Notch signalling in context.

The highly conserved Notch signalling pathway functions in many different developmental and homeostatic processes, which raises the question of how this pathway can achieve such diverse outcomes. With a direct route from the membrane to the nucleus, the Notch pathway has fewer opportunities for regulation than do many other signalling pathways, yet it generates exquisitely patterned structures, including sensory hair cells and branched arterial networks. More confusingly, its activity promotes tissue growth and cancers in some circumstances but cell death and tumour suppression in others. Many different regulatory mechanisms help to shape the activity of the Notch pathway, generating functional outputs that are appropriate for each context. These mechanisms include the receptor-ligand landscape, the tissue topology, the nuclear environment and the connectivity of the regulatory networks.

OptIC-Notch reveals mechanism that regulates receptor interactions with CSL.

Active Notch signalling is elicited through receptor-ligand interactions that result in release of the Notch intracellular domain (NICD), which translocates into the nucleus. NICD activates transcription at target genes, forming a complex with the DNA-binding transcription factor CSL [CBF1/Su(H)/LAG-1] and co-activator Mastermind. However, CSL lacks its own nuclear localisation sequence, and it remains unclear where the tripartite complex is formed. To probe the mechanisms involved, we designed an optogenetic approach to control NICD release (OptIC-Notch) and monitored the subsequent complex formation and target gene activation. Strikingly, we observed that, when uncleaved, OptIC-Notch sequestered CSL in the cytoplasm. Hypothesising that exposure of a juxta membrane ΦWΦP motif is key to sequestration, we masked this motif with a second light-sensitive domain (OptIC-Notch{ω}), which was sufficient to prevent CSL sequestration. Furthermore, NICD produced by light-induced cleavage of OptIC-Notch or OptIC-Notch{ω} chaperoned CSL into the nucleus and induced target gene expression, showing efficient light-controlled activation. Our results demonstrate that exposure of the ΦWΦP motif leads to CSL recruitment and suggest this can occur in the cytoplasm prior to nuclear entry.

Mechanisms underlying the cooperation between loss of epithelial polarity and Notch signaling during neoplastic growth in Drosophila.

Aggressive neoplastic growth can be initiated by a limited number of genetic alterations, such as the well-established cooperation between loss of cell architecture and hyperactive signaling pathways. However, our understanding of how these different alterations interact and influence each other remains very incomplete. Using Drosophila paradigms of imaginal wing disc epithelial growth, we have monitored the changes in Notch pathway activity according to the polarity status of cells (scrib mutant). We show that the scrib mutation impacts the direct transcriptional output of the Notch pathway, without altering the global distribution of Su(H), the Notch-dedicated transcription factor. The Notch-dependent neoplasms require, however, the action of a group of transcription factors, similar to those previously identified for Ras/scrib neoplasm (namely AP-1, Stat92E, Ftz-F1 and basic leucine zipper factors), further suggesting the importance of this transcription factor network during neoplastic growth. Finally, our work highlights some Notch/scrib specificities, in particular the role of the PAR domain-containing basic leucine zipper transcription factor and Notch direct target Pdp1 for neoplastic growth.

Membrane architecture and adherens junctions contribute to strong Notch pathway activation.

The Notch pathway mediates cell-to-cell communication in a variety of tissues, developmental stages and organisms. Pathway activation relies on the interaction between transmembrane ligands and receptors on adjacent cells. As such, pathway activity could be influenced by the size, composition or dynamics of contacts between membranes. The initiation of Notch signalling in the Drosophila embryo occurs during cellularization, when lateral cell membranes and adherens junctions are first being deposited, allowing us to investigate the importance of membrane architecture and specific junctional domains for signalling. By measuring Notch-dependent transcription in live embryos, we established that it initiates while lateral membranes are growing and that signalling onset correlates with a specific phase in their formation. However, the length of the lateral membranes per se was not limiting. Rather, the adherens junctions, which assemble concurrently with membrane deposition, contributed to the high levels of signalling required for transcription, as indicated by the consequences of α-Catenin depletion. Together, these results demonstrate that the establishment of lateral membrane contacts can be limiting for Notch trans-activation and suggest that adherens junctions play an important role in modulating Notch activity.

The conserved C2 phospholipid-binding domain in Delta contributes to robust Notch signalling.

