Inhibition Of Elongation Research Articles

Translation initiation or elongation inhibition triggers contrasting effects on Caenorhabditis elegans survival during pathogen infection.

Several microbial pathogens target host protein synthesis machinery, potentially limiting the innate immune responses of the host. In response, hosts trigger a defensive response, elevating immune gene transcripts. This counterintuitive response can have either beneficial or harmful effects on host survival. In this study, we conduct a comprehensive analysis of the impact of knocking down various translation initiation and elongation factors on the survival of Caenorhabditis elegans exposed to Pseudomonas aeruginosa. Intriguingly, inhibiting initiation and elongation factors has contrasting effects on C. elegans survival. Inhibiting translation initiation activates immune responses that protect the host from bacterial infection, while inhibiting translation elongation induces aberrant immune responses that, although clear the infection, are detrimental to the host. Our study reveals divergent roles of translation initiation and elongation inhibition in C. elegans survival during P. aeruginosa infection and identifies differential transcriptional reprogramming that could underlie these differences.

Translation elongation inhibitors stabilize select short-lived transcripts.

Translation elongation inhibitors are commonly used to study different cellular processes. Yet, their specific impact on transcription and mRNA decay has not been thoroughly assessed. Here we use TimeLapse sequencing to investigate how translational stress impacts mRNA dynamics in human cells. Our results reveal that a distinct group of transcripts is stabilized in response to the translation elongation inhibitor emetine. These stabilized mRNAs are short-lived at steady state and many of them encode C2H2 zinc finger proteins. The codon usage of these stabilized transcripts is suboptimal compared to other expressed transcripts, including other short-lived mRNAs that are not stabilized after emetine treatment. Finally, we show that stabilization of these transcripts is independent of ribosome quality control factors and signaling pathways activated by ribosome collisions. Our data describe a group of short-lived transcripts whose degradation is particularly sensitive to the inhibition of translation elongation.

The RNA helicase DDX21 activates YAP to promote tumorigenesis and is transcriptionally upregulated by β-catenin in colorectal cancer

The RNA helicase DDX21 is vital for ribosome biogenesis and is upregulated in CRC, but the mechanism by which DDX21 is dysregulated and by which DDX21 promotes tumorigenesis in CRC remains poorly understood. Here, we showed that DDX21 is a direct transcriptional target gene of β-catenin and mediates the protumorigenic function of β-catenin in CRC. DDX21 expression is correlated with the expression and activity of β-catenin, and high DDX21 expression is associated with a poor prognosis in CRC patients. Loss of DDX21 leads to cytoplasmic translocation and decreased transcriptional activity of YAP and suppresses the proliferation and migration of CRC cells, which can be partially rescued by YAP reactivation. Importantly, by using translation elongation inhibitors and DNA intercalators, we showed that ribosomal stress upregulates DDX21 expression and induces the downregulation of LATS and the activation of YAP, probably through the ZAKα-MKK4/7-JNK axis. Overall, our study revealed the transcriptional activation mechanism of DDX21 in CRC and the activation of YAP in the ribosomal stress response, indicating the potential of combination therapy involving the induction of ribosomal stress and YAP inhibition.

Endothelial cell elongation and alignment in response to shear stress requires acetylation of microtubules.

The innermost layer of the vessel wall is constantly subjected to recurring and relenting mechanical forces by virtue of their direct contact with blood flow. Endothelial cells of the vessel are exposed to distension, pressure, and shear stress; adaptation to these hemodynamic forces requires significant remodeling of the cytoskeleton which includes changes in actin, intermediate filaments, and microtubules. While much is known about the effect of shear stress on the endothelial actin cytoskeleton; the impact of hemodynamic forces on the microtubule network has not been investigated in depth. Here we used imaging techniques and protein expression analysis to characterize how pharmacological and genetic perturbations of microtubule properties alter endothelial responses to laminar shear stress. Our findings revealed that pharmacological suppression of microtubule dynamics blocked two typical responses to laminar shear stress: endothelial elongation and alignment. The findings demonstrate the essential contribution of the microtubule network to changes in cell shape driven by mechanical forces. Furthermore, we observed a flow-dependent increase in microtubule acetylation that occurred early in the process of cell elongation. Pharmacological manipulation of microtubule acetylation showed a direct and causal relationship between acetylation and endothelial elongation. Finally, genetic inactivation of aTAT1, a microtubule acetylase, led to significant loss of acetylation as well as inhibition of cell elongation in response to flow. In contrast, loss of HDAC6, a microtubule deacetylase, resulted in robust microtubule acetylation with cells displaying faster kinetics of elongation and alignment. Taken together, our findings uncovered the critical contributions of HDAC6 and aTAT1, that through their roles in the regulation of microtubule acetylation, are key mediators of endothelial mechanotransduction.

