Project description:ChIP-seq is combined with RNA-seq analysis to identify the TBX3 and HAND2 target genes during mouse limb bud development. This analysis identifies the DEGs and direct transcriptional targets of HAND2 and TBX3 during the early determinative period critical to establishment of limb axis polarity and the SHH signaling center in the posterior limb bud mesenchyme. In particular, bioinformatics analysis identifies the target gene networks that are co-regulated by both TBX3 and HAND2 transcription factors in the limb bud mesenchyme. A significant fraction of the target genes identified are required for normal limb bud development and their spatio-temporal expression patterns are changed in mutant limb buds at early stages. This project was supported by SNSF Grant 310030_184734 to Rolf Zeller (project partner: Aimée Zuniga).
Project description:ChIP-seq is combined with RNA-seq analysis to identify the TBX3 and HAND2 target genes during mouse limb bud development. This analysis identifies the DEGs and direct transcriptional targets of HAND2 and TBX3 during the early determinative period critical to establishment of limb axis polarity and the SHH signaling center in the posterior limb bud mesenchyme. In particular, bioinformatics analysis identifies the target gene networks that are co-regulated by both TBX3 and HAND2 transcription factors in the limb bud mesenchyme. A significant fraction of the target genes identified are required for normal limb bud development and their spatio-temporal expression patterns are changed in mutant limb buds at early stages. This project was supported by SNSF Grant 310030_184734 to Rolf Zeller (project partner: Aimée Zuniga).
Project description:Long non-coding RNAs (lncRNAs) are emerging as important players in the regulation of several aspects of cellular biology. For a better comprehension of their function it is fundamental to determine their expression in single cells, to identify their subcellular localization and eventually DNA interacting regions. In fact, lncRNAs present a cell-type specific expression and different functions depending on their subcellular localization. C2C12 cells are a model to study muscle pathophysiology and differentiation. We used this model to evaluate Pvt1-DNA interacting regions. We demonstrated that the lncRNA Pvt1, early activated during muscle atrophy, regulate the transcription of DNA and influence mitochondrial respiration and morphology ultimately impinging mito/autophagy and myofiber size in vivo. We evidenced that the long non-coding RNA Pvt1 is highly expressed during skeletal muscle atrophy. Moreover, it is preferentially expressed in fast contracting myofibers. By using high throughput techniques and Fluorescent In Situ Hybridization we evidenced that Pvt1 localize inside the nucleai of myofibers and C2C12 cells. C2C12 cells are widely used as in vitro model to study different aspects of muscle biology such as development, differentiation and metabolism. Because Pvt1 nuclear localization we checked its capacity to interact with DNA by Chromatin isolation by RNA purification (ChIRP).
Project description:In vitro models allow for the study of developmental processes outside of the embryo. To gain access to the cells mediating digit and joint development, we identified a unique property of undifferentiated mesenchyme isolated from the distal early autopod to autonomously re-assemble forming multiple autopod structures including: digits, interdigital tissues, joints, muscles and tendons. Single cell transcriptomic analysis of these developing structures revealed distinct cell clusters that express canonical markers of distal limb development including: Col2a1, Col10a1, and Sp7 (phalanx formation) Thbs2 and Col1a1, (perichondrium), Gdf5, Wnt5a, and Jun (joint interzone), Aldh1a2 and Msx1 (interdigital tissues), Myod1 (muscle progenitors), Prg4 (articular perichondrium/articular cartilage), and Scx and Tnmd (tenocytes/tendons). Analysis of the gene expression patterns for these signature genes indicates that developmental timing and tissue-specific localization were also recapitulated in a manner similar to the initiation and maturation of the developing murine autopod. Finally, the in vitro digit system also recapitulates congenital malformations associated with genetic mutations as in vitro cultures of Hoxa13 mutant mesenchyme produced defects present in Hoxa13 mutant autopods including digit fusions, reduced phalangeal segment numbers, and poor mesenchymal condensation. These findings demonstrate the robustness of the in vitro digit system to recapitulate digit and joint development. As an in vitro model of murine digit and joint development, this innovative system will provide access to developing limb tissues facilitating studies to discern how digit and articular joint formation is initiated and how undifferentiated mesenchyme is patterned to establish individual digit morphologies. The in vitro digit system also provides a platform to rapidly evaluate treatments aimed at stimulating the repair or regeneration of mammalian digits impacted by congenital malformation, injury, or disease.
