Stem cell plasticity, acetylation of H3K14, and de novo gene activation rely on KAT7.

In the conventional model of transcriptional activation, transcription factors bind to response elements and recruit co-factors, including histone acetyltransferases. Contrary to this model, we show that the histone acetyltransferase KAT7 (HBO1/MYST2) is required genome wide for histone H3 lysine 14 acetylation (H3K14ac). Examining neural stem cells, we find that KAT7 and H3K14ac are present not only at transcribed genes but also at inactive genes, intergenic regions, and in heterochromatin. KAT7 and H3K14ac were not required for the continued transcription of genes that were actively transcribed at the time of loss of KAT7 but indispensable for the activation of repressed genes. The absence of KAT7 abrogates neural stem cell plasticity, diverse differentiation pathways, and cerebral cortex development. Re-expression of KAT7 restored stem cell developmental potential. Overexpression of KAT7 enhanced neuron and oligodendrocyte differentiation. Our data suggest that KAT7 prepares chromatin for transcriptional activation and is a prerequisite for gene activation.

Mass Dynamics 1.0: A Streamlined, Web-Based Environment for Analyzing, Sharing, and Integrating Label-Free Data.

Label-free quantification (LFQ) of shotgun proteomics data is a popular and robust method for the characterization of relative protein abundance between samples. Many analytical pipelines exist for the automation of this analysis, and some tools exist for the subsequent representation and inspection of the results of these pipelines. Mass Dynamics 1.0 (MD 1.0) is a web-based analysis environment that can analyze and visualize LFQ data produced by software such as MaxQuant. Unlike other tools, MD 1.0 utilizes a cloud-based architecture to enable researchers to store their data, enabling researchers to not only automatically process and visualize their LFQ data but also annotate and share their findings with collaborators and, if chosen, to easily publish results to the community. With a view toward increased reproducibility and standardization in proteomics data analysis and streamlining collaboration between researchers, MD 1.0 requires minimal parameter choices and automatically generates quality control reports to verify experiment integrity. Here, we demonstrate that MD 1.0 provides reliable results for protein expression quantification, emulating Perseus on benchmark datasets over a wide dynamic range. The MD 1.0 platform is available globally via: https://app.massdynamics.com/.

Finding a suitable library size to call variants in RNA-Seq.

BACKGROUND: RNA sequencing allows the study of both gene expression changes and transcribed mutations, providing a highly effective way to gain insight into cancer biology. When planning the sequencing of a large cohort of samples, library size is a fundamental factor affecting both the overall cost and the quality of the results. Here we specifically address how overall library size influences the detection of somatic mutations in RNA-seq data in two acute myeloid leukaemia datasets. RESULTS : We simulated shallower sequencing depths by downsampling 45 acute myeloid leukaemia samples (100 bp PE) that are part of the Leucegene project, which were originally sequenced at high depth. We compared the sensitivity of six methods of recovering validated mutations on the same samples. The methods compared are a combination of three popular callers (MuTect, VarScan, and VarDict) and two filtering strategies. We observed an incremental loss in sensitivity when simulating libraries of 80M, 50M, 40M, 30M and 20M fragments, with the largest loss detected with less than 30M fragments (below 90%, average loss of 7%). The sensitivity in recovering insertions and deletions varied markedly between callers, with VarDict showing the highest sensitivity (60%). Single nucleotide variant sensitivity is relatively consistent across methods, apart from MuTect, whose default filters need adjustment when using RNA-Seq. We also analysed 136 RNA-Seq samples from the TCGA-LAML cohort (50 bp PE) and assessed the change in sensitivity between the initial libraries (average 59M fragments) and after downsampling to 40M fragments. When considering single nucleotide variants in recurrently mutated myeloid genes we found a comparable performance, with a 6% average loss in sensitivity using 40M fragments. CONCLUSIONS: Between 30M and 40M 100 bp PE reads are needed to recover 90-95% of the initial variants on recurrently mutated myeloid genes. To extend this result to another cancer type, an exploration of the characteristics of its mutations and gene expression patterns is suggested.

Genome-wide analyses identify common variants associated with macular telangiectasia type 2.

Idiopathic juxtafoveal retinal telangiectasis type 2 (macular telangiectasia type 2; MacTel) is a rare neurovascular degenerative retinal disease. To identify genetic susceptibility loci for MacTel, we performed a genome-wide association study (GWAS) with 476 cases and 1,733 controls of European ancestry. Genome-wide significant associations (P < 5 × 10-8) were identified at three independent loci (rs73171800 at 5q14.3, P = 7.74 × 10-17; rs715 at 2q34, P = 9.97 × 10-14; rs477992 at 1p12, P = 2.60 × 10-12) and then replicated (P < 0.01) in an independent cohort of 172 cases and 1,134 controls. The 5q14.3 locus is known to associate with variation in retinal vascular diameter, and the 2q34 and 1p12 loci have been implicated in the glycine/serine metabolic pathway. We subsequently found significant differences in blood serum levels of glycine (P = 4.04 × 10-6) and serine (P = 2.48 × 10-4) between MacTel cases and controls.

Musculoskeletal pain in Europe: the role of personal, occupational, and social risk factors.

OBJECTIVES: The prevalence of musculoskeletal pain in European countries varies considerably. We analyzed data from the fifth European Working Conditions Survey (EWCS) to explore the role of personal, occupational, and social risk factors in determining the national prevalence of musculoskeletal pain. METHODS: Over the course of 2010, 43 816 subjects from 34 countries were interviewed. We analyzed the one-year prevalence of back and neck/upper-limb pain. Individual-level risk factors studied included: sex; age; educational level; socioeconomic status; housework or cooking; gardening and repairs; somatizing tendency; job demand-control; six physical occupational exposures; and occupational group. Data on national socioeconomic variables were obtained from Eurostat and were available for 28 countries. We fitted Poisson regression models with random intercept by country. RESULTS: The main analysis comprised 35 550 workers. Among individual-level risk factors, somatizing tendency was the strongest predictor of the symptoms. Major differences were observed by country with back pain more than twice as common in Portugal (63.8%) than Ireland (25.7%), and prevalence rates of neck/upper-limb pain ranging from 26.6% in Ireland to 67.7% in Finland. Adjustment for individual-level risk factors slightly reduced the large variation in prevalence between countries. For back pain, the rates were more homogenous after adjustment for national socioeconomic variables. CONCLUSIONS: Our analysis indicates substantial variation between European countries in the prevalence of back and neck/upper-limb pain. This variation is unexplained by established individual risk factors. It may be attributable in part to socioeconomic differences between countries, with higher prevalence where there is less risk of poverty or social exclusion.