LIN28A modulates splicing and gene expression programs in breast cancer cells [RNA-Seq]
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ABSTRACT: The goals of this study were to identify LIN28 downstream gene targets in breast cancer cells. We use a subclone of the MCF-7 breast cancer cell line, MCF-7M as our model system. Methods: mRNA profiles from MCF-7M breast cancer cells treated with siRNA against non-targeting control (NT), LIN28, hnRNP A1, LIN28 and hnRNPA1 (LIN28A1) for 72 hrs were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped over 200 million sequence reads per sample to the human genome (build h19). Each of the four groups had two biological replicates. We developed a custom method to identify alternative splicing events and identified 111 genes with significant (FDR<0.05) differential splicing for LIN28 depleted cells compared to non-targeting siRNA control, as well as 249 and 182 genes for hnRNP A1 and LIN28A1 respectively. RNA-seq data were validated with by qRT–PCR analysis of a subset of genes. Conclusions: Results reveal that LIN28 regulates alternative splicing and steady state mRNA expression of genes implicated in aspects of breast cancer biology. Notably, cells lacking LIN28 undergo significant isoform switching of the ENAH gene, resulting in a decrease in the expression of ENAH exon 11a isoform. Expression of ENAH isoform 11a has been shown to be elevated in breast cancers that express HER2. mRNA profiles of MCF-7M cells treated with siRNA for NT control, LIN28, hnRNP A1, and LIN28 plus hnRNP A1 (A1) (LIN28A1) were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000
Project description:The goals of this study were to identify LIN28 downstream gene targets in breast cancer cells. We use a subclone of the MCF-7 breast cancer cell line, MCF-7M as our model system. Methods: mRNA profiles from MCF-7M breast cancer cells treated with siRNA against non-targeting control (NT), LIN28, hnRNP A1, LIN28 and hnRNPA1 (LIN28A1) for 72 hrs were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped over 200 million sequence reads per sample to the human genome (build h19). Each of the four groups had two biological replicates. We developed a custom method to identify alternative splicing events and identified 111 genes with significant (FDR<0.05) differential splicing for LIN28 depleted cells compared to non-targeting siRNA control, as well as 249 and 182 genes for hnRNP A1 and LIN28A1 respectively. RNA-seq data were validated with by qRT–PCR analysis of a subset of genes. Conclusions: Results reveal that LIN28 regulates alternative splicing and steady state mRNA expression of genes implicated in aspects of breast cancer biology. Notably, cells lacking LIN28 undergo significant isoform switching of the ENAH gene, resulting in a decrease in the expression of ENAH exon 11a isoform. Expression of ENAH isoform 11a has been shown to be elevated in breast cancers that express HER2.
Project description:The goals of this study were to identify LIN28 downstream gene targets in breast cancer cells. We use a subclone of the MCF-7 breast cancer cell line, MCF-7M as our model system. Methods: mRNA-protein complexes (mRNP) lysates were prepared from MCF-7M cells and incubated with Protein-A Sepharose beads (Sigma-Aldrich) and either LIN28 (Abcam) or control normal rabbit serum IgG antibodies. LIN28 interacting mRNAs were identified by whole genome sequencing. Results: Using an optimized data analysis workflow, we mapped approximately 13 million sequence reads for LIN28-IP and CTL- IP (IgG), respectively to the to the human genome (build h19). Conclusions: mRNA were significantly bound by LIN28 if LIN28 RIP had 2.5 fold increase in normalized reads compared to IgG. We found that LIN28 was predominantly bound at coding exons and 3'UTRs, 38% & 45% respectively, in the 843 mRNAs within MCF-7M genome.
Project description:Transcriptome analysis of total RNA samples from heart tissue of knockout mice Alternative splicing is the main mechanism to increase protein diversity from an mRNA. Heterogeneous ribonucleoprotein (hnRNP) family members are vital regulators of alternative splicing. The hnRNP A1 is the most well-known protein in this family, but its role in embryonic development is not well understood. We generated hnRNP A1 knockout mice to study the function of hnRNP A1 in vivo. The hnRNP A1-depleted mice showed embryonic lethality because of muscle developmental defects. In a previous study, cellular hnRNP A2/B1 was reported to be capable of compensating for the expression of hnRNP A1. However, this phenomenon did not occur in the hnRNP A1 heterozygous mice in vivo. We demonstrated that hnRNP A1 regulated muscle-related genes expression and alternative splicing. In summary, our data demonstrated that hnRNP A1 plays a critical role in embryonic muscle development. Understanding the effects of hnRNP A1 in vivo may help to define the function of hnRNP A1 in alternative splicing.
Project description:Heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) is a highly abundant RNA binding protein alternatively spliced in two main isoforms named, hnRNP A1 and hnRNP A1B. While being ubiquitously expressed, both isoforms have different cellular localizations and are differentially expressed in tissues during development and aging. To improve our understanding of the cellular function of each isoform, we performed RNA sequencing in cells exclusively expressing hnRNP A1 or hnRNP A1B. As expected, some genes were commonly regulated, however >300 genes were differentially regulated by the two isoforms. Functional annotation indicated an enrichment for genes implicate in cellular defense, especially for innate immunity and dsRNA response. Here, we demonstrate that in basal conditions, hnRNP A1, but not hnRNP A1B, represses interferon stimulated genes including the family of dsRNA sensors oligoadenylate synthases (OASs). Thus, the dsRNA-mediated interferon antiviral response can be potentiated by the loss of hnRNP A1-mediated repression.
