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BioPAN: a web-based tool to explore mammalian lipidome metabolic pathways on LIPID MAPS.
Gaud C, C Sousa B, Nguyen A, Fedorova M, Ni Z, O Donnell VB, Wakelam MJO, Andrews S, Lopez-Clavijo AF
Lipidomics increasingly describes the quantitation using mass spectrometry of all lipids present in a biological sample. As the power of lipidomics protocols increase, thousands of lipid molecular species from multiple categories can now be profiled in a single experiment. Observed changes due to biological differences often encompass large numbers of structurally-related lipids, with these being regulated by enzymes from well-known metabolic pathways. As lipidomics datasets increase in complexity, the interpretation of their results becomes more challenging. BioPAN addresses this by enabling the researcher to visualise quantitative lipidomics data in the context of known biosynthetic pathways. BioPAN provides a list of genes, which could be involved in the activation or suppression of enzymes catalysing lipid metabolism in mammalian tissues.
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F1000Research,
10,
1,
2021
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Histone modifications form a cell-type-specific chromosomal bar code that persists through the cell cycle.
Halsall JA, Andrews S, Krueger F, Rutledge CE, Ficz G, Reik W, Turner BM
Chromatin configuration influences gene expression in eukaryotes at multiple levels, from individual nucleosomes to chromatin domains several Mb long. Post-translational modifications (PTM) of core histones seem to be involved in chromatin structural transitions, but how remains unclear. To explore this, we used ChIP-seq and two cell types, HeLa and lymphoblastoid (LCL), to define how changes in chromatin packaging through the cell cycle influence the distributions of three transcription-associated histone modifications, H3K9ac, H3K4me3 and H3K27me3. We show that chromosome regions (bands) of 10-50 Mb, detectable by immunofluorescence microscopy of metaphase (M) chromosomes, are also present in G and G. They comprise 1-5 Mb sub-bands that differ between HeLa and LCL but remain consistent through the cell cycle. The same sub-bands are defined by H3K9ac and H3K4me3, while H3K27me3 spreads more widely. We found little change between cell cycle phases, whether compared by 5 Kb rolling windows or when analysis was restricted to functional elements such as transcription start sites and topologically associating domains. Only a small number of genes showed cell-cycle related changes: at genes encoding proteins involved in mitosis, H3K9 became highly acetylated in GM, possibly because of ongoing transcription. In conclusion, modified histone isoforms H3K9ac, H3K4me3 and H3K27me3 exhibit a characteristic genomic distribution at resolutions of 1 Mb and below that differs between HeLa and lymphoblastoid cells but remains remarkably consistent through the cell cycle. We suggest that this cell-type-specific chromosomal bar-code is part of a homeostatic mechanism by which cells retain their characteristic gene expression patterns, and hence their identity, through multiple mitoses.
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Scientific reports,
11,
1,
04 Feb 2021
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High-resolution three-dimensional chromatin profiling of the Chinese hamster ovary cell genome.
Bevan S, Schoenfelder S, Young RJ, Zhang L, Andrews S, Fraser P, O'Callaghan PM
Chinese hamster ovary (CHO) cell lines are the pillars of a multi-billion dollar biopharmaceutical industry producing recombinant therapeutic proteins. The effects of local chromatin organisation and epigenetic repression within these cell lines result in unpredictable and unstable transgene expression following random integration. Limited knowledge of the CHO genome and its higher-order chromatin organisation has thus far impeded functional genomics approaches required to tackle these issues. Here, we present an integrative three-dimensional (3D) map of genome organisation within the CHOK1SV® 10E9 cell line in conjunction with an improved, less fragmented CHOK1SV® 10E9 genome assembly. Using our high-resolution chromatin conformation datasets, we have assigned ≈ 90% of sequence to a chromosome-scale genome assembly. Our genome-wide 3D map identifies higher-order chromatin structures such as topologically associated domains, incorporates our chromatin accessibility data to enhance the identification of active cis-regulatory elements and importantly links these cis-regulatory elements to target promoters in a 3D promoter interactome. We demonstrate the power of our improved functional annotation by evaluating the 3D landscape of a transgene integration site and two phenotypically different cell lines. Our work opens up further novel genome engineering targets, has the potential to inform vital improvements for industrial biotherapeutic production, and represents a significant advancement for CHO cell line development. This article is protected by copyright. All rights reserved.
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Biotechnology and bioengineering,
1,
1,
23 Oct 2020
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