Myocardin-related transcription factors (MRTFs) play a central role in the regulation of actin expression and cytoskeletal dynamics. Stimuli that promote actin polymerization allow for shuttling of MRTFs to the nucleus where they activate serum response factor (SRF), a regulator of actin and other cytoskeletal protein genes. SRF is an essential regulator of skeletal muscle differentiation and numerous components of the muscle sarcomere, but the potential involvement of MRTFs in skeletal muscle development has not been examined. We explored the role of MRTFs in muscle development in vivo by generating mutant mice harboring a skeletal muscle-specific deletion of MRTF-B and a global deletion of MRTF-A. These double knockout (dKO) mice were able to form sarcomeres during embryogenesis. However, the sarcomeres were abnormally small and disorganized, causing skeletal muscle hypoplasia and perinatal lethality. Transcriptome analysis demonstrated dramatic dysregulation of actin genes in MRTF dKO mice, highlighting the importance of MRTFs in actin cycling and myofibrillogenesis. MRTFs were also necessary for the survival of skeletal myoblasts and for the efficient formation of intact myotubes. Our findings reveal a central role for MRTFs in sarcomere formation during skeletal muscle development and point to the potential involvement of these transcriptional coactivators in skeletal myopathies. Overall design: Gene expression profile was generated comparing wild type (WT) and HSA-Cre, MRTF-A/B double knockout mice, by deep seqencing, with three biological replicates, using Illumina HiSeq 2500.
Myocardin-related transcription factors are required for skeletal muscle development.
Specimen part, Subject
View SamplesMyocardin-Related Transcription Factors A and B (MRTF-A and MRTF-B) are highly homologous proteins that function as powerful coactivators of serum response factor (SRF), a ubiquitously expressed transcription factor essential for cardiac development. The SRF/MRTF complex binds to CArG boxes found in the control regions of genes that regulate cytoskeletal dynamics and muscle contraction, among other processes. While SRF is required for heart development and function, the role of MRTFs in the developing or adult heart has not been explored. Through cardiac-specific deletion of MRTF alleles in mice, we show that either MRTF-A or MRTF-B is dispensable for cardiac development and function, whereas deletion of both MRTF-A and MRTF-B causes a spectrum of structural and functional cardiac abnormalities. Defects observed in MRTF-A/B null mice ranged from reduced cardiac contractility and adult onset heart failure to neonatal lethality accompanied by sarcomere disarray. RNA-seq analysis on neonatal hearts identified the most altered pathways in MRTF double knockout hearts as being involved in cytoskeletal organization. Together, these findings demonstrate redundant but essential roles of the MRTFs in maintenance of cardiac structure and function and as indispensible links in cardiac cytoskeletal gene regulatory networks. Overall design: P0 Heart mRNA profiles of wild-type (WT) and MRTFA/B double knockout animals were generated in duplicate using DeepSeq using Illumina HiSeq 2500
Myocardin-related transcription factors are required for cardiac development and function.
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View SamplesPurpose: We performed RNA-Immunoprecipitation in Tandem (RIPiT) experiments against human Staufen1 (Stau1) to identify its precise RNA binding sites in a transcriptome-wide manner. To monitor the consequences of Stau1 binding in terms of target mRNA levels and ribosome occupancy, we modified the levels of endogenous Stau1 in cells by siRNA or overexpression and performed RNA-sequencing and ribosome-footprinting experiments. Staufen1 (Stau1) is a double-stranded RNA (dsRNA) binding protein implicated in mRNA transport, regulation of translation, mRNA decay and stress granule homeostasis. Here we combined RNA-Immunoprecipitation in Tandem (RIPiT) with RNase footprinting, formaldehyde crosslinking, sonication-mediated RNA fragmentation and deep sequencing to map Staufen1 binding sites transcriptome-wide. We find that Stau1 binds complex secondary structures containing multiple short helices, many of which are formed by inverted Alu elements in annotated 3''UTRs or in "strongly distal" 3''UTRs extending far beyond the canonical polyadenylation signal. Stau1 also interacts with both actively translating ribosomes and with mRNA coding sequences (CDS) and 3''UTRs in proportion to their GC-content and internal secondary structure-forming propensity. On mRNAs with high CDS GC-content, higher Stau1 levels lead to greater ribosome densities, suggesting a general role for Stau1 in modulating the ability of ribosomes to elongate through secondary structures located in CDS regions. Overall design: We used HEK293 cells expressing near endogenous levels of wild-type Flag-Stau1 (65KDa isoform with an N-Terminal Flag tag). As a control we used a mutant version of Stau1 that is not functional for dsRNA binding. Formaldehyde crosslinking experiments and RNase footprinting experiments were done in two biological replicates. All RNASeq, Ribosome footprinting and PAS-Seq were done in two biological replicates.
