Inferential Comprehension Abilities in French-Speaking Preschoolers Exposed to Neglect in the Early Longitudinal Language and Neglect Study.

PURPOSE: Using a longitudinal design, this study aimed to describe inferential comprehension abilities of neglected French-speaking preschool children from 42 to 66 months of age in comparison to non-neglected peers, to examine the association with receptive vocabulary, and to determine whether rates of change in inferential abilities over time was stable between the two group conditions. METHOD: An inferential comprehension task and the French version of the Peabody Picture Vocabulary Test-Fourth Edition were administered to a group of neglected children (n = 37-40) and to a group of same-age non-neglected children (n = 71-91) at 42, 54, and 66 months old, as part of the Early Longitudinal Language and Neglect study. RESULTS: Results show that children exposed to neglect obtain significantly lower scores compared to their same-age peers on inferential comprehension and receptive vocabulary measures at all three time points (p < .001) with large to very large effect sizes and indicate moderate to strong correlations between the two variables. Children from the neglected group present difficulties in inferencing compared to same-age non-neglected peers, a disadvantage that remains stable over time. CONCLUSIONS: This study demonstrates the significant gap in inferential comprehension abilities between neglected and non-neglected preschool children. These results reiterate the importance of early detection of language comprehension difficulties in young children coming from vulnerable environments.

Developmental trajectories of speech and language in neglected children aged 3 to 5 years: Results of the ELLAN study.

BACKGROUND: Neglected children are at high risk for significant difficulties in speech and language development. Because no longitudinal study has been conducted to date, the dynamic description of development during the preschool period is unknown. OBJECTIVES: Establish the developmental trajectories of speech sounds, receptive and expressive vocabulary, and morphosyntax among neglected children during the preschool years and compare them with those of non-neglected children. PARTICIPANTS AND SETTING: Participants are 69 neglected children and 99 same age non-neglected peers (37 and 46 males respectively) recruited at 36 months of age. Data were collected at home. METHODS: Data were collected at six-month intervals between the ages of 3 and 5.5 years using psychometrically robust tools. Neglected and control groups were compared according to age using repeated measures ANOVAs on all variables. A discrete mixture model for clustering longitudinal data was used for testing the heterogeneity of the language trajectories among neglected children. RESULTS: The language development of the neglected children as a whole group is lower than that of the control group for all variables. Two subgroups are identified within the neglected group: one with a developmental trajectory similar to that of the non-neglected children, and another whose trajectory is far below that of the control group. The effect sizes of these differences vary between 1.4 and 3 standard deviations under the mean. CONCLUSIONS: A large proportion of neglected children present significant speech and language difficulties from the age of 3, but some of them catch up and develop similarly to non-neglected children.

Efficacy of prophylactic versus therapeutic administration of the NMDA receptor antagonist MK-801 on the acute neurochemical response to a concussion in a rat model combining force and rotation.

OBJECTIVE: Alterations in amino acid concentrations are a major contributor to the persistent neurological and behavioral effects induced by concussions and mild traumatic brain injuries (TBIs). Glutamate, the most abundant excitatory amino acid in the CNS, has a major role in the pathophysiological process of concussion. The indiscriminate liberation of glutamate immediately after a concussion triggers an excitotoxic response that leads to cell death, neuronal damage, and the dysfunction of surviving neurons, largely by overactivation of N-methyl-d-aspartate (NMDA) glutamatergic receptors. The aim of the present study was to investigate the efficacy of prophylactic versus therapeutic administration of MK-801, a promising NMDA receptor antagonist, on the acute changes in amino acid extracellular concentrations involved in excitotoxicity resulting from a concussive trauma. METHODS: The immediate neurochemical response to a concussion cannot be characterized in humans. Therefore, the authors used their previously validated combination of a weight-drop concussion rat model and in vivo cerebral microdialysis. The microdialysis probe was inserted inside the hippocampus and left inserted at impact to allow uninterrupted sampling of amino acids of interest immediately after concussion. The primary outcome included amino acid concentrations and the secondary outcome included righting time. Samples were taken in 10-minute increments for 60 minutes before, during, and 60 minutes after impact, and analyzed for glutamate, gamma-aminobutyric acid, taurine, glycine, glutamine, and serine using high-performance liquid chromatography. Righting time was acquired as a neurological restoration indicator. Physiological saline or 10 mg/kg MK-801 was administrated intraperitoneally 60 minutes before or immediately following induction of sham injury or concussion. RESULTS: Following induction of concussion, glutamate, taurine, and glycine levels as well as righting times in cases from the MK-801 treatment group were comparable to those of vehicle-treated animals. In contrast, righting times and amino acid concentrations observed within the first 10 minutes after induction of concussion in cases assigned to the MK-801 prophylaxis group were comparable to those of sham-injured animals. CONCLUSIONS: These results suggest that presynaptic actions and peak availability of MK-801 following prophylactic administration significantly inhibit the immediate and indiscriminate release of glutamate, taurine, and glycine in extracellular fluid after a concussion.

