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MtHAP2-1 is a key transcriptional regulator of symbiotic nodule development regulated by microRNA169 in Medicago truncatula.

In the model legume Medicago truncatula, we identified a new transcription factor of the CCAAT-binding family, MtHAP2-1, for which RNA interference (RNAi) and in situ hybridization experiments indicate a key role during nodule development, possibly by controlling nodule meristem function. We could also show that MtHAP2-1 is regulated by microRNA169, whose overexpression leads to the same nodule developmental block as MtHAP2-1 RNAi constructs. The complementary expression pattern of miR169 and MtHAP2-1 and the phenotype of miR169-resistant MtHAP2-1 nodules strongly suggest, in addition, that the miR169-mediated restriction of MtHAP2-1 expression to the nodule meristematic zone is essential for the differentiation of nodule cells.

Base Sequence↗

Transcriptome analysis for the chicken based on 19,626 finished cDNA sequences and 485,337 expressed sequence tags.

We present an analysis of the chicken (Gallus gallus) transcriptome based on the full insert sequences for 19,626 cDNAs, combined with 485,337 EST sequences. The cDNA data set has been functionally annotated and describes a minimum of 11,929 chicken coding genes, including the sequence for 2260 full-length cDNAs together with a collection of noncoding (nc) cDNAs that have been stringently filtered to remove untranslated regions of coding mRNAs. The combined collection of cDNAs and ESTs describe 62,546 clustered transcripts and provide transcriptional evidence for a total of 18,989 chicken genes, including 88% of the annotated Ensembl gene set. Analysis of the ncRNAs reveals a set that is highly conserved in chickens and mammals, including sequences for 14 pri-miRNAs encoding 23 different miRNAs. The data sets described here provide a transcriptome toolkit linked to physical clones for bioinformaticians and experimental biologists who wish to use chicken systems as a low-cost, accessible alternative to mammals for the analysis of vertebrate development, immunology, and cell biology.

Animals↗

Beyond parental lines: multi-omics analyses reveal epigenetic and transcriptional mechanisms underlying heterosis in Oryza sativa × Oryza rufipogon hybrids.

Heterosis, or hybrid vigor, refers to the superior phenotypes of a hybrid compared with their parents and is widely exploited in agriculture. Interspecific hybrids within the Oryza genus demonstrate significant potential for the systematic improvement of rice varieties. Nevertheless, the mechanistic basis underlying heterosis in interspecific Oryza hybrids remains poorly understood. Here, we systematically performed phenotypic characterization, whole-genome bisulfite sequencing, RNA sequencing, and small RNA profiling using Oryza sativa L. ssp. japonica cv. Nipponbare (NIP), Oryza rufipogon Griff. acc. CWR, and their resulting F1 hybrid (named as NC). NIP and CWR showed distinct phenotypic and molecular differences. The interspecific hybrid, NC, exhibited significant yield heterosis. In the hybrid, most epigenetic and transcriptional features displayed additive inheritance patterns relative to parental lines. Analysis revealed that domestication-selected genes maintained relatively low DNA methylation coupled with high expression levels in both hybrid and parental lines. Additionally, we identified that non-additive miRNAs were potentially involved in regulating fertility, cell growth, and cell division processes in the hybrid. A significant negative correlation was observed between DNA methylation level and gene expression. Functional enrichment analysis revealed that hybrid-MPV DEGs were significantly associated with flowering time regulation, carbohydrate metabolism, photosynthesis, protein phosphorylation, seed development, and defense responses. Through weighted gene co-expression network analysis, we identified 102 functional gene modules, six of which were significantly associated with yield-related heterosis. Collectively, our results provide a multi-omics framework for understanding interspecific hybridization between elite cultivars and wild rice relatives, highlighting CWR as an untapped genetic reservoir for rice improvement.

Oryza↗

Role for amplification and expression of glypican-5 in rhabdomyosarcoma.

