Covalent modifications of histone tails have a key role in regulating chromatin structure and controlling transcriptional activity. In eukaryotes, histone H3 trimethylated at lysine 4 (H3K4me3) is ...associated with active chromatin and gene expression. We recently found that plant homeodomain (PHD) finger of tumour suppressor ING2 (inhibitor of growth 2) binds H3K4me3 and represents a new family of modules that target this epigenetic mark. The molecular mechanism of H3K4me3 recognition, however, remains unknown. Here we report a 2.0 Å resolution structure of the mouse ING2 PHD finger in complex with a histone H3 peptide trimethylated at lysine 4. The H3K4me3 tail is bound in an extended conformation in a deep and extensive binding site consisting of elements that are conserved among the ING family of proteins. The trimethylammonium group of Lys 4 is recognized by the aromatic side chains of Y215 and W238 residues, whereas the intermolecular hydrogen-bonding and complementary surface interactions, involving Ala 1, Arg 2, Thr 3 and Thr 6 of the peptide, account for the PHD finger's high specificity and affinity. Substitution of the binding site residues disrupts H3K4me3 interaction in vitro and impairs the ability of ING2 to induce apoptosis in vivo. Strong binding of other ING and YNG PHD fingers suggests that the recognition of H3K4me3 histone code is a general feature of the ING/YNG proteins. Elucidation of the mechanisms underlying this novel function of PHD fingers provides a basis for deciphering the role of the ING family of tumour suppressors in chromatin regulation and signalling.
The histone lysine demethylase KDM5B regulates gene transcription and cell differentiation and is implicated in carcinogenesis. It contains multiple conserved chromatin-associated domains, including ...three PHD fingers of unknown function. Here, we show that the first and third, but not the second, PHD fingers of KDM5B possess histone binding activities. The PHD1 finger is highly specific for unmodified histone H3 (H3K4me0), whereas the PHD3 finger shows preference for the trimethylated histone mark H3K4me3. RNA-seq analysis indicates that KDM5B functions as a transcriptional repressor for genes involved in inflammatory responses, cell proliferation, adhesion, and migration. Biochemical analysis reveals that KDM5B associates with components of the nucleosome remodeling and deacetylase (NuRD) complex and may cooperate with the histone deacetylase 1 (HDAC1) in gene repression. KDM5B is downregulated in triple-negative breast cancer relative to estrogen-receptor-positive breast cancer. Overexpression of KDM5B in the MDA-MB 231 breast cancer cells suppresses cell migration and invasion, and the PHD1-H3K4me0 interaction is essential for inhibiting migration. These findings highlight tumor-suppressive functions of KDM5B in triple-negative breast cancer cells and suggest a multivalent mechanism for KDM5B-mediated transcriptional regulation.
Display omitted
•KDM5B binds to its histone target and enzymatic product through distinct PHD fingers•KDM5B may cooperate with the NuRD complex in transcriptional repression•KDM5B suppresses migration and invasion of triple-negative breast cancer cells
The histone lysine demethylase KDM5B regulates gene transcription and cell differentiation. Here, Shi, Kutateladze, and colleagues find that the first and third PHD fingers of KDM5B have histone-binding activities. The authors show that KDM5B is downregulated in triple-negative breast cancer cells, functions as a transcriptional repressor for a set of genes, and suppresses cell migration and invasion ability. These findings highlight tumor-suppressive functions of KDM5B in triple-negative breast cancer cells and suggest a multivalent mechanism for KDM5B-mediated transcriptional repression.
► The Cytostat isolated sodium acetate resistant clones from overexpression library. ► ENA2 sodium pump overexpression improves growth under sodium acetate stress. ► Sodium strongly exacerbates the ...deleterious effect of acetic acid on Saccharomyces cerevisiae. ► Mechanism of resistance consists of coordinated transport of ions across membrane.
The production of biofuels from cellulosic biomass is a promising technology for developing a renewable source of energy. Efforts to produce ethanol from cellulosic biomass using microbes, such as the yeast Saccharomyces cerevisiae, face major challenges, including the need for detoxification. Here, we apply a strategy to discover genetic alterations that lead to improved robustness of S. cerevisiae in the presence of acetate, which is present at toxic concentrations in hemicellulose hydrolysates. Acetate in its protonated form (acetic acid) enters the cell through passive diffusion and dissociates into a proton and acetate, acidifying the cytosol and inhibiting cell function, an effect that is exacerbated in the presence of sodium. Through flow cytometry analysis, implemented as part of a novel cell culture technique, the Cytostat, we characterized the deleterious effects of sodium acetate on growth and on cell size homeostasis. Further, using the Cytostat to screen a genome-wide, gene overexpression library, we identified that overexpressing the ENA2 gene, a P-type sodium pump ATPase, provides a significant growth improvement in the presence of sodium acetate. Together, our data support the proposed mechanism for the synergistic growth inhibition exerted by acetate and sodium, as well as the mechanism that develops resistance.
This study was carried out with the objective of determining the antioxidant properties and quantification of total phenolics and flavonoids in relation to quercetin and rutin in some of the ...monofloral honeys produced in Minas Gerais (Brazil). In this study, 15 monofloral honey samples were obtained from different geographic regions of Minas Gerias, Brazil. The honeys were obtained from Cooperative of Beekeepers and Family Farmers of Northern Minas. To determine the antioxidant properties of honey samples, the test methods of total phenolic content, flavonoids (rutin and quercetin) and DPPH were used. As a result of the analysis of phenolic and flavonoid contents, the samples with the best results were A1-Aroeira and A4-Assa peixe. In antioxidant activity, the honey with the best EC50 results was A6-Aroeira. Differences between the antioxidant activities of the honey samples were found significantly (p< 0.01).