Profiles of teacher-child interaction quality in groups of 3-year-old children in Quebec and France.

Theory and studies support that educational quality may differ according to socio-political context even in states with similar cultures. Based on a secondary analysis of data, this study aims at identifying latent profiles of adult-child interaction quality in groups of three-year-old children in Quebec's (Canada) early childhood centers and France's kindergarten classrooms using the CLASS Pre-K. This study also aims to explore existing associations between identified profiles, socio-political contexts, and structural characteristics (staff qualifications, ages, group size). Latent profile analyses showed four interaction quality profiles, namely a high-quality profile (HQ), a medium-high-quality profile (MHQ), a medium quality profile (MQ), and a medium-low-quality profile (MLQ). The scores of the three CLASS Pre-K domains associated with identified profiles show a higher average interaction quality in Quebec compared with France, suggesting a more favorable sociocultural context for interaction quality in Quebec. As for characteristics of structural quality, analyses suggest that the group size variable is significantly associated with scores of interaction quality, with the HQ and the MHQ profiles showing a significantly lower group size than the MQ and MLQ profiles. Age is also significantly associated with profiles, exhibiting a general trend of younger participants found in higher quality profiles. Courses of action to enhance French policies are discussed.

PRMT1 promotes the tumor suppressor function of p14ARF and is indicative for pancreatic cancer prognosis.

The p14ARF protein is a well-known regulator of p53-dependent and p53-independent tumor-suppressive activities. In unstressed cells, p14ARF is predominantly sequestered in the nucleoli, bound to its nucleolar interaction partner NPM. Upon genotoxic stress, p14ARF undergoes an immediate redistribution to the nucleo- and cytoplasm, where it promotes activation of cell cycle arrest and apoptosis. Here, we identify p14ARF as a novel interaction partner and substrate of PRMT1 (protein arginine methyltransferase 1). PRMT1 methylates several arginine residues in the C-terminal nuclear/nucleolar localization sequence (NLS/NoLS) of p14ARF . In the absence of cellular stress, these arginines are crucial for nucleolar localization of p14ARF . Genotoxic stress causes augmented interaction between PRMT1 and p14ARF , accompanied by arginine methylation of p14ARF . PRMT1-dependent NLS/NoLS methylation promotes the release of p14ARF from NPM and nucleolar sequestration, subsequently leading to p53-independent apoptosis. This PRMT1-p14ARF cooperation is cancer-relevant and indicative for PDAC (pancreatic ductal adenocarcinoma) prognosis and chemotherapy response of pancreatic tumor cells. Our data reveal that PRMT1-mediated arginine methylation is an important trigger for p14ARF 's stress-induced tumor-suppressive function.

Systematic investigation of PRMT6 substrate recognition reveals broad specificity with a preference for an RG motif or basic and bulky residues.

Protein arginine methyltransferase 6 (PRMT6) catalyses the asymmetric dimethylation of arginines on numerous substrate proteins within the human cell. In particular, PRMT6 methylates histone H3 arginine 2 (H3R2) which affects both gene repression and activation. However, the substrate specificity of PRMT6 has not been comprehensively analysed. Here, we systematically characterise the substrate recognition motif of PRMT6, finding that it has broad specificity and recognises the RG motif. Working with a H3 tail peptide as a template, on which we made 204 amino acid substitutions, we use targeted mass spectrometry to measure their effect on PRMT6 in vitro activity. We first show that PRMT6 methylates R2 and R8 in the H3 peptide, although H3R8 is methylated with lower efficiency and is not an in vivo PRMT6 substrate. We then quantify the effect of 194 of these amino acid substitutions on methylation at both H3R2 and H3R8. In both cases, we find that PRMT6 tolerates essentially any amino acid substitution in the H3 peptide, but that positively charged and bulky residues are preferred near the target arginine. We show that PRMT6 also has preference for glycine, but only in the position immediately following the target arginine. This indicates that PRMT6 recognises the RG motif rather than the RGG motif. We further confirm this preference for the RG motif on another PRMT6 substrate, histone H4R3. This broad specificity and recognition of RG rather than RGG are distinctive among the PRMT family and has implications for the development of drugs to selectively target PRMT6. DATABASES: Panorama Public (https://panoramaweb.org/PRMT6motif.url); ProteomeXchange (PXD016711).