Overexpression of genes, through genomic amplification and other mechanisms, can critically affect the behavior of tumor cells. Genomic amplification of the 13q31-32 region is reported in many tumors, including rhabdomyosarcomas that are primarily pediatric sarcomas resembling developing skeletal muscle. The minimum overlapping region of amplification at 13q31-32 in rhabdomyosarcomas was defined as containing two genes: Glypican-5 (GPC5) encoding a cell surface proteoglycan and C13orf25 encompassing the miR-17-92 micro-RNA cluster. Genomic copy number and gene expression analyses of rhabdomyosarcomas indicated that GPC5 was the only gene consistently expressed and up-regulated in all cases with amplification. Constitutive overexpression and knockdown of GPC5 expression in rhabdomyosarcoma cell lines increased and decreased cell proliferation, respectively. A correlation between expression levels of nascent pre-rRNA and GPC5 (P = 0.001), but not a C13orf25 transcript containing miR-17-92, in primary samples supports an association of GPC5 with proliferative capacity in vivo. We show that GPC5 increases proliferation through potentiating the action of the growth factors fibroblast growth factor 2 (FGF2), hepatocyte growth factor (HGF), and Wnt1A. GPC5 enhanced the intracellular signaling of FGF2 and HGF and altered the cellular distribution of FGF2. The mesoderm-inducing effect of FGF2 and FGF4 in Xenopus blastocysts was also enhanced. Our data are consistent with a role of GPC5, in the context of sarcomagenesis, in enhancing FGF signaling that leads to mesodermal cell proliferation without induction of myogenic differentiation. Furthermore, the properties of GPC5 make it an attractive target for therapeutic intervention in rhabdomyosarcomas and other tumors that amplify and/or overexpress the gene.

Amino Acid Sequence↗

PI3K signaling and miRNA expression during the response of quiescent human fibroblasts to distinct proliferative stimuli.

BACKGROUND: Serum treatment of quiescent human dermal fibroblasts induces proliferation, coupled with a complex physiological response that is indicative of their normal role in wound-healing. However, it is not known to what extent such complex transcriptional events are specific to a given cell type and signal, and how these global changes are coordinately regulated. We have profiled the global transcriptional program of human fibroblasts from two different tissue sources to distinct growth stimuli, and identified a striking conservation in their gene-expression signatures. RESULTS: We found that the wound-healing program of gene expression was not specific to the response of dermal fibroblasts to serum but was regulated more broadly. However, there were specific differences among different stimuli with regard to signaling pathways that mediate these transcriptional programs. Our data suggest that the PI3-kinase pathway is differentially involved in mediating the responses of cells to serum as compared with individual peptide growth factors. Expression profiling indicated that let7 and other miRNAs with similar expression profiles may be involved in regulating the transcriptional program in response to proliferative signals. CONCLUSION: This study provides insights into how different stimuli use distinct as well as conserved signaling and regulatory mechanisms to mediate genome-wide transcriptional reprogramming during cell proliferation. Our results indicate that conservation of transcriptional programs and their regulation among different cell types may be much broader than previously appreciated.

Cell Line↗

Identification and analysis of key genes related to efferocytosis in colorectal cancer.