This work determined the sensitivity, specificity, and predictive values of a test evaluating the thermal perception threshold to cold and heat and established a thermal interval with the ...participant's basal temperature in order to detect diabetic peripheral neuropathy in 172 people with diabetes, 86 with and 86 without diabetic neuropathy.
This was a cross-sectional, diagnosis accuracy study.
This research was performed from January 2010 to February 2012 in Seville, Spain, and Córdoba, Spain.
One hundred seventy-two people with diabetes, 86 with and 86 without diabetic neuropathy, were recruited to participate in the study.
The thermal sensitivity was examined in the participants' feet with an instrument designed to assess thermal discrimination and sensitivity based on the Peltier principle. The skin temperature was recorded, and it was performed the following tests: (1) determining the thermal discrimination threshold, used to identify the lowest noticeable temperature difference, and (2) examining the thermal sensitivity, used to determine the absolute thermal threshold. The receiver operating characteristic curve technique was used to calculate the sensitivity, specificity, and predictive values.
The area under the curve that showed the best sensitivities and specificities bilaterally was for the warm temperatures under the first and fifth metatarsal heads. In these zones, the temperature difference needed to predict whether a patient was neuropathic was 2°C. Sensitivities were greater than 75%, and the positive predictive values in all cases exceeded 60%.
This technique enabled the authors to quantify the degrees of colder or warmer temperature differences that participants with diabetes (with and without neuropathy) needed to be able to detect a difference, with acceptable sensitivity, specificity, and predictive values.
Pes cavus is a structural deformity in which the increased plantar arch can lead to greater metatarsal verticality with the consequent excess of pressure under the forefoot zone (especially the ...metatarsal zone), causing pain and significant loss of functional capacity. We sought to determine whether neuromuscular stretching with symmetrical rectangular biphasic currents can reduce the pressure supported by this zone.
This prospective, nonrandomized, longitudinal, analytical, and experimental controlled trial included 34 patients with pes cavus. Pedobarometric measurements were made using the footscan USB Gait Clinical System platform considering the toes and metatarsal heads, forefoot, midfoot, and hindfoot before and after performing stretching using a Med Tens 931 electrotherapy device. The measurements were repeated 7 days after the application.
With the Student t test for paired samples, we showed that there was a significant decline in metatarsal pressure (P < .001) in the zones of the first (P = .045) and third (P = .01) metatarsals and that this reduction was maintained 1 week after the plantar stretching.
Plantar stretching with symmetrical rectangular biphasic currents is effective for the prevention and treatment of pes cavus metatarsalgia caused by excessive pressure.
Abstract
The goal of this study was to evaluate the performance and the carcass traits of Nelore cattle progenies from bulls selected by contrasting traits for precocity, growth and muscularity, ...through the Expected Progeny Difference (EPD). One hundred and five Nelore bulls (initial weight of 350kg±15kg) and 20 months of age were confined and fed with same diet (73% of concentrate). Thirty-two animals were selected to create the contrasting groups for precocity, growth and muscularity (16 animals assigned as a low EPD group - LEPD and 16 animals assigned as a high EPD group - HEPD), based on the EPD of their parents. The ribeye area and backfat thickness were performed by ultrasonography of 12–13th rib fat thickness and longissimus muscle area (LMA), as well as rump fat thickness (RF) measurements. Animals were harvested after 100 days and during the deboning, meat cuts were weight for cutting yield. The animals selected for the HEPD group had greater average daily gain (P = 0.006), which can be explained by the higher feed intake (P = 0.006). However, there are no difference between groups for the final body weight (P = 0.254) and feed efficiency (P = 0.715). The LEPD group presented higher dressing percentage (P = 0.028). Although the groups evaluated did not presented difference in LMA (P = 0.329) and weight of longissimus muscle (P = 0.480), the weight of rump displayed heaviest in the HEPD (P = 0.037). There was no difference between groups for RF (P = 0.086). Nevertheless, backfat thickness was higher in HEPD group (P = 0.006). The present study indicates that Nelore cattle progenies, with parents displaying higher potential for precocity, growth, and muscularity, show greater backfat thickness and weightiest of rump than the other genetic backgrounds. Thanks to FAPESP for the scholarship (Grant # 2017/02349–1).
This study was carried out with the objective of determining the antioxidant properties and quantification of total phenolics and flavonoids in relation to quercetin and rutin in some of the ...monofloral honeys produced in Minas Gerais (Brazil). In this study, 15 monofloral honey samples were obtained from different geographic regions of Minas Gerias, Brazil. The honeys were obtained from Cooperative of Beekeepers and Family Farmers of Northern Minas. To determine the antioxidant properties of honey samples, the test methods of total phenolic content, flavonoids (rutin and quercetin) and DPPH were used. As a result of the analysis of phenolic and flavonoid contents, the samples with the best results were A1-Aroeira and A4-Assa peixe. In antioxidant activity, the honey with the best EC50 results was A6-Aroeira. Differences between the antioxidant activities of the honey samples were found significantly (p< 0.01).
PDF