Targeting Uric Acid Prevents Brain Injury and Anxiety in a Rat Model of Hemorrhagic Shock.

ABSTRACT: Secondary brain injury following hemorrhagic shock (HS) is a frequent complication in patients, even in the absence of direct brain trauma, leading to behavioral changes and more specifically anxiety and depression. Despite preclinical studies showing inflammation and apoptosis in the brain after HS, none have addressed the impact of circulating mediators. Our group demonstrated an increased uric acid (UA) circulation in rats following HS. Since UA is implicated in endothelial dysfunction and inflammatory response, we hypothesized UA could alter the blood-brain barrier (BBB) and impact the brain. Male Wistar rats were randomly assigned to: SHAM, HS (hemorrhagic shock) and HS + U (hemorrhagic shock + 1.5 mg/kg of uricase). The uricase intervention, specifically targeting UA, was administered during fluid resuscitation. It prevented BBB dysfunction (fluorescein sodium salt permeability and expression of intercellular adhesion molecule-1) following HS. As for neuroinflammation, all of the results obtained (MPO activity; Iba1 and GFAP expression) showed a significant increase after HS, also prevented by the uricase. The same pattern was observed after quantification of apoptosis (caspase-3 activity and TUNEL) and neurodegeneration (Fluoro-Jade). Finally, the forced swim, elevated plus maze, and social interaction tests detected anxiety-like behavior after HS, which was blunted in rats treated with the uricase. In conclusion, we have identified UA as a new circulatory inflammatory mediator, responsible for brain alterations and anxious behavior after HS in a murine model. The ability to target UA holds the potential of an adjunctive therapeutic solution to reduce brain dysfunction related to hemorrhagic shock in human.

Impact of uric acid on liver injury and intestinal permeability following resuscitated hemorrhagic shock in rats.

BACKGROUND: Multiorgan failure is a consequence of severe ischemia-reperfusion injury after traumatic hemorrhagic shock (HS), a major cause of mortality in trauma patients. Circulating uric acid (UA), released from cell lysis, is known to activate proinflammatory and proapoptotic pathways and has been associated with poor clinical outcomes among critically ill patients. Our group has recently shown a mediator role for UA in kidney and lung injury, but its role in liver and enteric damage after HS remains undefined. Therefore, the objective of this study was to evaluate the role of UA on liver and enteric injury after resuscitated HS. METHODS: A murine model of resuscitated HS was treated during resuscitation with a recombinant uricase, a urate oxidase enzyme (rasburicase; Sanofi-Aventis, Canada Inc, Laval, Canada), to metabolize and reduce circulating UA. Biochemical analyses (liver enzymes, liver apoptotic, and inflammatory markers) were performed at 24 hours and 72 hours after HS. Physiological testing for enteric permeability and gut bacterial product translocation measurement (plasma endotoxin) were performed 72 hours after HS. In vitro, HT-29 cells were exposed to UA, and the expression of intercellular adhesion proteins (ZO-1, E-cadherin) was measured to evaluate the influence of UA on enteric permeability. RESULTS: The addition of uricase to resuscitation significantly reduced circulating and liver UA levels after HS. It also prevented HS-induced hepatolysis and liver apoptotic/inflammatory mediators at 24 hours and 72 hours. Hemorrhagic shock-induced enteric hyperpermeability and endotoxemia were prevented with uricase. CONCLUSIONS: After resuscitated HS, UA is an important mediator in liver and enteric injury. Uric acid represents a therapeutic target to minimize organ damage in polytrauma patients sustaining HS.

The importance of Calanus glacialis for the feeding success of young polar cod: a circumpolar synthesis.