UNLABELLED: The impact of efferocytosis-related genes (ERGs) on the diagnosis of colorectal cancer (CRC) remains unclear. In this study, efferocytosis-associated biomarkers for the diagnosis of CRC were identified by integrating data from transcriptome sequencing and public databases. Finally, the expression of biomarkers was validated by real-time quantitative polymerase chain reaction (RT-qPCR). Our study may provide a reference for CRC diagnosis. BACKGROUND: It has been shown that some efferocytosis related genes (ERGs) are associated with the development of cancer. However, it is still uncertain how ERGs may influence the diagnosis of colorectal cancer (CRC). METHODS: In our study, the CRC cohorts were gained from transcriptome sequencing and the gene expression omnibus (GEO) database (GSE71187). Efferocytosis related biomarkers with diagnostic utility for CRC were identified through combining differentially expressed analysis, machine learning algorithms, and receiver operating characteristic (ROC) analysis. Then, infiltration abundance of immune cells between CRC and control was evaluated. The regulatory networks (including mRNA-miRNA-lncRNA and miRNA/transcription factors (TF)-mRNA networks) were created. Finally, the expression of biomarkers was validated via real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: There were 3 biomarkers (ELMO3, P2RY12, and PDK4) related diagnosis for CRC patients gained. ELMO3 was highly expressed in CRC group, while P2RY12 and PDK4 was lowly expressed. Besides, the infiltrating abundance of 3 immune cells between CRC and control groups was significantly differential, namely activated CD4 memory T cells, macrophages M0, and resting mast cells. We then constructed a mRNA-miRNA-lncRNA network containing 3 mRNAs, 33 miRNAs, and 22 lncRNAs, and a miRNA/TF-mRNA network including 3 mRNAs, 33 miRNAs, and 7 TFs. Additionally, RT-qPCR results revealed that the expression trends of all biomarkers were consistent with the transcriptome sequencing data and GSE71187. CONCLUSION: Taken together, this study provides three efferocytosis related biomarkers (ELMO3, P2RY12, and PDK4) for diagnosis of CRC, providing a scientific reference for further studies of CRC.

Humans↗

A regulatory network underlying idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease in which genetic susceptibility interacts with epithelial, immune, and mesenchymal remodeling. Although the chromosome 11p15.5 locus contains established IPF susceptibility signals near MUC5B and TOLLIP, the broader regulatory architecture of this region remains incompletely resolved. METHODS: We integrated IPF genome-wide association study summary statistics with methylation, expression, and protein quantitative trait loci using summary-data-based Mendelian randomization (SMR). SMR-prioritized candidates were evaluated in independent transcriptomic and methylation cohorts and further contextualized using microRNA, transcription-factor, protein-interaction, machine-learning, single-cell, and spatial transcriptomic analyses. Fibrosis-associated expression patterns were assessed in a bleomycin-induced pulmonary fibrosis rat model. RESULTS: The analyses recovered the established MUC5B and TOLLIP signals and prioritized BRSK2 as a comparatively underexplored candidate supported by eQTL-based SMR and independent molecular evidence. The BRSK2 pQTL association did not pass the HEIDI test and was therefore not interpreted as convergent protein-level genetic evidence. Network analyses linked BRSK2 to cell-cycle, metabolic-stress, and senescence-related programs, while cross-cohort machine learning prioritized FOXA2, CDC25B, and NFE2 as informative network features. Single-cell and spatial analyses localized BRSK2 preferentially to fibroblast and myofibroblast compartments and to regions with greater histological fibrosis severity. In fibrotic rat lungs, BRSK2 expression increased, whereas FOXA2 and CDC25B decreased at the transcript and protein levels. CONCLUSIONS: These findings refine the molecular landscape of the chromosome 11p15.5 IPF susceptibility locus and prioritize BRSK2 as a candidate component of an IPF-associated profibrotic fibroblast state. Its causal contribution, direct regulatory relationships, and therapeutic tractability require targeted mechanistic validation.

Idiopathic Pulmonary Fibrosis↗

Regulation of gene expression in mast cells: micro-rNA expression and chromatin structural analysis of cytokine genes.

Despite deriving from two different compartments of the immune system (myeloid and lymphoid respectively), Th2 cells and mast cells produce the same panel of cytokines, interleukin (IL)4, IL5 and IL13. We have compared the chromatin structure of the RAD50/IL13/IL4 locus in Th2 cells and mast cells. Th2 and mast cells display strong overlap in their patterns of DNase I hypersensitivity throughout this locus, except that the first intron of the IL13 gene (MCHS) is DNase I hypersensitive only in mast cells and the conserved non-coding sequence (CNS)-1 in the IL4/IL13 intergenic region is DNase I hypersensitive only in Th2 cells (explaining why cytokine expression is impaired in Th2 cells but not in mast cells of CNS-1-deleted mice). We have also examined the role of micro-RNAs (miRNAs) in the development and activation of mast cells and T cells. miRNAs are 21- to 25-nucleotide small RNAs that regulate gene expression posttranscriptionally by targeting protein-coding mRNAs. Using oligonucleotide arrays to analyse miRNA expression in murine T cells and mast cells, we have identified distinctive cell type-specific patterns of miRNA expression as well as changes related to differentiation and cell activation. We are studying the biological functions of selected miRNAs.

