A fast Myh super enhancer dictates adult muscle fiber phenotype through competitive interactions with the fast Myh genes
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ABSTRACT:
PROVIDER: PRJNA705988 | ENA |
REPOSITORIES: ENA
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Project description:The contractile properties of adult myofibers are shaped by their Myosin heavy chain (MYH) isoform content. We identify by snATAC-seq a 42kb super-enhancer (SE) at the locus regrouping the fast Myh (fMyh) genes. By 4C-seq we show that active fMyh promoters interact with the SE by DNA looping, leading to the activation of a single promoter per nucleus. A rainbow mouse transgenic model of the locus including the SE recapitulates the endogenous spatio-temporal expression of adult fMyh genes. In situ deletion of the SE by CRISPR/Cas9 editing demonstrates its major role in the control of associated fMyh genes, and deletion of two fMyh genes at the locus reveals an active competition of the promoters for the shared SE. Last, by disrupting the organization of fMyh, we uncover positional heterogeneity within limb skeletal muscles that may underlie selective muscle susceptibility to damage in certain myopathies.
2021-12-17 | GSE168074 | GEO
Project description:Thousands of long intergenic noncoding RNAs (lincRNAs) are encoded by the mammalian genome, which were reported to have multiple biological functions as transcriptional activators acting in cis 1 or trans 2, transcriptional repressors 3,4 or miRNAs decoys 5,6. However, the function of most lincRNAs has not yet been identified in vivo. Here, we demonstrate a role for linc-MYH, a novel long intergenic noncoding RNA, in adult fast-type myofibre specialization. Skeletal myofibre fast and slow phenotypes are established through differential expression of numerous fibre-specific genes7. We show linc-MYH and the fast MYH genes share a common enhancer located in the fast MYH genes locus and regulated by the Six1 homeoproteins. Muscle-specific Six1 mutant mice show increased expression of slow-type genes, and downregulation of linc-MYH and fast-type genes. linc-MYH function revealed by in vivo knockdown and wide transcriptomic analysis, is in fine to prevent expression of genes ensuring slow muscle contractile properties, and to increase fast-type muscle gene expression in fast-type myofibres. Thus, formation of efficient fast sarcomeric units and appropriate Ca++ cycling and excitation/contraction/relaxation coupling in fast- myofibres is achieved through the coordiante control of fast MYHs and linc-MYH expression by a Six bound enhancer.
2014-04-27 | GSE46151 | GEO
Project description:Thousands of long intergenic noncoding RNAs (lincRNAs) are encoded by the mammalian genome, which were reported to have multiple biological functions as transcriptional activators acting in cis 1 or trans 2, transcriptional repressors 3,4 or miRNAs decoys 5,6. However, the function of most lincRNAs has not yet been identified in vivo. Here, we demonstrate a role for linc-MYH, a novel long intergenic noncoding RNA, in adult fast-type myofibre specialization. Skeletal myofibre fast and slow phenotypes are established through differential expression of numerous fibre-specific genes7. We show linc-MYH and the fast MYH genes share a common enhancer located in the fast MYH genes locus and regulated by the Six1 homeoproteins. Muscle-specific Six1 mutant mice show increased expression of slow-type genes, and downregulation of linc-MYH and fast-type genes. linc-MYH function revealed by in vivo knockdown and wide transcriptomic analysis, is in fine to prevent expression of genes ensuring slow muscle contractile properties, and to increase fast-type muscle gene expression in fast-type myofibres. Thus, formation of efficient fast sarcomeric units and appropriate Ca++ cycling and excitation/contraction/relaxation coupling in fast- myofibres is achieved through the coordiante control of fast MYHs and linc-MYH expression by a Six bound enhancer. Ten μg of shRNA-expressing vector were introduced into TA muscles of 8 week-old mice by electroporation. Two weeks following electroporation, TA myofibres expressing GFP were dissected under a Nikon SMZ1500 stereo microscope and frozen in liquid nitrogen before processing. The efficiency of each shRNA was established by determination of linc-MYH transcript levels in TA muscles transfected by each shlincMYH. The shRNA against 5'- TTCTGCTCACCACCTACAATT-3' sequence was selected for the knockdown experiment. After validation of RNA quality with the Bioanalyzer 2100 (using Agilent RNA6000 nano chip kit), 50 ng of total RNA were reverse transcribed following the Ovation PicoSL WTA System (Nugen). Briefly, the resulting double-strand cDNA was used for amplification based on SPIA technology. After purification according to Nugen protocol, 5 μg of single strand DNA was used for generation of Sens Target DNA using Ovation Exon Module kit (Nugen). 2.5 μg of Sens Target DNA were fragmented and labelled with biotin using Encore Biotin Module kit (Nugen). After control of fragmentation using Bioanalyzer 2100, the cDNA was then hybridized to GeneChip® Mouse Gene 1.0 ST (Affymetrix) at 45°C for 17 hours. After overnight hybridization, the ChIPs were washed using the fluidic station FS450 following specific protocols (Affymetrix) and scanned using the GCS3000 7G. The scanned images were then analyzed with Expression Console software (Affymetrix) to obtain raw data (cel files) and metrics for Quality Controls. The analysis of some of these metrics and the study of the distribution of raw data show no outlier experiment. Gastrocnemius muscles were collected from cSix1 KO and control mice. Total RNAs were extracted by Trizol Reagent (Invitrogen) according to manufacturer's instruction. After validation of RNA quality with the Bioanalyzer 2100 (using Agilent RNA6000 nano chip kit), 50 ng of total RNA were reverse transcribed following the Ovation PicoSL WTA System (Nugen). Briefly, the resulting double-strand cDNA was used for amplification based on SPIA technology. After purification according to Nugen protocol, 5 μg of single strand DNA was used for generation of Sens Target DNA using Ovation Exon Module kit (Nugen). 2.5 μg of Sens Target DNA were fragmented and labelled with biotin using Encore Biotin Module kit (Nugen). After control of fragmentation using Bioanalyzer 2100, the cDNA was then hybridized to GeneChip® Mouse Gene 1.0 ST (Affymetrix) at 45°C for 17 hours. After overnight hybridization, the ChIPs were washed using the fluidic station FS450 following specific protocols (Affymetrix) and scanned using the GCS3000 7G. The scanned images were then analyzed with Expression Console software (Affymetrix) to obtain raw data (cel files) and metrics for Quality Controls. The analysis of some of these metrics and the study of the distribution of raw data show no outlier experiment.