Staufen1 senses overall transcript secondary structure to regulate translation.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification and Functional Validation of Reciprocal microRNA-mRNA Pairings in African American Prostate Cancer Disparities.
Specimen part
View SamplesProstate cancer (PCa) tends to be more aggressive and lethal in African Americans (AA) compared to European Americans (EA). To further understand the biological factors accounting for the PCa disparities observed in AA and EA patients, we performed gene profiling using Affymetrix human exon 1.0 ST arrays to identify the differentially expressed genes beween AA cancer and patient matched normal tissues.
Identification and Functional Validation of Reciprocal microRNA-mRNA Pairings in African American Prostate Cancer Disparities.
Specimen part
View SamplesProstate cancer (PCa) tends to be more aggressive and lethal in African Americans (AA) compared to European Americans (EA). To further understand the biological factors accounting for the PCa disparities observed in AA and EA patients, we performed gene profiling analysis using Affymetrix human exon 1.0 ST arrays to identify the differentially expressed genes in AA and EA patients.
Identification and Functional Validation of Reciprocal microRNA-mRNA Pairings in African American Prostate Cancer Disparities.
Specimen part
View SamplesProstate cancer (PCa) tends to be more aggressive and lethal in African Americans (AA) compared to European Americans (EA). To further understand the biological factors accounting for the PCa disparities observed in AA and EA patients, we performed gene profiling analysis using Affymetrix human exon 1.0 ST arrays to identify the differentially expressed genes in EA PCa vs. EA normal.
Identification and Functional Validation of Reciprocal microRNA-mRNA Pairings in African American Prostate Cancer Disparities.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of key regions and genes important in the pathogenesis of sezary syndrome by combining genomic and expression microarrays.
Specimen part, Disease
View SamplesThis study used tumour and paired normal samples from 28 Szary Syndrome (SS) patients to define recurrent regions of chromosomal aberrations. Our data identified recurrent losses of 17p13.2-p11.2 and 10p12.1-q26.3 occurring in 71 and 68% of cases respectively; common gains were detected for 17p11.2-q25.3 (64%) and chromosome 8/8q (50%). Moreover, we identified novel genomic lesions recurring in more than 30% of tumours: loss of 9q13-q21.33 and gain of 10p15.3-10p12.2. In the Szary Syndrome cases analysed, we could find several small and few large Uniparental Disomies involving interstitial or telomeric regions of LOH occurring mainly for chromosome 10 and to a lesser extent for chromosome 9 and 17. In the attempt to correlate Copy Number data and clinical parameters we find a relationship between complex pattern of chromosomal aberrations, involving at least three recurrent Copy Number alterations, and shorter survival. Integrating mapping and transcriptional data we were able to identify a total of 113 deregulated transcripts in aberrant chromosomal regions that included cancer related genes such as members of the NF-kB pathway (BAG4, BTRC, NKIRAS2, PSMD3, TRAF2) that might explain its constitutive activation in CTCL. Matching this list of genes with those discriminating patients with different survival times we identify several common candidates that might exert critical roles in Szary Syndrome, like BUB3 and PIP5K1B.
Identification of key regions and genes important in the pathogenesis of sezary syndrome by combining genomic and expression microarrays.
Specimen part, Disease
View SamplesThe integration of positive and negative intra- and extra-cellular signals dictates whether a cell will proliferate or differentiate. While it is intuitive to speculate that nutrients availability may influence this alternative, a comprehensive complement of the molecular determinants involved in this process has not been elucidated yet. In this study, we will investigate how nutrients (glucose) affect skeletal myogenesis. C2C12 cells will be cultured in high glucose and low glucose conditions, and their differenciation will be studied.
Glucose restriction inhibits skeletal myoblast differentiation by activating SIRT1 through AMPK-mediated regulation of Nampt.
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