Understanding the feeding ecology of polar cod (Boreogadus saida) during its first year of life is crucial to forecasting its response to the ongoing borealization of Arctic seas. We investigated the relationships between diet composition and feeding success in 1797 polar cod larvae and juveniles 4.5-55.6 mm standard length (SL) collected in five Arctic seas from 1993 to 2009. Prey were identified to species and developmental stages when possible, measured, and their carbon content was estimated using taxon-specific allometric equations. Feeding success was defined as the ratio of ingested carbon to fish weight. Carbon uptake in polar cod larvae < 15 mm was sourced primarily from calanoid copepods eggs and nauplii which were positively selected from the plankton. With increasing length, carbon sources shifted from eggs and nauplii to the copepodites of Calanus glacialis, Calanus hyperboreus and Pseudocalanus spp. Calanus glacialis copepodites were the main carbon source in polar cod > 25 mm and the only copepodite positively selected for. Pseudocalanus spp. copepodites became important replacement prey when C. glacialis left the epipelagic layer at the end of summer. Calanus glacialis was the preferred prey of polar cod, contributing from 23 to 84% of carbon uptake at any stage in the early development. Feeding success was determined by the number of prey captured in larvae < 15 mm and by the size of prey in juveniles > 30 mm. As Arctic seas warm, the progressive displacement of C. glacialis by the smaller Calanus finmarchicus could accelerate the replacement of polar cod, the dominant Arctic forage fish, by boreal species.

Parental behaviors associated with the level of pragmatic language ability among 42-month-old neglected children.

BACKGROUND: Exposure to neglect can severely compromise children's pragmatic skills (social language use). The disruptions of parent-child interactions that typically occur in context of neglect may compromise several parental behaviors which are known to foster language skills such as pragmatics. OBJECTIVES: 1- Compare the behaviors of neglectful and non-neglectful parents in four domains which are of interest for pragmatic language development, namely, responsive, supportive, affective, and control behaviors, and 2- Identify parental behaviors associated with the levels of pragmatic ability of 42-month-old neglected children. PARTICIPANTS: Study sample consisted of 21 neglected children living in their biological family, recruited in four Youth Centers in the province of Québec (Canada) and 95 non-neglected children recruited in child-care centers. METHOD: Parental behaviors were video recorded in context of free-play with the child at the participants' homes between 2015 and 2017, and subsequently analyzed using the Coding Observations of Parent-Child Interactions (COPI), developed to observe ten parental behaviors associated with early language development. The level of pragmatic ability of children was established using the Language Use Inventory: French, a standardized questionnaire completed with parents of both groups. RESULTS: Parents in situation of neglect scored lower than parents in the control group on eight of the ten behaviors (p < .001). Parental reciprocity was associated with the level of pragmatic ability of 42-month-old neglected children (p = .04). CONCLUSIONS: The results of this exploratory study provide insight on the associations between parental behaviors and the level of pragmatic language skills of children experiencing neglect.

Assaying epigenome functions of PRMTs and their substrates.

Among the widespread and increasing number of identified post-translational modifications (PTMs), arginine methylation is catalyzed by the protein arginine methyltransferases (PRMTs) and regulates fundamental processes in cells, such as gene regulation, RNA processing, translation, and signal transduction. As epigenetic regulators, PRMTs play key roles in pluripotency, differentiation, proliferation, survival, and apoptosis, which are essential biological programs leading to development, adult homeostasis but also pathological conditions including cancer. A full understanding of the molecular mechanisms that underlie PRMT-mediated gene regulation requires the genome wide mapping of each player, i.e., PRMTs, their substrates and epigenetic marks, methyl-marks readers as well as interaction partners, in a thorough and unambiguous manner. However, despite the tremendous advances in high throughput sequencing technologies and the numerous efforts from the scientific community, the epigenomic profiling of PRMTs as well as their histone and non-histone substrates still remains a big challenge owing to obvious limitations in tools and methodologies. This review will summarize the present knowledge about the genome wide mapping of PRMTs and their substrates as well as the technical approaches currently in use. The limitations and pitfalls of the technical tools along with conventional approaches will be then discussed in detail. Finally, potential new strategies for chromatin profiling of PRMTs and histone substrates will be proposed and described.

Morphosyntactic Development and Severe Parental Neglect in 4-Year-Old French-Speaking Children: ELLAN study.