Project description:Understanding how RNA binding proteins control the splicing code is fundamental to human biology and disease. Here we present a comprehensive study to elucidate how heterogeneous nuclear ribonucleoparticle (hnRNP) proteins, among the most abundant RNA binding proteins, coordinate to regulate alternative pre-mRNA splicing (AS) in human cells. Using splicing-sensitive microarrays, cross-linking and immunoprecipitation coupled with high-throughput sequencing, and cDNA sequencing, we find that more than half of all AS events are regulated by multiple hnRNP proteins, and that some combinations of hnRNP proteins exhibit significant synergy, whereas others act antagonistically. Our analyses reveal position-dependent RNA splicing maps, in vivo consensus binding sites, a surprising level of cross- and auto-regulation among hnRNP proteins, and the coordinated regulation by hnRNP proteins of dozens of other RNA binding proteins and genes associated with cancer. Our findings define an unprecedented degree of complexity and compensatory relationships among hnRNP proteins and their splicing targets that likely confer robustness to cells. RNAseq for control, hnRNP A1, hnRNP A2/B1, hnRNP H1, hnRNP F, hnRNP M, and hnRNP U siRNA treated human 293T cells
Project description:We performed EGF treatment and hnRNP A1 knockdown in HeLa cells and analyzed alternative splicing patterns by high-throughput RNA sequencing.
Project description:Understanding how RNA binding proteins control the splicing code is fundamental to human biology and disease. Here we present a comprehensive study to elucidate how heterogeneous nuclear ribonucleoparticle (hnRNP) proteins, among the most abundant RNA binding proteins, coordinate to regulate alternative pre-mRNA splicing (AS) in human cells. Using splicing-sensitive microarrays, cross-linking and immunoprecipitation coupled with high-throughput sequencing, and cDNA sequencing, we find that more than half of all AS events are regulated by multiple hnRNP proteins, and that some combinations of hnRNP proteins exhibit significant synergy, whereas others act antagonistically. Our analyses reveal position-dependent RNA splicing maps, in vivo consensus binding sites, a surprising level of cross- and auto-regulation among hnRNP proteins, and the coordinated regulation by hnRNP proteins of dozens of other RNA binding proteins and genes associated with cancer. Our findings define an unprecedented degree of complexity and compensatory relationships among hnRNP proteins and their splicing targets that likely confer robustness to cells. CLIPseq for hnRNP A1, hnRNP A2/B1, hnRNP F, hnRNP M, and hnRNP U in human 293T cells
Project description:We sought to identify alterations in RNA expression and splicing in human grey matter from the brains of people with Multiple Sclerosis (MS) where we observe mislocalization of the RNA binding protein hnRNP A1. Thus, RNA was extracted from fresh-frozen post-mortem brain samples of three people with MS and compared to RNA extracted from fresh-frozen post-mortem brain samples of three healthy controls by RNAseq. Regions of interest in human grey matter were defined by immunostaining for hnRNP A1 to confirm grey matter regions with hnRNP A1 mislocalization in MS tissue, and grey matter regions with normal hnRNP A1 localization in control tissue, and the same region from an adjacent tissue section was dissected with a razor blade and used for RNA extraction and sequencing.
Project description:Understanding how RNA binding proteins control the splicing code is fundamental to human biology and disease. Here we present a comprehensive study to elucidate how heterogeneous nuclear ribonucleoparticle (hnRNP) proteins, among the most abundant RNA binding proteins, coordinate to regulate alternative pre-mRNA splicing (AS) in human cells. Using splicing-sensitive microarrays, cross-linking and immunoprecipitation coupled with high-throughput sequencing, and cDNA sequencing, we find that more than half of all AS events are regulated by multiple hnRNP proteins, and that some combinations of hnRNP proteins exhibit significant synergy, whereas others act antagonistically. Our analyses reveal position-dependent RNA splicing maps, in vivo consensus binding sites, a surprising level of cross- and auto-regulation among hnRNP proteins, and the coordinated regulation by hnRNP proteins of dozens of other RNA binding proteins and genes associated with cancer. Our findings define an unprecedented degree of complexity and compensatory relationships among hnRNP proteins and their splicing targets that likely confer robustness to cells. In triplicate, polyA-selected RNA was extracted from control, hnRNP A1, hnRNP A2/B1, hnRNP H1, hnRNP F, hnRNP M, and hnRNP U siRNA treated human 293T cells, and hybridized to custom splice-junction arrays
Project description:Bladder cancer (BCa) is one of the most common malignant tumors of urinary system and has high incidence rate and mortality but there is a lack of effective treatment. Therefore, an in-depth study of the molecular mechanisms involved in BCa is of great significance for improving the survival of patients with advanced BCa. We found that the expression of RBMX was significantly declined in BCa, especially in muscle-invasive BCa. BCa patients with low levels of RBMX had poor prognoses. By in vitro and in vivo experiments, RBMX was shown to inhibit BCa cells growth and metastasis. Co-IP coupled with MS and GO analysis identified hnRNP A1 as a RBMX-binding protein. Mechanistically, RBMX competitively bond to the RGG box of hnRNP A1 and antagonized the hnRNP A1-mediated regulation of PKM splicing by blocking the binding of the RGG motif of hnRNP A1 to the sequences flanking PKM exon 9, resulting in downregulation of PKM2 and upregulation of PKM1. By decreasing the PKM2/PKM1 ratio, RBMX suppressed BCa cells aerobic glycolysis, which further inhibited tumorigenicity and progression of BCa.