MES-GSCs and was associated with a meagre prognosis. Ubiquitin carboxyl terminal hydrolase L3 (UCHL3), a DUB enzyme in the UCH protease family, is a bona fide deubiquitinase of POLD4 in GSCs. UCHL3 interacted with, depolyubiquitinated, and stabilized POLD4. Both in vitro and in vivo assays indicated that targeted depletion of the UCHL3-POLD4 axis reduced GSC self-renewal and tumorigenic capacity and resistance to IR treatment by impairing homologous recombination (HR) and nonhomologous end joining (NHEJ). Additionally, we proved that the UCHL3 inhibitor TCID induced POLD4 degradation and can significantly enhance the therapeutic effect of IR in a gsc-derived in situ xenograft model. CONCLUSION: These findings reveal a new signaling axis for GSC PMT regulation and highlight UCHL3-POLD4 as a potential therapeutic target in GBM. TCID, targeted for reducing the deubiquitinase activity of UCHL3, exhibited significant synergy against MES GSCs in combination with radiation.


Assuntos
Células-Tronco Neoplásicas , Tolerância a Radiação , Ubiquitina Tiolesterase , Humanos , Ubiquitina Tiolesterase/metabolismo , Ubiquitina Tiolesterase/genética , Tolerância a Radiação/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Células-Tronco Neoplásicas/efeitos da radiação , Animais , Camundongos , Linhagem Celular Tumoral , Glioma/patologia , Glioma/genética , Glioma/radioterapia , Glioma/metabolismo , Apoptose/genética , Apoptose/efeitos da radiação , Ubiquitinação , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/radioterapia , Camundongos Nus , Fenótipo , Regulação Neoplásica da Expressão Gênica , Prognóstico
12.
Nano Lett ; 24(1): 43-50, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-37930062

RESUMO

The defect emission from h-BN at 1.55 eV is interesting as it enables optical readout of spins. It is necessary to identify the nature of the relevant point defects for its controlled introduction. However, it is challenging to engineer point defects in h-BN without changing the local atomic structure. Here, we controllably introduce boron vacancies in h-BN using an ultrahigh spatial resolution and low-energy He+ ion beam. By optimizing the He+ ion irradiation conditions, we control the quantity and location of defects spatially and along the depth of h-BN to achieve a robust photoluminescence emission at 1.55 eV from 10 K to room temperature. We show that as-generated defects activate an additional Raman mode at 1295 cm-1. Electron energy loss spectroscopy confirms introduction of boron vacancies without modification of the local h-BN crystal structure. Our results provide a deterministic strategy to create scalable boron vacancy emitters in h-BN for quantum photonics.

13.
Nano Lett ; 24(18): 5662-5668, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38682870

RESUMO

The sensitivity of triboelectric nanogenerators (TENGs) to the surface charge density highlights the significance of triboelectric materials and their modifications. Efforts have been directed toward developing effective strategies for increasing the surface charge density, expanding the potential applications of TENGs. This study proposes the use of irradiation technology for grafting to modify the electron-donating capability of poly(ether sulfone) (PES), thereby affording a dual benefit of enhancing the surface charge density and inducing a shift in the position of PES from negative to positive within the triboelectric series. The TENG based on grafted PES has resulted in a significant 3-fold increase in surface charge density compared to that of pristine PES, reaching 263 µC m-2. The surface charge density can be further increased to 502 µC m-2 through charge pumping. Notably, irradiation technology presents advantages over chemical grafting methods, particularly in terms of sustainability and environmental friendliness. This innovative approach shows great potential in advancing the domain of TENGs.

14.
Nano Lett ; 24(36): 11302-11310, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39213538

RESUMO

Bradyarrhythmia poses a serious threat to human health, with chronic progression causing heart failure and acute onset leading to sudden death. In this study, we develop a scalable drug-mimicking nanoplasmonic therapeutic strategy by introducing gold nanorod (Au NR) mediated near-infrared (NIR) photothermal effects. An integrated sensing and regulation platform is established for in situ synchronized NIR laser regulation and electrophysiological property recording. The Au NR plasmonic regulation enables the restoration of normal cardiomyocyte rhythm from the bradyarrhythmia. By regulating the aspect ratio and concentration of Au NRs, as well as the intensity and time of NIR irradiation, we precisely optimized the plasmonic photothermal effect to explore effective therapeutic strategies. Furthermore, mRNA sequencing revealed a significant increase in the number of differentially expressed genes (DEGs) involved in the electrophysiological activities of cardiomyocytes following photothermal therapy. Au NR-mediated plasmonic photothermal therapy, as an efficient and noninvasive approach to bradyarrhythmia, holds profound implications for cardiology research.