Language is the most frequently compromised area of development in English-speaking neglected children, particularly the morphosyntactic component of language. This is very worrisome given its central role in academic success and social participation. No previous study has examined the morphosyntactic skills of French-speaking neglected children, despite the morphological richness of French. This study aimed to fill this gap. Forty-four neglected (mean age = 48.32 months, SD = 0.45) and 92 non-neglected (mean age = 48.07 months, SD = 0.24) French-speaking children participated. Measures of morphosyntactic skills were derived from a sample of spontaneous language collected during standardized semistructured play and analyzed using Systematic Analysis of Language Transcripts software (2012) . Four morphosyntactic indicators were compared using analyses of variance and Kolmogorov-Smirnov tests: the mean length of utterances (MLU), verbal inflections, word-level errors, and omission errors. The results indicate that 25.6% of the neglected children presented clinically significant morphosyntactic difficulties, as evidenced by a significantly shorter MLU (M = 5.60, SD = 1.13; M = 6.90, SD = 1.30), fewer verbal inflections, and more frequent word omission errors compared to their non-neglected peers. The results confirm that French-speaking neglected children present many morphosyntactic difficulties. This study argues for sustained speech-language services for these children.

The Pragmatic Language Skills of Severely Neglected 42-Month-Old Children: Results of the ELLAN Study.

The goals of this study were twofold: (1) to compare the pragmatic language skills (i.e., social communication skills) of 42-month-old neglected children with those of same-aged non-neglected children and (2) to measure the prevalence of pragmatic difficulties among the neglected children. The study sample was composed of 45 neglected and 95 non-neglected 42-month-old French-speaking children. The Language Use Inventory: French (LUI-French) was completed with all parents. This measure, comprised of 159 scored items divided into 10 subscales, was used to assess the children's pragmatic skills. The 10th percentile on the LUI-French (95% confidence interval ) was used to identify children with pragmatic difficulties. The neglected children had lower scores than the non-neglected children on all 10 dimensions of pragmatics evaluated (p < .01), as well as lower LUI-French Total Scores (p < .001). The effect sizes of these differences varied between 0.84 and 2.78. Forty-four percent of the neglected children presented significant pragmatic difficulties compared to 4.2% of their non-neglected peers (p < .001). It can be concluded that exposure to neglect significantly compromises children's pragmatic skills. These results support the need for interventions geared toward neglected children and their families to support the early development of their pragmatic skills.

Caspase-(8/3) activation and organ inflammation in a rat model of resuscitated hemorrhagic shock: A role for uric acid.

BACKGROUND: Multiple organ failure can develop after hemorrhagic shock (HS). Uric acid (UA) is released from dying cells and can be proinflammatory. We hypothesized that UA could be an alternative mediator of organ apoptosis and inflammation after HS. METHODS: Ventilated male Wistar rats were used for the HS model. Two durations of shock (5 minutes vs. 60 minutes) were compared, and shams were instrumented only; animals were resuscitated and observed for 24 hours/72 hours. Caspases-(8/3), myeloperoxidase (MPO), TNF-α were measured in lungs and kidneys. Plasma UA and cytokine (IL-1ß, IL-18, TNF-α) were measured. A second set of animals were randomized to vehicle versus Rasburicase intraperitoneal intervention (to degrade UA) during resuscitation. Another group received exogenous UA intraperitoneally without HS. Measures mentioned above, in addition to organs UA, were performed at 24 hours. In vitro, caspases-(8/3) activity was tested in epithelial cells exposed to UA. RESULTS: Hemorrhagic shock increased organ (kidney and lung) TNF-α, MPO, and caspases activity in various patterns while caspase-8 remained elevated over time. Hemorrhagic shock led to increased plasma UA at 2 hours, which remained high until 72 hours; TNF-α and IL-18 were elevated at 24 hours. The exogenous UA administration in sham animals reproduced the activation of caspase-8 and MPO in organs, and TNF-α in the lung. The increased plasma and organ UA levels, plasma and lung TNF-α, as well as organ caspase-(8/3) and MPO, observed at 24 hours after HS, were prevented by the administration of Rasburicase during resuscitation. In vitro, soluble UA induced caspases-(3/8) activity in epithelial cells. CONCLUSION: Uric acid is persistently high after HS and leads to the activation of caspases-8 and organ inflammation; these can be prevented by an intervention to degrade UA. Therefore, UA is an important biomarker and mediator that could be considered a therapeutic target during HS resuscitation in human.