Accurate Notch signalling is critical for development and homeostasis. Fine-tuning of Notch-ligand interactions has substantial impact on signalling outputs. Recent structural studies have identified a conserved N-terminal C2 domain in human Notch ligands which confers phospholipid binding in vitro. Here, we show that Drosophila ligands Delta and Serrate adopt the same C2 domain structure with analogous variations in the loop regions, including the so-called ß1-2 loop that is involved in phospholipid binding. Mutations in the ß1-2 loop of the Delta C2 domain retain Notch binding but have impaired ability to interact with phospholipids in vitro. To investigate its role in vivo, we deleted five residues within the ß1-2 loop of endogenous Delta. Strikingly, this change compromises ligand function. The modified Delta enhances phenotypes produced by Delta loss-of-function alleles and suppresses that of Notch alleles. As the modified protein is present on the cell surface in normal amounts, these results argue that C2 domain phospholipid binding is necessary for robust signalling in vivo fine-tuning the balance of trans and cis ligand-receptor interactions.

Implications of ACC/AHA Versus ESC/EAS LDL-C Recommendations for Residual Risk Reduction in ASCVD: A Simulation Study From DA VINCI.

PURPOSE: Low-density lipoprotein cholesterol (LDL-C) recommendations differ between the 2018 American College of Cardiology/American Heart Association (ACC/AHA) and 2019 European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) guidelines for patients with atherosclerotic cardiovascular disease (ASCVD) (< 70 vs. < 55 mg/dl, respectively). In the DA VINCI study, residual cardiovascular risk was predicted in ASCVD patients. The extent to which relative and absolute risk might be lowered by achieving ACC/AHA versus ESC/EAS LDL-C recommended approaches was simulated. METHODS: DA VINCI was a cross-sectional observational study of patients prescribed lipid-lowering therapy (LLT) across 18 European countries. Ten-year cardiovascular risk (CVR) was predicted among ASCVD patients receiving stabilized LLT. For patients with LDL-C ≥ 70 mg/dl, the absolute LDL-C reduction required to achieve an LDL-C of < 70 or < 55 mg/dl (LDL-C of 69 or 54 mg/dl, respectively) was calculated. Relative and absolute risk reductions (RRRs and ARRs) were simulated. RESULTS: Of the 2039 patients, 61% did not achieve LDL-C < 70 mg/dl. For patients with LDL-C ≥ 70 mg/dl, median (interquartile range) baseline LDL-C and 10-year CVR were 93 (81-115) mg/dl and 32% (25-43%), respectively. Median LDL-C reductions of 24 (12-46) and 39 (27-91) mg/dl were needed to achieve an LDL-C of 69 and 54 mg/dl, respectively. Attaining ACC/AHA or ESC/EAS goals resulted in simulated RRRs of 14% (7-25%) and 22% (15-32%), respectively, and ARRs of 4% (2-7%) and 6% (4-9%), respectively. CONCLUSION: In ASCVD patients, achieving ESC/EAS LDL-C goals could result in a 2% additional ARR over 10 years versus the ACC/AHA approach.

Lions and brown bears colonized North America in multiple synchronous waves of dispersal across the Bering Land Bridge.

The Bering Land Bridge connecting North America and Eurasia was periodically exposed and inundated by oscillating sea levels during the Pleistocene glacial cycles. This land connection allowed the intermittent dispersal of animals, including humans, between Western Beringia (far northeast Asia) and Eastern Beringia (northwest North America), changing the faunal community composition of both continents. The Pleistocene glacial cycles also had profound impacts on temperature, precipitation and vegetation, impacting faunal community structure and demography. While these palaeoenvironmental impacts have been studied in many large herbivores from Beringia (e.g., bison, mammoths, horses), the Pleistocene population dynamics of the diverse guild of carnivorans present in the region are less well understood, due to their lower abundances. In this study, we analyse mitochondrial genome data from ancient brown bears (Ursus arctos; n = 103) and lions (Panthera spp.; n = 39), two megafaunal carnivorans that dispersed into North America during the Pleistocene. Our results reveal striking synchronicity in the population dynamics of Beringian lions and brown bears, with multiple waves of dispersal across the Bering Land Bridge coinciding with glacial periods of low sea levels, as well as synchronous local extinctions in Eastern Beringia during Marine Isotope Stage 3. The evolutionary histories of these two taxa underline the crucial biogeographical role of the Bering Land Bridge in the distribution, turnover and maintenance of megafaunal populations in North America.

SWI/SNF chromatin remodeling controls Notch-responsive enhancer accessibility.