Animals↗

Post-transcriptional regulation of the let-7 microRNA during neural cell specification.

The let-7 miRNA regulates developmental timing in C. elegans and is an important paradigm for investigations of miRNA functions in mammalian development. We have examined the role of miRNA precursor processing in the temporal control and lineage specificity of the let-7 miRNA. In situ hybridization (ISH) in E9.5 mouse embryos revealed early induction of let-7 in the developing central nervous system. The expression pattern of three let-7 family members closely resembled that of the brain-enriched miRNAs mir-124, mir-125 and mir-128. Comparison of primary, precursor, and mature let-7 RNA levels during both embryonic brain development and neural differentiation of embryonic stem cells and embryocarcinoma (EC) cells suggest post-transcriptional regulation of let-7 accumulation. Reflecting these results, let-7 sensor constructs were strongly down-regulated during neural differentiation of EC cells and displayed lineage specificity in primary cells. Neural differentiation of EC cells was accompanied by an increase in let-7 precursor processing activity in vitro. Furthermore, undifferentiated and differentiated cells contained distinct precursor RNA binding complexes. A neuron-enhanced binding complex was shown by antibody challenge to contain the miRNA pathway proteins Argonaute1 and FMRP. Developmental regulation of the processing pathway correlates with differential localization of the proteins Argonaute, FMRP, MOV10, and TNRC6B in self-renewing stem cells and neurons.

Animals↗

siRNA and miRNA: an insight into RISCs.

Two classes of short RNA molecule, small interfering RNA (siRNA) and microRNA (miRNA), have been identified as sequence-specific posttranscriptional regulators of gene expression. siRNA and miRNA are incorporated into related RNA-induced silencing complexes (RISCs), termed siRISC and miRISC, respectively. The current model argues that siRISC and miRISC are functionally interchangeable and target specific mRNAs for cleavage or translational repression, depending on the extent of sequence complementarity between the small RNA and its target. Emerging evidence indicates, however, that siRISC and miRISC are distinct complexes that regulate mRNA stability and translation. The assembly of RISCs can be traced from the biogenesis of the small RNA molecules and the recruitment of these RNAs by the RISC loading complex (RLC) to the transition of the RLC into the active RISC. Target recognition by the RISC can then take place through different interacting modes.

Animals↗

Annexin A2 binds the 3'-UTR of H2AX mRNA and regulates histone-H2AX-derived hypoxia-inducible factor 1-alpha activation.

Annexin A2 (Anxa2), a multifunctional protein with RNA-binding capabilities, is frequently overexpressed in various tumors, and its expression is highly correlated with malignant progression. In this study, we demonstrate for the first time that Anxa2 was co-expressed with glycolytic genes, suggesting its potential role as a regulator of glycolysis. RNA-protein interaction assay revealed that Anxa2 interacted with 3'-UTR of H2AX mRNA and protected it from miRNA-mediated degradation. Up-regulated Histone-H2AX enhances the expression of glycolytic genes including GLUT1, HK2, PGK1, ENO1, PKM2, GAPDH and LDHA via stabilizing hypoxia-inducible factor 1-alpha (HIF1α), thereby accelerating lactic acid production and secretion. (20S) G-Rh2, a natural compound targeting Anxa2, significantly interfered the Anxa2-H2AX mRNA interaction, and inhibited subsequent glycolysis progression. We propose that Anxa2 acts as a novel regulator in glycolysis via enhancing H2AX expression, and (20S) G-Rh2 may exert its anti-cancer activity by targeting Anxa2-H2AX-HIF1α-glycolysis axis in human hepatoma HepG2 cells.