Fluid sparing and norepinephrine use in a rat model of resuscitated haemorrhagic shock: end-organ impact.

BACKGROUND: Haemostasis and correction of hypovolemia are the pillars of early haemorrhage shock (HS) management. Vasopressors, which are not recommended as first-line therapy, are an alternative to aggressive fluid resuscitation, but data informing the risks and benefits of vasopressor therapy as fluid-sparing strategy is lacking. We aimed to study its impact on end organs, in the setting of a haemodynamic response to the initial volume resuscitation. METHODS: Following controlled HS (60 min) induced by blood withdrawal, under anaesthesia and ventilation, male Wistar rats (N = 10 per group) were randomly assigned to (1) sham, (2) HS with fluid resuscitation only [FR] and (3) HS with fluid resuscitation to restore haemodynamic (MAP: mean arterial pressure) then norepinephrine [FR+NE]. After a reperfusion time (60 min) during which MAP was maintained with fluid or norepinephrine, equipment was removed and animals were observed for 24 h (N = 5) or 72 h (N = 5) before euthanasia. Besides haemodynamic parameters, physiological markers (creatinine, lactate, pH, PaO2) and one potential contributor to vasoplegia (xanthine oxidase activity) were measured. Apoptosis induction (caspase 3), tissue neutrophil infiltration (MPO: myeloperoxidase) and illustrative protein markers were measured in the lung (Claudin-4), kidney (KIM-1) and brain amygdala (Iba1). RESULTS: No difference was present in MAP levels during HS or reperfusion between the two resuscitation strategies. FR required significantly more fluid than FR+NE (183% vs 106% of bleed-out volume; p = 0.003), when plasma lactate increased similarly. Xanthine oxidase was equally activated in both HS groups. After FR+NE, creatinine peaked higher but was similar in all groups at later time points. FR+NE enhanced MPO in the lung, when Claudin-4 increased significantly after FR. In the brain amygdala, FR provoked more caspase 3 activity, MPO and microglial activation (Iba1 expression). CONCLUSION: Organ resuscitation after controlled HS can be assured with lesser fluid administration followed by vasopressors administration, without signs of dysoxia or worse evolution. Limiting fluid administration could benefit the brain and seems not to have a negative impact on the lung or kidney.

Genomic Location of PRMT6-Dependent H3R2 Methylation Is Linked to the Transcriptional Outcome of Associated Genes.

Protein arginine methyltransferase 6 (PRMT6) catalyzes asymmetric dimethylation of histone H3 at arginine 2 (H3R2me2a). This mark has been reported to associate with silent genes. Here, we use a cell model of neural differentiation, which upon PRMT6 knockout exhibits proliferation and differentiation defects. Strikingly, we detect PRMT6-dependent H3R2me2a at active genes, both at promoter and enhancer sites. Loss of H3R2me2a from promoter sites leads to enhanced KMT2A binding and H3K4me3 deposition together with increased target gene transcription, supporting a repressive nature of H3R2me2a. At enhancers, H3R2me2a peaks co-localize with the active enhancer marks H3K4me1 and H3K27ac. Here, loss of H3R2me2a results in reduced KMT2D binding and H3K4me1/H3K27ac deposition together with decreased transcription of associated genes, indicating that H3R2me2a also exerts activation functions. Our work suggests that PRMT6 via H3R2me2a interferes with the deposition of adjacent histone marks and modulates the activity of important differentiation-associated genes by opposing transcriptional effects.

MYB induces the expression of the oncogenic corepressor SKI in acute myeloid leukemia.

Acute myeloid leukemia (AML) arises through clonal expansion of transformed myeloid progenitor cells. The SKI proto-oncogene is highly upregulated in different solid tumors and leukemic cells, but little is known about its transcriptional regulation during leukemogenesis. MYB is an important hematopoietic transcription factor involved in proliferation as well as differentiation and upregulated in most human acute leukemias. Here, we find that MYB protein binds within the regulatory region of the SKI gene in AML cells. Reporter gene assays using MYB binding sites present in the SKI gene locus show MYB-dependent transcriptional activation. SiRNA-mediated depletion of MYB in leukemic cell lines reveals that MYB is crucial for SKI gene expression. Consistently, we observed a positive correlation of MYB and SKI expression in leukemic cell lines and in samples of AML patients. Moreover, MYB and SKI both were downregulated by treatment with histone deacetylase inhibitors. Strikingly, differentiation of AML cells induced by depletion of MYB is attenuated by overexpression of SKI. Our findings identify SKI as a novel MYB target gene, relevant for the MYB-induced differentiation block in leukemic cells.