Notch signaling plays a key role in many cell fate decisions during development by directing different gene expression programs via the transcription factor CSL, known as Su(H) in Drosophila Which target genes are responsive to Notch signaling is influenced by the chromatin state of enhancers, yet how this is regulated is not fully known. Detecting a specific increase in the histone variant H3.3 in response to Notch signaling, we tested which chromatin remodelers or histone chaperones are required for the changes in enhancer accessibility to Su(H) binding. We show a crucial role for the Brahma SWI/SNF chromatin remodeling complex, including the actin-related BAP55 subunit, in conferring enhancer accessibility and enabling the transcriptional response to Notch activity. The Notch-responsive regions have high levels of nucleosome turnover which depend on the Brahma complex, increase in magnitude with Notch signaling, and primarily involve histone H3.3. Together these results highlight the importance of SWI/SNF-mediated nucleosome turnover in rendering enhancers responsive to Notch.

Health status and healthcare trends of individuals accessing Australian aged care programmes over a decade: the Registry of Senior Australians historical cohort.

BACKGROUND: Understanding the health profile, service and medicine use of Australians in the aged care sector will help inform appropriate service provision for our ageing population. AIMS: To examine the 2006-2015 trends in (i) comorbidities and frailty of individuals accessing aged care, and (ii) health services, medicine use and mortality after entry into long-term care. METHODS: Cross-sectional and population-based trend analyses were conducted using the Registry of Senior Australians. RESULTS: From 2006 to 2015, 509 944 individuals accessed permanent residential care, 206 394 home care, 283 014 respite and 124 943 transition care. Over this time, the proportion of individuals accessing permanent residential care with high frailty scores (≥0.3) increased (19.7-49.7%), as did the proportion with 5-9 comorbidities (46.4-54.5%), with similar trends observed for those accessing other services. The median number of medicines dispensed in the year after entering permanent residential care increased from 9 (interquartile range (IQR) 6-12) to 10 (IQR 7-14), while remaining stable in home care (2006: 9, IQR 5-12, 2015: 9, IQR 6-13). Short-term (within 100 days) mortality in those accessing permanent care was higher in 2006 (15.6%, 95% CI 15.2-16.0) than 2015 (14.6%, 95% CI 14.3-14.9). Longer term (101-1095 days, 2006: 44.3%, 95% CI 43.7-45.0, 2015: 46.4%, 95% CI 45.8-46.9) mortality was higher in 2015 compared to 2006. Mortality in individuals accessing home care did not change. CONCLUSION: The health of older Australians accessing aged care programmes has declined while frailty increased, with an increasing use of medicine and worse long-term mortality in some. Funding and care models need to adapt to this changing profile.

Genome-wide identification of Grainy head targets in Drosophila reveals regulatory interactions with the POU domain transcription factor Vvl.

Grainy head (Grh) is a conserved transcription factor (TF) controlling epithelial differentiation and regeneration. To elucidate Grh functions we identified embryonic Grh targets by ChIP-seq and gene expression analysis. We show that Grh controls hundreds of target genes. Repression or activation correlates with the distance of Grh-binding sites to the transcription start sites of its targets. Analysis of 54 Grh-responsive enhancers during development and upon wounding suggests cooperation with distinct TFs in different contexts. In the airways, Grh-repressed genes encode key TFs involved in branching and cell differentiation. Reduction of the POU domain TF Ventral veins lacking (Vvl) largely ameliorates the airway morphogenesis defects of grh mutants. Vvl and Grh proteins additionally interact with each other and regulate a set of common enhancers during epithelial morphogenesis. We conclude that Grh and Vvl participate in a regulatory network controlling epithelial maturation.

Evolocumab treatment in patients with HIV and hypercholesterolemia/mixed dyslipidemia: BEIJERINCK study design and baseline characteristics.