Project description:We report that long noncoding RNAs contribute to transcription and developmental process. Thousands of lncRNAs have been identified in the whole genome, and tend to located closely to protein-coding genes. To study position relationship between lncRNA and protein-coding genes, we classified all of lncRNA to several subgroups based on the genome position with their coding neighbors. XH, the head to head subgroup is associated with transcription and development in GO analysis. Here, we knockdown serveral XH lncRNA by shRNA in embryonic stem cells and induce nondirectional differnetiation by removing LIF or neural differnetiation by RA. Knockdown of XH lncRNAs led to uniform downregulation of nearby coding genes, and form regulatory circuits with its nearby coding genes to fine-tune embryonic lineage development. In addition, we also knockout one lncRNA-Evx1as and its nearby protein-coding gene-EVX1 by CRISPR, and get similar results as knockdown.We propose that XH lncRNA may function primarily as 'cis-regulators' of the expression of nearby protein-coding genes, and tend to participate in transcriptional or development regulations as their coding neighbors. All RNA-seq(s) were designed to reveal the differentially expressed genes between wild-type and XH lncRNA knockdown/knockout ESCs during differentiation.
Project description:Distal limb mesenchyme cells were collected from embryonic chickens at Hamburger Hamilton (HH) stages HH24 and HH27, and from samples that had been grafted from HH20 to HH24 and left to develop for 24 hours. Bioinformatics and clustering analyses were then performed to determine whether grafted cells are more similar to HH24 (graft stage) or HH27 (host stage).
Project description:Salamander limb regeneration is dependent upon tissue interactions that are local to the amputation site. Communication among limb epidermis, peripheral nerves, and mesenchyme coordinate cell migration, cell proliferation, and tissue patterning to generate a blastema, a mass of progenitor cells that forms missing limb structures. An outstanding question is how molecular cross-talk between these tissues gives rise to the regeneration blastema. To identify genes associated with epidermis-nerve-mesenchymal interactions during limb regeneration, we examined histological and transcriptional changes during the first week following injury in the wound epidermis and subjacent cells between three injury types; 1) a flank wound on the side of the animal that will not regenerate a limb, 2) a denervated limb that will not regenerate a limb, and 3) an innervated limb that will regenerate a limb. Early, histological and transcriptional changes were highly similar between the three injury types, presumably because a common wound-healing program is employed across anatomical locations. However, we identified transcripts that were enriched in the limb compared to the flank and are associated with vertebrate limb development. Many of these genes were activated before blastema outgrowth and in situ hybridization showed that some of these genes were expressed in specific tissue types including the epidermis, peripheral nerve, and mesenchyme. We also identified a relatively small group of transcripts that were more highly expressed in innervated limbs versus denervated limbs. These transcripts encode for proteins that are associated with myelination of peripheral nerves, epidermal maintenance, and cell proliferation, suggesting that denervation affects myelinating Schwann cells, epidermal cell function, and proliferation of mesenchymal cells. Overall, our study identifies limb-specific and nerve-dependent genes that are upstream of regenerative growth, and thus promising candidates for the regulation of blastema formation. We used microarray analysis to determine the gene expression changes that take place during limb regeneration, flank wound healing, and an denervated amputated limb. Epidermal tissue and cells adhered to the epidermis were collected as samples. Two harvested samples was pooled for each animal. Four biological replicates were collected from uninjured epidermis (D0) and at 1, 3, and 7 days post injury.