Harnessing Trichoderma spp.: A Promising Approach to Control Apple Scab Disease.

Apple scab, caused by the pathogenic fungus Venturia inaequalis, can result in significant economic losses. The frequent use of fungicidal products has led to the emergence of isolates resistant to commonly used active substances. Therefore, biological control offers a sustainable alternative for managing apple scab. In this study, eight Trichoderma isolates were evaluated against five different isolates of V. inaequalis isolated from the Fes-Meknes region. The biocontrol potential of these Trichoderma isolates had previously been demonstrated against other pathogens. The results indicated that the inhibition rate of mycelial growth of V. inaequalis obtained with Trichoderma spp. isolates ranged from 50% to 81%, with significant differences observed among the pathogenic isolates after 5 and 12 days of incubation. In addition, the in vitro tests with Trichoderma cell-free filtrates showed inhibition rates ranging from 2% to 79%, while inhibition rates ranged from 5% to 78% for volatile compound tests. Interestingly, the inhibition of spore germination and elongation was approximately 40-50%, suggesting the involvement of antifungal metabolites in their biocontrol activities. The in vivo bioassay on detached apple leaves confirmed the biocontrol potential of these Trichoderma isolates and demonstrated their ability to preventively control apple scab disease. However, their efficacies were still lower than those of the fungicidal product difenoconazole. These findings could contribute to the development of an effective biofungicide based on these Trichoderma isolates for reliable and efficient apple scab control.

Preparation and anticancer activity of telomerase inhibitor TAT-LPTS39 polypeptide.

Telomerase is activated in most cancer cells, and thus telomerase is an ideal target for cancer therapy. The human liver-associated candidate tumour suppressor LPTS/PinX1, is the only human protein reported to bind with the telomerase catalytic subunit telomerase reverse transcriptase (TERT) and inhibit telomerase activity. The C-terminal fragment of LPTS/PinX1 (LPTS/PinX1290-328) contains a telomerase inhibitory domain that is needed for inhibition of telomere elongation and induction of apoptosis. This study prepared the TAT-LPTS39 (TAT-LPTS/PinX1290-328) polypeptide and analysed its effect of the tumour growth. LPTS/PinX1290-328 was fused with TAT [11 amino acid (aa) peptide of the HIV transactivator of transcription protein] to generate the recombinant protein GST-TAT-LPTS39 and was transduced into cells. Telomerase activity was identified by the telomeric repeat amplification protocol (TRAP) and the relative telomere length (RTL) was measured by quantitative real-time polymerase chain reaction (qPCR). The effects of the TAT-LPTS39 protein on cell growth and death were evaluated by 3-(4,5-dimethylthiazolyl)-2,5-diphenyltetrazolium bromide (MTT), cell culture doubling time and flow cytometry assays. The cell derived xenograft (CDX) model was used to examine tumour growth inhibition effect of TAT-LPTS39 polypeptide in vivo. We successfully expressed and purified the recombinant protein GST-TAT-LPTS39 in vitro. The GST-TAT-LPTS39 protein was efficiently delivered into cells, inhibited telomerase activity and the growth of the telomerase-positive liver cancer cells BEL-7404 and QGY7701, and induced the senescence and apoptosis in telomerase-positive Hela, BEL-7404 and QGY7701 cells, but was ineffective to telomerase-negative cells in vitro. The TAT-LPTS39 polypeptide without the GST tag similarly inhibited the growth of telomerase-positive cancer cells Hela and PLC-PRF-5 in vitro, BEL-7404 CDX tumour in vivo and shortened telomere length. The TAT-LPTS39 polypeptide has the ability to inhibit telomerase activity and suppress the growth of all tested human telomerase-positive cancer cells in vitro and in vivo, suggesting a potential anticancer drug development.