Assuntos
Bradicardia , Ouro , Miócitos Cardíacos , Nanotubos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Ouro/química , Animais , Nanotubos/química , Bradicardia/terapia , Humanos , Terapia Fototérmica , Raios Infravermelhos , Camundongos
15.
Nano Lett ; 24(10): 3021-3027, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38252876

RESUMO

The effects on the lattice structure and electronic properties of different polymorphs of silver halide, AgX (X = Cl, Br, and I), induced by laser irradiation (LI) and electron irradiation (EI) are investigated using a first-principles approach, based on the electronic temperature (Te) within a two-temperature model (TTM) and by increasing the total number of electrons (Ne), respectively. Ab initio molecular dynamics (AIMD) simulations provide a clear visualization of how Te and Ne induce a structural and electronic transformation process during LI/EI. Our results reveal the diffusion processes of Ag and X ions, the amorphization of the AgX lattices, and a straightforward interpretation of the time evolution for the formation of Ag and X nanoclusters under high values of Te and Ne. Overall, the present work provides fine details of the underlying mechanism of LI/EI and promises to be a powerful toolbox for further cross-scale modeling of other semiconductors.

16.
Dev Biol ; 503: 83-94, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37619713

RESUMO

Within the chordates, only some colonial ascidians experience whole body regeneration (WBR), where amputated small colonial fragments containing blood-vessels have the capability to regenerate the entire functional adult zooid within 1-3 weeks. Studying WBR in small colonial fragments taken at different blastogenic stages (the weekly developmental process characteristic to botryllid ascidians) from the ascidian Botrylloides leachii, about half of the fragments were able to complete regeneration (cWBR) three weeks following separation, about half were still in uncomplete, running regeneration (rWBR), and only a small percentage died. cWBR significantly increased in fragments that originated from a late blastogenic stage compared to an early stage. Most B. leachii populations reside in shallow waters, under variable daily natural UV irradiation, and it is of interest to elucidate irradiation effects on development and regeneration. Here, we show that UV-B irradiation resulted in enhanced mortality, with abnormal morphological changes in surviving fragments, yet with non-significant cWBR vs. rWBRs. Further, UV-B irradiation influenced the proportion of blood cells (morula cells, hemoblasts) and of multinucleated cells, a new WBR-associated cell type. At 24-h post-amputation we observed enhanced expression of ß-catenin (a signaling pathway that plays indispensable roles in cell renewal and regeneration), H3 and PCNA in all cell types of non-irradiated as compared to irradiated fragments. These elevated levels were considerably reduced 9-days later. Since WBR is a highly complex phenomenon, the employment of specific experimental conditions, as UV-B irradiation, alongside blastogenesis (the weekly developmental process), elucidates undisclosed facets of this unique biological occurrence such as transient expression of signature genes.


Assuntos
Cordados , Gastrópodes , Urocordados , Animais , Amputação Cirúrgica , Corpo Celular
17.
Plant Mol Biol ; 114(5): 107, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39333431

RESUMO

Cucumber (Cucumis sativus L.) is a major vegetable crop grown globally, with a cultivation history of more than 3000 years. The limited genetic diversity, low rate of intraspecific variation, and extended periods of traditional breeding have resulted in slow progress in their genetic research and the development of new varieties. Gamma (γ)-ray irradiation potentially accelerates the breeding progress; however, the biological and molecular effects of γ-ray irradiation on cucumbers are unknown. Exposing cucumber seeds to 0, 50, 100, 150, 200, and 250 Gy doses of 60Co-γ-ray irradiation, this study aimed to investigate the resulting phenotype and physiological characteristics of seedling treatment to determine the optimal irradiation dose. The results showed that low irradiation doses (50-100 Gy) enhanced root growth, hypocotyl elongation, and lateral root numbers, promoting seedling growth. However, high irradiation doses (150-250 Gy) significantly inhibited seed germination and growth, decreasing the survival rate of seedlings. More than 100 Gy irradiation significantly decreased the total chlorophyll content while increasing the malondialdehyde (MDA) and H2O2 content in cucumber. Transcriptome sequencing analysis at 0, 50, 100, 150, 200, and 250 Gy doses showed that gene expression significantly differed between low and high irradiation doses. Gene Ontology enrichment and functional pathway enrichment analyses revealed that the auxin response pathway played a crucial role in seedling growth under low irradiation doses. Further, gene function analysis revealed that small auxin up-regulated gene CsSAUR37 was a key gene that was overexpressed in response to low irradiation doses, promoting primary root elongation and enhancing lateral root numbers by regulating the expression of protein phosphatase 2Cs (PP2Cs) and auxin synthesis genes.