BACKGROUND: People living with human immunodeficiency virus (PLHIV) are at higher risk of atherosclerotic cardiovascular disease (ASCVD) due to traditional and HIV- or antiretroviral treatment (ART)-related risk factors. The use of high-intensity statin therapy is often limited by comorbidities and drug-drug interactions with ART. Herein, we present the design and baseline characteristics of the BEIJERINCK study, which will assess the safety and efficacy of evolocumab in PLHIV and hypercholesterolemia/mixed dyslipidemia. METHODS: Randomized, double-blind, placebo-controlled, multinational trial that investigates monthly subcutaneous evolocumab 420 mg versus placebo in PLHIV with hypercholesterolemia/mixed dyslipidemia who are treated with maximally-tolerated statin therapy. The primary outcome is the baseline to week 24 percent change in low density lipoprotein cholesterol (LDL-C). Secondary outcomes include achievement of LDL-C < 70 mg/dL and percent change in other plasma lipid and lipoprotein levels. Safety will also be examined. RESULTS: This study enrolled and dosed 464 patients who had a mean age of 56.4 years and were mostly male (82.5%). Mean duration with HIV was 17.4 years, and, by design, HIV viral load at screening was ≤50 copies/mL. ASCVD was documented in 35.6% of patients. Mean LDL-C of enrolled patients at baseline was 133.3 mg/dL. Statin use was prevalent (79.3% overall) with 74.6% receiving moderate or high-intensity statins. In total, 20.7% of patients did not receive statins due to intolerance/contraindications. CONCLUSIONS: The BEIJERINCK study is the first clinical trial to examine the lipid-lowering efficacy and safety of a fully human PCSK9 monoclonal antibody inhibitor in a moderate/high cardiovascular risk population of PLHIV.

Decoding the Notch signal.

Notch signalling controls many key cellular processes which differ according to the context where the pathway is deployed due to the transcriptional activation of specific sets of genes. The pathway is unusual in its lack of amplification, also raising the question of how it can efficiently activate transcription with limited amounts of nuclear activity. Here, we focus on mechanisms that enable Notch to produce appropriate transcriptional responses and speculate on models that could explain the current gaps in knowledge.

The prevalence, trends and determinants of mental health disorders in older Australians living in permanent residential aged care: Implications for policy and quality of aged care services.

OBJECTIVE: Mental health disorders are a major health concern in older people and are associated with a higher risk of disability, frailty and early mortality. This study aimed to conduct a contemporary population-based assessment of the prevalence, trends and factors associated with mental health disorders in individuals who are living in permanent residential aged care (PRAC) in Australia. METHODS: A retrospective cross-sectional study was conducted using national data from the Registry of Senior Australians, a national cohort of older Australians who had aged care eligibility assessment and entered PRAC between 2008 and 2016. Stepwise multivariate logistic regression modeling was applied to identify factors associated with mental health disorders. RESULTS: Of 430,862 individuals included in this study, 57.8% had at least one mental health disorder. The prevalence of depression, phobia/anxiety and psychosis were as follows: 46.2% (95% confidence interval = [46.0%, 46.3%]), 14.9% (95% confidence interval = [14.8%, 15.0%]) and 9.7% (95% confidence interval = [9.6%, 9.8%]), respectively. The likelihood of having a mental health disorder was higher for those who were (adjusted odds ratio [95% confidence interval]) relatively younger, specifically for every 10-year increment in age, the odds of having mental health disorders was 44.0% lower (0.56, [0.55, 0.56]); female (1.33 [1.32, 1.35]); having increasing numbers of physical health comorbidities, 6-10 (1.26 [1.24, 1.29]) or 11-15 (1.48 [1.45, 1.51]) or more than 15 (1.64 [1.58, 1.71]) compared to people having less than five comorbidities; having limitations related to health care tasks (1.05 [1.04, 1.07]), meals (1.04 [1.02, 1.05]) or social and community participation (1.10 [1.08, 1.12]). CONCLUSION: The burden of mental health disorders in older Australians living in PRAC was high and individuals with these conditions tend to be younger, with several physical comorbidities and/or functional limitations. Understanding the profile of individuals with mental health disorders at entry into PRAC can be used as evidence for baseline resource allocation for this population and evaluation of future needs of mental health services.

The Registry of Senior Australians outcome monitoring system: quality and safety indicators for residential aged care.