Soil arthropods in bioindication and ecotoxicological approach: The case of the extreme environment Mefite (Ansanto Valley, Southern Italy)

Soil arthropods are pivotal in maintaining soil health and serve as sensitive indicators of soil alterations. The soil arthropod community in the Mefite Geological Site (Italy), characterized by a sulphurous lake and intense degassing, was the focus of this study. In details, the objectives were: i) to characterize soil arthropod community at different distances from the Mefite lake; ii) to identify resilient taxa acting as bioindicators to assess soil ecotoxicity. Soil cores were collected at A) 30m, B) 80m, C) 120m away from the lake; soil organic matter (SOM), and pH, ecotoxicity tests (Lepidium sativum: germination index, elongation inhibition; Folsomia candida: survival, reproduction), and identification of soil arthropods (orders, Collembola families, Protura species) have been carried out. Statistical analyses assessed the impact of sulphurous emissions on soil chemistry, ecotoxicity, and arthropod parameters (community structure, taxa associations, biodiversity indices like Shannon and Simpson, and soil biological quality index – QBS-ar). The results showed: no SOM differences; pH: A < B < C; the highest ecotoxic effects were observed in A for both target species; arthropod community composition and QBS-ar varied notably in A compared to C, with the lowest soil biodiversity found in A. Hypogastruridae (Collembola) showed a clear association with A, while Protura were notably absent in A. This study also provided the first records of 4 Protura species in Campania, updating existing knowledge. Overall, arthropod community biodiversity and composition proved to be effective soil bioindicators in highly acidic conditions, reflecting soil ecotoxicity. In particular, the QBS-ar index demonstrated sensitivity in sulphurous environments.

BPA Exposure Affects Mouse Gastruloids Axial Elongation by Perturbing the Wnt/β-Catenin Pathway.

Mammalian embryos are very vulnerable to environmental toxicants (ETs) exposure. Bisphenol A (BPA), one of the most diffused ETs, exerts endocrine-disrupting effects through estro-gen-mimicking and hormone-like properties, with detrimental health effects, including on reproduction. However, its impact during the peri-implantation stages is still unclear. This study, using gastruloids as a 3D stem cell-based in vitro model of embryonic development, showed that BPA exposure arrests their axial elongation when present during the Wnt/β-catenin pathway activation period by β-catenin protein reduction. Gastruloid reshaping might have been impeded by the downregulation of Snail, Slug and Twist, known to suppress E-cadherin expression and to activate the N-cadherin gene, and by the low expression of the N-cadherin protein. Also, the lack of gastruloids elongation might be related to altered exit of BPA-exposed cells from the pluripotency condition and their following differentiation. In conclusion, here we show that the inhibition of gastruloids' axial elongation by BPA might be the result of the concomitant Wnt/β-catenin perturbation, reduced N-cadherin expression and Oct4, T/Bra and Cdx2 altered patter expression, which all together concur in the impaired development of mouse gastruloids.

Cytogenetic monitoring of spontaneous mutagenesis

Due to the challenging environmental situation in Ukraine, there is a need for cytogenetic monitoring, establishing cause-and-effect relationships, and assessing the toxic-mutagenic activity of environmental components. The results of such monitoring can serve as a basis for developing rehabilitation measures aimed at improving the environmental condition. Cytogenetic bioassay methods allow the evaluation of ecological and genetic risks to biota, considering the overall impact of pollutants, predicting changes in ecosystems, and making timely management decisions to improve environmental quality and preserve the nation’s gene pool. The article provides cytogenetic monitoring of apical meristems of the roots of Raphanus sativus subsp. radicula (Pers.) DC. and Allium cepa L. seedlings., grown on soils of residential areas, and the effect of ions of some elements on the cytological parameters of Pisum sativum L. was studied. It was noted that the spectrum of mitosis abnormalities and chromosome aberrations was expanded due to lagging chromosomes and micronuclei. Residential areas with a consistently high level of spontaneous cytogenetic disorders require the development of a local monitoring system to identify genetic hazards. The research on the proliferative activity of apical meristem cells confirms the hypothesis of aluminum toxicity to plants. Cytotoxic effects are assessed at the micro- and macroscopic levels. Macroscopically, reduced root growth of bioindicator plants was observed, which may result from several possible mechanisms: cell death, inhibition of division, cell elongation, or nutrient absorption. It was found that the duration of the prophase is directly influenced by the mobile forms of Zn and Pb, while Cu has a reverse effect. According to the results of multiple regression analysis, the most significant influence on these processes is exerted by the mobile forms of Zn, Cu, and Pb in the surface layers of the soils of the studied residential areas. Under the influence of AlCl3, the proportion of cells in the anaphase stage increases; CdCl2 affects the prophase stage; Na2SeO3 affects the meta- and anaphase stages; X-ray irradiation affects the telophase stage. Regarding the ability to induce the frequency of aberrant anaphases, a ranking can be constructed: Na2SeO3 (3.75·10–6 M) &gt; AlCl3 (3.86·10–5 M) &gt; CdCl2 (8.44·10–5 M). A radiation dose of 9.03·10–3 C/kg leads to the frequency of chromosomal aberrations, similar to the effects of AlCl3 (3.86·10–4 M) and Na2SeO3 (8.34·10–6 M). High concentrations of aluminum are associated with an increase in anaphases with fragments and two to three bridges.