Assuntos
Cucumis sativus , Raios gama , Regulação da Expressão Gênica de Plantas , Germinação , Proteínas de Plantas , Plântula , Plântula/efeitos da radiação , Plântula/crescimento & desenvolvimento , Plântula/genética , Cucumis sativus/efeitos da radiação , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Germinação/efeitos da radiação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos da radiação , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Radioisótopos de Cobalto , Relação Dose-Resposta à Radiação , Ácidos Indolacéticos/metabolismo , Clorofila/metabolismo , Sementes/efeitos da radiação , Sementes/crescimento & desenvolvimento , Sementes/genética , Perfilação da Expressão Gênica
18.
Emerg Infect Dis ; 30(6): 1291-1293, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38781985

RESUMO

Food irradiation can reduce foodborne illnesses but is rarely used in the United States. We determined whether outbreaks related to Campylobacter, Salmonella, Escherichia coli, and Listeria monocytogenes were linked to irradiation-eligible foods. Of 482 outbreaks, 155 (32.2%) were linked to an irradiation-eligible food, none of which were known to be irradiated.


Assuntos
Surtos de Doenças , Irradiação de Alimentos , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos , Humanos , Estados Unidos/epidemiologia , Doenças Transmitidas por Alimentos/epidemiologia , Doenças Transmitidas por Alimentos/microbiologia , História do Século XXI
19.
Curr Issues Mol Biol ; 46(9): 10606-10617, 2024 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-39329980

RESUMO

Citrus unshiu Marc. cv. Miyagawa-wase is one of the most widely cultivated citrus varieties on Jeju Island in Republic of Korea. Mutation breeding is a useful tool for inducing genetic diversity by causing genomic mutations in a short period of time. We previously conducted mutation breeding using gamma irradiation to develop new varieties of C. unshiu. Here, we describe one of these varieties, Yein-early, which has a redder peel, greater hardness, and higher sugar content compared with the wild type (WT). Yein-early leaves also showed a unique phenotype compared with the WT, characterized by longer longitudinal length, shorter transverse length, stronger curling, and longer petiole length. Genome resequencing of Yein-early and the WT uncovered significant single-nucleotide polymorphisms (SNPs) and insertions/deletions (InDels). These variations were crucial in identifying molecular markers unique to Yein-early. In addition, we developed an allele-specific PCR marker specifically targeting a homozygous SNP in Yein-early that distinguishes it from the WT and other citrus varieties. This study contributes to the understanding of pigment synthesis in fruits and provides a valuable tool for selection of the novel Yein-early variety in citrus breeding programs.

20.
Curr Issues Mol Biol ; 46(1): 450-460, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38248330

RESUMO

Developing strategies for the radiosensitization of cancer cells by the inhibition of genes, which harbor low toxicity to normal cells, will be useful for improving cancer radiotherapy. Here, we focused on a ß-site of amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1; ß-secretase, memapsin-2). By functional inhibition of this peptidase by siRNA, it has also recently been shown that the DNA strand break marker, γH2AX foci, increased, suggesting its involvement in DNA damage response. To investigate this possibility, we knocked down BACE1 with siRNA in cancer cell lines, and sensitization to γ-irradiation was examined by a colony formation assay, γH2AX foci and level analysis, and flow cytometry. BACE1 knockdown resulted in the sensitization of HeLa, MDA-MB-231, U2OS, and SAOS cells to γ-irradiation in a diverse range. BACE1 knockdown showed a weak radiosensitization effect in osteosarcoma U2OS cells, which has a normal p53 function. HeLa and SAOS cells, which harbor p53 dysfunction, exhibited a greater level of radiosensitization. These results suggest that BACE1 may be a potential target for the radiosensitization in particular cancer cells.

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