2014-04-27 | E-GEOD-46151 | biostudies-arrayexpress
Project description:Skeletal muscle is a key tissue in human aging, which affects different muscle fiber types unequally. We developed a highly sensitive single muscle fiber proteomics workflow to study human aging and show that the senescence of slow and fast muscle fibers is characterized by diverging metabolic and protein quality control adaptations. Whereas mitochondrial content declines with aging in both fiber types, glycolysis and glycogen metabolism are upregulated in slow but downregulated in fast muscle fibers. Aging mitochondria decrease expression of the redox enzyme monoamine oxidase A. Slow fibers upregulate a subset of actin and myosin chaperones, whereas an opposite change happens in fast fibers. These changes in metabolism and sarcomere quality control may be related to the ability of slow, but not fast, muscle fibers to maintain their mass during aging. We conclude that single muscle fiber analysis by proteomics can elucidate pathophysiology in a sub-type specific manner.
2017-06-14 | PXD006182 | Pride
Project description:To get glance to the events of the fast elongation and second cell wall synthesis stages of developing cotton fiber cells, we examined expression patterns of over 5000 genes by cDNA array from 3 to 18 DPA in a 3-day interval. RNAs from the 3-, 6-, 9-, 12-, 15-, and 18-DPA fibers were compared to the 9-DPA fiber RNA for time-course analysis. Four biological repeats were carried out including two dye-swap ones.
2006-04-12 | E-GEOD-4639 | biostudies-arrayexpress
Project description:Six homeoproteins regulate fast MYH expression and calcium homeostasis
2016-08-23 | GSE50023 | GEO
Project description:To get glance to the events of the fast elongation and second cell wall synthesis stages of developing cotton fiber cells, we examined expression patterns of over 5000 genes by cDNA array from 3 to 18 DPA in a 3-day interval. Keywords: Time Course
2006-04-12 | GSE4639 | GEO
Project description:Skeletal muscle is highly developed after birth, consisting of glycolytic fast- and oxidative slow-twitch fibers; however, the mechanisms of fiber type-specific differentiation are poorly understood. Here, we found an unexpected role for mitochondrial fission in the differentiation of fast-twitch oxidative fibers. Depletion of the mitochondrial fission factor dynamin-related protein 1 (Drp1) in mouse skeletal muscle and cultured myotubes resulted in the specific reduction of fast-twitch muscle fibers independently of respiratory function. Altered mitochondrial fission caused the activation of the Akt/mammalian target of rapamycin (mTOR) pathway via the mitochondrial accumulation of mTOR complex 2 (mTORC2), and rapamycin administration rescued the reduction of fast-twitch fibers in vivo and in vitro. Under Akt/mTOR activation, the mitochondria-related cytokine growth differentiation factor-15 was upregulated, which repressed fast-twitch fiber differentiation. Our findings reveal a novel role for mitochondrial dynamics in the activation of mTORC2 on mitochondria, resulting in the differentiation of muscle fibers.
2023-04-01 | GSE228362 | GEO
Project description:Skeletal muscle plays an important role in the health-promoting effects of exercise training, yet the underlying mechanisms are not fully elucidated. Proteomics of skeletal muscle is challenging due to presence of non-muscle tissues and existence of different fiber types confounding the results. This can be circumvented by analysis of pure fibers; however this requires isolation of fibers from fresh tissues. We developed a workflow enabling proteomics analysis of isolated muscle fibers from freeze-dried muscle biopsies and identified >4000 proteins. We investigated effects of exercise training on the pool of slow and fast muscle fibers. Exercise altered expression of >500 proteins irrespective of fiber type covering several metabolic processes, mainly related to mitochondria. Furthermore, exercise training altered proteins involved in regulation of post-translational modifications, transcription, Ca++ signaling, fat, and glucose metabolism in a fiber type-specific manner. Our data serves as a valuable resource for elucidating molecular mechanisms underlying muscle performance and health. Finally, our workflow offers methodological advancement allowing proteomic analyses of already stored freeze-dried human muscle biopsies.
2020-12-21 | PXD012824 | Pride