NaHS immersion alleviates the stress effect of chromium(III) on alfalfa seeds by affecting active oxygen metabolism

ABSTRACT Objective This study aimed to investigate the regulatory effects of exogenous hydrogen sulfide (H2S) on seed germination, seedling growth, and reactive oxygen species (ROS) homeostasis in alfalfa under chromium (Cr) ion (III) stress. Methods The effects of 0–4 mM Cr(III) on the germination and seedling growth of alfalfa were first assessed. Subsequently, following seed NaHS immersion, the influence of H2S on alfalfa seed germination and seedling growth under 2 mM Cr(III) stress was investigated, and the substance contents and enzyme activities associated with ROS metabolism were quantified. Results Compared to the control group, alfalfa plant germination was delayed under 2 mM Cr(III) stress for up to 48 h (p < 0.05). At 120 h, the total seedling length was approximately halved, and the root length was roughly one-third of the control. Treatment with 0.02–0.1 mM NaHS alleviated the delay in germination and root growth inhibition caused by 2 mM Cr(III) stress, resulting in an increased ratio of root length to hypocotyl length from 0.57 to 1 above. Additionally, immersion in 0.05 mM NaHS reduced hydrogen peroxide (H2O2) and oxygen-free radicals (O2 · –) levels (p < 0.05), boosted glutathione (GSH) levels (p < 0.05), and notably enhanced catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities (p < 0.05) compared to the 2 mM Cr(III) stress treatment group. Conclusion Seed immersion in NaHS mitigated the delay in germination and inhibition of root elongation under 2 mM Cr(III) stress. This effect is likely attributed to the regulation of intracellular ROS homeostasis and redox balance through enzymatic and non-enzymatic systems; thus, providing a potential mechanism for combating oxidative stress.

Berberine analog of chloramphenicol exhibits a distinct mode of action and unveils ribosome plasticity

Chloramphenicol (CHL) is an antibiotic targeting the peptidyl transferase center in bacterial ribosomes. We synthesized a new analog, CAM-BER, by substituting the dichloroacetyl moiety of CHL with a positively charged aromatic berberine group. CAM-BER suppresses bacterial cell growth, inhibits protein synthesis invitro, and binds tightly to the 70S ribosome. Crystal structure analysis reveals that the bulky berberine group folds into the P site of the peptidyl transferase center (PTC), where it competes with the formyl-methionine residue of the initiator tRNA. Our toe-printing data confirm that CAM-BER acts as a translation initiation inhibitor in stark contrast to CHL, a translation elongation inhibitor. Moreover, CAM-BER induces a distinct rearrangement of conformationally restrained nucleotide A2059, suggesting that the 23S rRNA plasticity is significantly higher than previously thought. CAM-BER shows potential in avoiding CHL resistance and presents opportunities for developing novel berberine derivatives of CHL through medicinal chemistry exploration.

Endogenous cytokinins in plants of Secale cereale (Poaceae) under the effects of soil drought