Humans↗

Effect of ret/PTC 1 rearrangement on transcription and post-transcriptional regulation in a papillary thyroid carcinoma model.

BACKGROUND: microRNAs (miRNAs) are a group of non-coding single stranded RNAs measuring approximately 22 nt in length that have been found to control cell growth, differentiation and apoptosis. miRNAs negatively regulate their target genes and recently have been implicated in tumourigenesis. Furthermore, miRNA expression profiling correlates with various cancers, with these genes thought to act as both tumour suppressors and oncogenes. ret/PTC 1 is an oncogene with constitutive kinase activity implicated in the development of papillary thyroid carcinoma (PTC). This rearrangement leads to aberrant MAPK activation that is implicated in PTC tumourigenesis. AIM: The aim of this study was to identify the effect that ret/PTC 1 has on transcription and post-transcriptional regulation in PTC by using DNA microarray and microRNA analysis. RESULTS: DNA microarray analysis revealed a group of genes differentially expressed between normal thyroid cell lines and those harbouring a ret/PTC 1 rearrangement.Furthermore, a unique miRNA expression signature differentiated between PTC cell lines with ret/PTC 1 and a normal thyroid cell line. 21 miRNAs showed significant overexpression and 14 miRNAs showed underexpression in these cell lines when compared to normal thyroid. Several of these up/down regulated miRNAs may be involved in PTC pathogenesis.

Biomarkers, Tumor↗

The role of microRNAs in normal hematopoiesis and hematopoietic malignancies.

Over the past few years, it has become evident that microRNAs (miRNAs) play an important regulatory role in various biological processes. Much effort has been put into the elucidation of their biogenesis, and this has led to the general concept that a number of key regulators are shared with the processing machinery of small interfering RNAs. Despite the recognition that several miRNAs play crucial roles in normal development and in diseases, little is known about their exact molecular function and the identity of their target genes. In this review, we report on the biological relevance of miRNAs for the differentiation of normal hematopoietic cells and on the contribution of deregulated miRNA expression in their malignant counterparts.

Animals↗

Incorporating prior information in gene expression network-based cancer heterogeneity analysis.

Cancer is molecularly heterogeneous, with seemingly similar patients having different molecular landscapes and accordingly different clinical behaviors. In recent studies, gene expression networks have been shown as more effective/informative for cancer heterogeneity analysis than some simpler measures. Gene interconnections can be classified as "direct" and "indirect," where the latter can be caused by shared genomic regulators (such as transcription factors, microRNAs, and other regulatory molecules) and other mechanisms. It has been suggested that incorporating the regulators of gene expressions in network analysis and focusing on the direct interconnections can lead to a deeper understanding of the more essential gene interconnections. Such analysis can be seriously challenged by the large number of parameters (jointly caused by network analysis, incorporation of regulators, and heterogeneity) and often weak signals. To effectively tackle this problem, we propose incorporating prior information contained in the published literature. A key challenge is that such prior information can be partial or even wrong. We develop a two-step procedure that can flexibly accommodate different levels of prior information quality. Simulation demonstrates the effectiveness of the proposed approach and its superiority over relevant competitors. In the analysis of a breast cancer dataset, findings different from the alternatives are made, and the identified sample subgroups have important clinical differences.

Humans↗

Imprinted microRNA genes transcribed antisense to a reciprocally imprinted retrotransposon-like gene.

MicroRNAs (miRNAs) are an abundant class of RNAs that are approximately 21-25 nucleotides (nt) long, interact with mRNAs and trigger either translation repression or RNA cleavage (RNA interference, RNAi) depending on the degree of complementarity with their targets. Here we show that the imprinted mouse distal chromosome 12 locus encodes two miRNA genes expressed from the maternally inherited chromosome and antisense to a retrotransposon-like gene (Rtl1) expressed only from the paternal allele.

Animals↗