Identification and in silico structural analysis of Gallus gallus protein arginine methyltransferase 4 (PRMT4).

Protein arginine methyltransferase 4 (PRMT4) is an essential epigenetic regulator of fundamental and conserved processes during vertebrate development, such as pluripotency and differentiation. Surprisingly, PRMT4 homologs have been identified in nearly all vertebrate classes except the avian genome. This raises the possibility that in birds PRMT4 functions are taken over by other PRMT family members. Here, we reveal the existence of a bona fide PRMT4 homolog in the chicken, Gallus gallus. Using a biochemical approach, we initially purified a putative chicken PRMT4 protein and thus provided the first evidence for the presence of an endogenous PRMT4-specific enzymatic activity toward histone H3 arginine 17 (H3R17) in avian cells. We then isolated a G. gallus PRMT4 (ggPRMT4) transcript encompassing the complete open reading frame. Recombinant ggPRMT4 possesses intrinsic methyltransferase activity toward H3R17. CRISPR/Cas9-mediated deletion of ggPRMT4 demonstrated that the transcript identified here encodes avian PRMT4. Combining protein-protein docking and homology modeling based on published crystal structures of murine PRMT4, we found a strong structural similarity of the catalytic core domain between chicken and mammalian PRMT4. Strikingly, in silico structural comparison of the N-terminal Pleckstrin homology (PH) domain of avian and murine PRMT4 identified strictly conserved amino acids that are involved in an interaction interface toward the catalytic core domain, facilitating for the first time a prediction of the relative spatial arrangement of these two domains. Our novel findings are particularly exciting in light of the essential function of the PH domain in substrate recognition and methylation by PRMT4.

Comprehension of Inferences in a Narrative in 3- to 6-Year-Old Children.

Purpose: This study aimed to describe the development of inferential abilities of children age 3 to 6 years in a narrative using a dialogic reading task on an iPad. Method: Participants were 121 typically developing children, divided into 3 groups according to age range (3-4 years old, 4-5 years old, 5-6 years old). Total score of inferential comprehension, subscores by causal inference type targeting elements of the story grammar, and quality of response were examined across groups. Results: Inferential comprehension emerged early, from 3 to 4 years old, with considerable interindividual variability. Inferential comprehension scores increased significantly in relation to age, leading to developmental steps with regards to the type of causal inferences. The ability to infer the problem of the story, the internal response of a character, and predictions were easier starting at age 4 years. Then, the 5- to 6-year-olds were better able to infer the goal, the attempt to solve the problem, and the resolution. Last, between the ages of 3 and 6 years, children improved in terms of the quality of response they provided. Conclusion: This study addresses important gaps in our knowledge of inferential comprehension in young children and has implications for planning of early education in this realm.

The Arginine Methyltransferase PRMT6 Cooperates with Polycomb Proteins in Regulating HOXA Gene Expression.

Protein arginine methyltransferase 6 (PRMT6) catalyses asymmetric dimethylation of histone H3 at arginine 2 (H3R2me2a), which has been shown to impede the deposition of histone H3 lysine 4 trimethylation (H3K4me3) by blocking the binding and activity of the MLL1 complex. Importantly, the genomic occurrence of H3R2me2a has been found to coincide with histone H3 lysine 27 trimethylation (H3K27me3), a repressive histone mark generated by the Polycomb repressive complex 2 (PRC2). Therefore, we investigate here a putative crosstalk between PRMT6- and PRC-mediated repression in a cellular model of neuronal differentiation. We show that PRMT6 and subunits of PRC2 as well as PRC1 are bound to the same regulatory regions of rostral HOXA genes and that they control the differentiation-associated activation of these genes. Furthermore, we find that PRMT6 interacts with subunits of PRC1 and PRC2 and that depletion of PRMT6 results in diminished PRC1/PRC2 and H3K27me3 occupancy and in increased H3K4me3 levels at these target genes. Taken together, our data uncover a novel, additional mechanism of how PRMT6 contributes to gene repression by cooperating with Polycomb proteins.