OBJECTIVES: To introduce the Registry of Senior Australians (ROSA) Outcome Monitoring System, which can monitor the quality and safety of care provided to individuals accessing residential aged care. Development and examination of 12 quality and safety indicators of care and their 2016 prevalence estimates are presented. DESIGN: Retrospective. SETTING: 2690 national and 254 South Australian (SA) aged care facilities. PARTICIPANTS: 208 355 unique residents nationally and 18 956 in SA. MAIN OUTCOME MEASURES: Risk-adjusted prevalence of high sedative load, antipsychotic use, chronic opioid use, antibiotic use, premature mortality, falls, fractures, medication-related adverse events, weight loss/malnutrition, delirium and/or dementia hospitalisations, emergency department presentations, and pressure injuries. RESULTS: Five indicators were estimated nationally; antibiotic use (67.5%, 95% confidence interval (CI): 67.3-67.7%) had the highest prevalence, followed by high sedative load (48.1%, 95% CI: 47.9-48.3%), chronic opioid use (26.8%, 95% CI: 26.6-26.9%), antipsychotic use (23.5%, 95% CI: 23.4-23.7%) and premature mortality (0.6%, 95% CI: 0.6-0.7%). Seven indicators were estimated in SA; emergency department presentations (19.1%, 95% CI: 18.3-20.0%) had the highest prevalence, followed by falls (10.1%, 95% CI: 9.7-10.4%), fractures (4.8%, 95% CI: 4.6-5.1%), pressure injuries (2.9%, 95% CI: 2.7-3.1%), delirium and/or dementia related hospitalisations (2.3%, 95% CI: 2.1-2.6%), weight loss/malnutrition (0.7%, 95% CI: 0.6-0.8%) and medication-related events (0.6%, 95% CI: 0.5-0.7%). CONCLUSIONS: Twelve quality and safety indicators were developed to monitor aged care provided to older Australians based on the synthesis of existing literature and expert advisory input. These indicators rely on existing data within the aged care and healthcare sectors, therefore creating a pragmatic tool to examine quality and unwarranted care variation.

Role of co-repressor genomic landscapes in shaping the Notch response.

Repressors are frequently deployed to limit the transcriptional response to signalling pathways. For example, several co-repressors interact directly with the DNA-binding protein CSL and are proposed to keep target genes silenced in the absence of Notch activity. However, the scope of their contributions remains unclear. To investigate co-repressor activity in the context of this well defined signalling pathway, we have analysed the genome-wide binding profile of the best-characterized CSL co-repressor in Drosophila, Hairless, and of a second CSL interacting repressor, SMRTER. As predicted there was significant overlap between Hairless and its CSL DNA-binding partner, both in Kc cells and in wing discs, where they were predominantly found in chromatin with active enhancer marks. However, while the Hairless complex was widely present at some Notch regulated enhancers in the wing disc, no binding was detected at others, indicating that it is not essential for silencing per se. Further analysis of target enhancers confirmed differential requirements for Hairless. SMRTER binding significantly overlapped with Hairless, rather than complementing it, and many enhancers were apparently co-bound by both factors. Our analysis indicates that the actions of Hairless and SMRTER gate enhancers to Notch activity and to Ecdysone signalling respectively, to ensure that the appropriate levels and timing of target gene expression are achieved.

Chromatin signatures at Notch-regulated enhancers reveal large-scale changes in H3K56ac upon activation.

The conserved Notch pathway functions in diverse developmental and disease-related processes, requiring mechanisms to ensure appropriate target selection and gene activation in each context. To investigate the influence of chromatin organisation and dynamics on the response to Notch signalling, we partitioned Drosophila chromatin using histone modifications and established the preferred chromatin conditions for binding of Su(H), the Notch pathway transcription factor. By manipulating activity of a co-operating factor, Lozenge/Runx, we showed that it can help facilitate these conditions. While many histone modifications were unchanged by Su(H) binding or Notch activation, we detected rapid changes in acetylation of H3K56 at Notch-regulated enhancers. This modification extended over large regions, required the histone acetyl-transferase CBP and was independent of transcription. Such rapid changes in H3K56 acetylation appear to be a conserved indicator of enhancer activation as they also occurred at the mammalian Notch-regulated Hey1 gene and at Drosophila ecdysone-regulated genes. This intriguing example of a core histone modification increasing over short timescales may therefore underpin changes in chromatin accessibility needed to promote transcription following signalling activation.

Genes implicated in stem cell identity and temporal programme are directly targeted by Notch in neuroblast tumours.