Due to ongoing global climate changes and anthropogenic stress, soil drought has emerged as a significant threat, hindering plant growth, development, and resulting in crop losses. While phytohormones play a vital role in the formation of stress resistance mechanisms, cytokinins, in particular, remain poorly understood in cultivated cereals. The objective of our study was to investigate the impact of soil drought on plant growth and the homeostasis of endogenous cytokinins in both the aerial parts and roots of winter rye (Secale cereale) during the initial stages of vegetation. We aimed to elucidate the relationship between growth processes and the balance of these phytohormones. The plants were cultivated in a phytochamber using sand culture, and drought stress was induced by withholding water from nine-day-old plants for a period of eight days. The shoots and roots of 17-day-old plants were collected when dehydrated plants reached the critical wilting point. The content of endogenous cytokinins was analyzed using HPLC-MS. Our findings revealed that the inhibition of shoot growth and root elongation in stressed plants coincided with a reduction in the content of trans-zeatin riboside. This observation suggests that trans-zeatin riboside acts as a growth regulator in winter rye under soil drought conditions. Moreover, we observed an elevation in the levels of trans-zeatin and isopentenyladenine in the shoots and roots of stressed rye plants, indicating the involvement of these hormones in the formation of a "protective anti-stress block." These results highlight the multifunctional activity of cytokinins and demonstrate their role in regulating various components of the water deficit response. Consequently, our study expands our understanding of the role of cytokinins in the development of stress resistance in cereals.

The OsZIP2 transporter is involved in root-to-shoot translocation and intervascular transfer of cadmium in rice.

Cadmium (Cd) is a toxic metal that poses serious threats to human health. Rice is a major source of dietary Cd but how rice plants transport Cd to the grain is not fully understood. Here, we characterize the function of the ZIP (ZRT, IRT-like protein) family protein, OsZIP2, in the root-to-shoot translocation of Cd and intervascular transfer of Cd in nodes. OsZIP2 is localized at the plasma membrane and exhibited Cd2+ transport activity when heterologously expressed in yeast. OsZIP2 is strongly expressed in xylem parenchyma cells in roots and in enlarged vascular bundles in nodes. Knockout of OsZIP2 significantly enhanced root-to-shoot translocation of Cd and alleviated the inhibition of root elongation by excess Cd stress; whereas overexpression of OsZIP2 decreased Cd translocation to shoots and resulted in Cd sensitivity. Knockout of OsZIP2 increased Cd allocation to the flag leaf but decreased Cd allocation to the panicle and grain. We further reveal that the variation of OsZIP2 expression level contributes to grain Cd concentration among rice germplasms. Our results demonstrate that OsZIP2 functions in root-to-shoot translocation of Cd in roots and intervascular transfer of Cd in nodes, which can be used for breeding low Cd rice varieties.

Effects of orthokeratology on corneal reshaping and the delaying of axial eye growth in children

PurposeTo investigate the inhibition of myopia progression and axial elongation in children wearing orthokeratology (OK) lenses, as well as to evaluate the status of corneal reshaping, this study explores the relationship between changes in central corneal curvature (K-value) and e-value induced by OK lenses and axial elongation. MethodsIn this study, it is planned to select children aged 8–15 who wear orthokeratology lenses at the Pediatric Ophthalmology and Strabismus Clinic of the Second Affiliated Hospital of Dalian Medical University. All children will undergo slit lamp examination, visual acuity assessment, computerized refraction, intraocular pressure measurement, biometry, and corneal topography examination before lens wear and at 1 month, 3 months, and 6 months after lens wear in the pediatric ophthalmology clinic. Based on age (lower age group (8 < age ≤12 years); higher age group (12 < age ≤15 years)) and baseline equivalent spherical (SE) value (mild myopia group (−1.00 D < SE ≤ −3.25D); moderate myopia group (−3.25 D < SE ≤ −6.00 D)), four groups will be formed by pairing these factors. Suitable data will be selected according to inclusion and exclusion criteria, and different groups will be included. Data will be organized, and statistical analysis will be performed using SPSS software to obtain the results. The expected results will be discussed and analyzed. ResultsAfter wearing OK lenses, all four groups achieved good visual acuity at follow-up. At 6 months, there were no significant differences in visual acuity among the four groups (P = 0.149, >0.05). There were no significant differences in refractive error among the four groups (P = 0.066, >0.05). Baseline axial length differed significantly among the four groups (P = 0.000, <0.001), with the LM group having longer axial length than the LL group (P < 0.001, paired samples t-test), and the HM group having longer axial length than the HL group (P < 0.001, paired samples t-test). However, there were no significant differences in axial length change compared to baseline among the groups at 1 month, 3 months, and 6 months (P1 = 0.053; P3 = 0.557; P6 = 0.329, >0.05). Significant differences were observed in corneal flat K-value change compared to baseline among the four groups at 1 month, 3 months, and 6 months (P1 = 0.001, P3 = 0.001, P6 = 0.004, <0.05). There were no significant differences in e-value change among the groups at 1 and 3 months (P1 = 0.205, P3 = 0.252, >0.05), but significant differences were found in e-value change compared to baseline at 6 months (P6 = 0.010, <0.05). Multiple regression analysis with changes in central corneal flat K-value and e-value as independent variables and axial elongation as the dependent variable showed a correlation between e-value change at 6 months and axial elongation (P = 0.004, <0.05), indicating a negative correlation. ConclusionOrthokeratology (OK) lenses effectively improve myopic children's vision by reshaping the cornea, leading to reduced central corneal curvature and flattening of its anterior surface. The effectiveness of OK lenses is not significantly affected by age or initial myopia severity. Children of varying ages and myopia levels experience similar levels of axial length control with OK lens wear. Changes in corneal shape due to OK lenses affect axial elongation, with greater changes in corneal morphology associated with smaller increases in axial length.