Notch signalling is involved in a multitude of developmental decisions and its aberrant activation is linked to many diseases, including cancers. One example is the neural stem cell tumours that arise from constitutive Notch activity in Drosophila neuroblasts. To investigate how hyperactivation of Notch in larval neuroblasts leads to tumours, we combined results from profiling the upregulated mRNAs and mapping the regions bound by the core Notch pathway transcription factor Su(H). This identified 246 putative direct Notch targets. These genes were highly enriched for transcription factors and overlapped significantly with a previously identified regulatory programme dependent on the proneural transcription factor Asense. Included were genes associated with the neuroblast maintenance and self-renewal programme that we validated as Notch regulated in vivo. Another group were the so-called temporal transcription factors, which have been implicated in neuroblast maturation. Normally expressed in specific time windows, several temporal transcription factors were ectopically expressed in the stem cell tumours, suggesting that Notch had reprogrammed their normal temporal regulation. Indeed, the Notch-induced hyperplasia was reduced by mutations affecting two of the temporal factors, which, conversely, were sufficient to induce mild hyperplasia on their own. Altogether, the results suggest that Notch induces neuroblast tumours by directly promoting the expression of genes that contribute to stem cell identity and by reprogramming the expression of factors that could regulate maturity.

Drosophila MAGI interacts with RASSF8 to regulate E-Cadherin-based adherens junctions in the developing eye.

Morphogenesis is crucial during development to generate organs and tissues of the correct size and shape. During Drosophila late eye development, interommatidial cells (IOCs) rearrange to generate the highly organized pupal lattice, in which hexagonal ommatidial units pack tightly. This process involves the fine regulation of adherens junctions (AJs) and of adhesive E-Cadherin (E-Cad) complexes. Localized accumulation of Bazooka (Baz), the Drosophila PAR3 homolog, has emerged as a critical step to specify where new E-Cad complexes should be deposited during junction remodeling. However, the mechanisms controlling the correct localization of Baz are still only partly understood. We show here that Drosophila Magi, the sole fly homolog of the mammalian MAGI scaffolds, is an upstream regulator of E-Cad-based AJs during cell rearrangements, and that Magi mutant IOCs fail to reach their correct position. We uncover a direct physical interaction between Magi and the Ras association domain protein RASSF8 through a WW domain-PPxY motif binding, and show that apical Magi recruits the RASSF8-ASPP complex during AJ remodeling in IOCs. We further show that this Magi complex is required for the cortical recruitment of Baz and of the E-Cad-associated proteins α- and ß-catenin. We propose that, by controlling the proper localization of Baz to remodeling junctions, Magi and the RASSF8-ASPP complex promote the recruitment or stabilization of E-Cad complexes at junction sites.

Dissecting the mechanisms of Notch induced hyperplasia.

The outcome of the Notch pathway on proliferation depends on cellular context, being growth promotion in some, including several cancers, and growth inhibition in others. Such disparate outcomes are evident in Drosophila wing discs, where Notch overactivation causes hyperplasia despite having localized inhibitory effects on proliferation. To understand the underlying mechanisms, we have used genomic strategies to identify the Notch-CSL target genes directly activated during wing disc hyperplasia. Among them were genes involved in both autonomous and non-autonomous regulation of proliferation, growth and cell death, providing molecular explanations for many characteristics of Notch induced wing disc hyperplasia previously reported. The Notch targets exhibit different response patterns, which are shaped by both positive and negative feed-forward regulation between the Notch targets themselves. We propose, therefore, that both the characteristics of the direct Notch targets and their cross-regulatory relationships are important in coordinating the pattern of hyperplasia.

Histone chaperones ASF1 and NAP1 differentially modulate removal of active histone marks by LID-RPD3 complexes during NOTCH silencing.

Histone chaperones are involved in a variety of chromatin transactions. By a proteomics survey, we identified the interaction networks of histone chaperones ASF1, CAF1, HIRA, and NAP1. Here, we analyzed the cooperation of H3/H4 chaperone ASF1 and H2A/H2B chaperone NAP1 with two closely related silencing complexes: LAF and RLAF. NAP1 binds RPD3 and LID-associated factors (RLAF) comprising histone deacetylase RPD3, histone H3K4 demethylase LID/KDM5, SIN3A, PF1, EMSY, and MRG15. ASF1 binds LAF, a similar complex lacking RPD3. ASF1 and NAP1 link, respectively, LAF and RLAF to the DNA-binding Su(H)/Hairless complex, which targets the E(spl) NOTCH-regulated genes. ASF1 facilitates gene-selective removal of the H3K4me3 mark by LAF but has no effect on H3 deacetylation. NAP1 directs high nucleosome density near E(spl) control elements and mediates both H3 deacetylation and H3K4me3 demethylation by RLAF. We conclude that histone chaperones ASF1 and NAP1 differentially modulate local chromatin structure during gene-selective silencing.