The molecular basis of COP1 action during photomorphogenesis.

COP1 (CONSTITUTIVE PHOTOMORPHOGENIC1), a repressor of seedling photomorphogenesis, is tightly controlled by light. In Arabidopsis, COP1 primarily acts as a part of large E3 ligase complexes and targets key light-signaling factors for ubiquitination and degradation. Upon light perception, the action of COP1 is precisely modulated by active photoreceptors. During seedling development, light plays a predominant role in modulating seedling morphogenesis, including inhibition of hypocotyl elongation, cotyledon opening and expansion, and chloroplast development. These visible morphological changes evidently are resulted from networks of molecular action. In this review, we summarize the current knowledge about the molecular role of COP1 in mediating light-controlled seedling development.

Individual transcription factors modulate both the micromovement of chromatin and its long-range structure

The control of eukaryotic gene expression is intimately connected to highly dynamic chromatin structures. Gene regulation relies on activator and repressor transcription factors (TFs) that induce local chromatin opening and closing. However, it is unclear how nucleus-wide chromatin organization responds dynamically to the activity of specific TFs. Here, we examined how two TFs with opposite effects on local chromatin accessibility modulate chromatin dynamics nucleus-wide. We combine high-resolution diffusion mapping and dense flow reconstruction and correlation in living cells to obtain an imaging-based, nanometer-scale analysis of local diffusion processes and long-range coordinated movements of both chromatin and TFs. We show that the expression of either an individual transcriptional activator (CDX2) or repressor (SIX6) with large numbers of binding sites increases chromatin mobility nucleus-wide, yet they induce opposite coherent chromatin motions at the micron scale. Hi-C analysis of higher-order chromatin structures shows that induction of the pioneer factor CDX2 leads both to changes in local chromatin interactions and the distribution of A and B compartments, thus relating the micromovement of chromatin with changes in compartmental structures. Given that inhibition of transcription initiation and elongation by RNA Pol II has a partial impact on the global chromatin dynamics induced by CDX2, we suggest that CDX2 overexpression alters chromatin structure dynamics both dependently and independently of transcription. Our biophysical analysis shows that sequence-specific TFs can influence chromatin structure on multiple architectural levels, arguing that local chromatin changes brought by TFs alter long-range chromatin mobility and its organization.

Candidate genes conferring ethylene-response in cultivated peanuts determined by BSA-seq and fine-mapping

Ethylene plays essential roles in plant growth, development and stress responses. The ethylene signaling pathway and molecular mechanism have been studied extensively in Arabidopsis and rice but limited in peanuts. Here, we established a sand-culture method to screen pingyangmycin mutagenized peanut lines based on their specific response to ethylene (“triple response“). An ethylene-insensitive mutant, inhibition of peanut hypocotyl elongation 1 (iph1), was identified that showed reduced sensitivity to ethylene in both hypocotyl elongation and root growth. Through bulked segregant analysis sequencing, a major gene related to iph1, named AhIPH1, was preliminarily mapped at the chromosome Arahy.01, and further narrowed to a 450-kb genomic region through substitution mapping strategy. A total of 7014 genes were differentially expressed among the ACC treatment through RNA-seq analysis, of which only the Arahy.5BLU0Q gene in the candidate mapping interval was differentially expressed between WT and mutant iph1. Integrating sequence variations, functional annotation and transcriptome analysis revealed that a predicated gene, Arahy.5BLU0Q, encoding SNF1 protein kinase, may be the candidate gene for AhIPH1. This gene contained two single-nucleotide polymorphisms at promoter region and was more highly expressed in iph1 than WT. Our findings reveal a novel ethylene-responsive gene, which provides a theoretical foundation and new genetic resources for the mechanism of ethylene signaling in peanuts.

Identification of an anaplastic subtype of prostate cancer amenable to therapies targeting SP1 or translation elongation.

Histopathological heterogeneity is a hallmark of prostate cancer (PCa). Using spatial and parallel single-nucleus transcriptomics, we report an androgen receptor (AR)-positive but neuroendocrine-null primary PCa subtype with morphologic and molecular characteristics of small cell carcinoma. Such small cell-like PCa (SCLPC) is clinically aggressive with low AR, but high stemness and proliferation, activity. Molecular characterization prioritizes protein translation, represented by up-regulation of many ribosomal protein genes, and SP1, a transcriptional factor that drives SCLPC phenotype and overexpresses in castration-resistant PCa (CRPC), as two potential therapeutic targets in AR-indifferent CRPC. An SP1-specific inhibitor, plicamycin, effectively suppresses CRPC growth in vivo. Homoharringtonine, a Food And Drug Administration-approved translation elongation inhibitor, impedes CRPC progression in preclinical models and patients with CRPC. We construct an SCLPC-specific signature capable of stratifying patients for drug selectivity. Our studies reveal the existence of SCLPC in admixed PCa pathology, which may mediate tumor relapse, and establish SP1 and translation elongation as actionable therapeutic targets for CRPC.

Identification of hub genes involved in gibberellin-regulated elongation of coleoptiles of rice seeds germinating under submerged conditions.

Rapid elongation of coleoptiles from rice seeds to reach the water surface enables plants to survive submergence stress and therefore plays a crucial role in allowing direct seeding in rice cultivation. Gibberellin (GA) positively influences growth in rice, but the molecular mechanisms underlying its regulation of coleoptile elongation under submerged conditions remain unclear. In this study, we performed a weighted gene co-expression network analysis to conduct a preliminarily examination of the mechanisms. Four key modules were identified with high correlations to the GA regulation of submergence tolerance. The genes within these modules were mainly involved in the Golgi apparatus and carbohydrate metabolic pathways, suggesting their involvement in enhancing submergence tolerance. Further analysis of natural variation revealed that the specific hub genes Os03g0337900, Os03g0355600, and Os07g0638400 exhibited strong correlations with subspecies divergence of the coleoptile elongation phenotype. Consistent with this analysis, mutation of Os07g0638400 resulted in a lower germination potential and a stronger inhibition of coleoptile elongation under submerged conditions. The hub genes identified in this study provide new insights into the molecular mechanisms underlying GA-dependent tolerance to submergence stress in rice, and a potential basis for future modification of rice germplasm to allow for direct seeding.

Interaction of Gibberellic Acid and Glyphosate on Growth and Phenolic Metabolism in Soybean Seedlings

The plant growth regulator gibberellic acid (GA) and the herbicide glyphosate were examined for their possible interactions with growth and phenolic metabolism in soybean [Glycine max (L.) Merr. Cv. Hill] seedlings. GA caused increases in phenylalanine ammonia-lyase activity (PAL) (per axis basis) above those of the control seedling levels 48 h after treatment in light-grown seedlings. This effect increased to two-fold greater than control levels by 72 and 96 h after treatment. In dark-grown plants, GA had no effect on PAL levels at 24 h, reduced levels at 48 and 72 h, and increased PAL at 96 h. Early studies in our lab reported that glyphosate increased PAL levels, and also reduced hydroxyphenolic compound accumulation in both light- and dark-grown soybean seedlings. Treatments of GA plus glyphosate caused additive increases in PAL activity in light-grown seedlings, but GA lowered glyphosate’s increase in PAL levels at 48–96 h after treatment in dark-grown seedlings. GA had little effect on hydroxyphenolic compound levels in either light- or dark-grown seedlings. GA treatment alone did not significantly affect root elongation, but stimulated hypocotyl and epicotyl elongation and caused marginal reversal of glyphosate inhibition of elongation in roots, hypocotyls, and epicotyls in light-grown plants. These results show some differential effects of GA and glyphosate on growth and phenolic metabolism, and their interactions that are dependent on plants grown in light or darkness.