Differentially expressed genes during axolotl jaw regeneration identified by RNA-seq
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ABSTRACT:
ORGANISM(S): Ambystoma mexicanum
PROVIDER: GSE95355 | GEO | 2018/12/01
REPOSITORIES: GEO
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Project description:An outstanding mystery in biology is why some species, such as the axolotl, can regenerate tissues whereas mammals cannot1. Here, we demonstrate that rapid activation of protein synthesis is a unique feature of the injury response critical for limb regeneration in the axolotl (Ambystoma mexicanum). By applying polysome sequencing, we identify hundreds of transcripts, including antioxidants and ribosome components that are selectively activated at the level of translation from pre-existing messenger RNAs in response to injury. By contrast, protein synthesis is not activated in response to non-regenerative digit amputation in the mouse. We identify the mTORC1 pathway as a key upstream signal that mediates tissue regeneration and translational control in the axolotl. We discover unique expansions in mTOR protein sequence among urodele amphibians. By engineering an axolotl mTOR (axmTOR) in human cells, we show that these changes create a hypersensitive kinase that allows axolotls to maintain this pathway in a highly labile state primed for rapid activation. This change renders axolotl mTOR more sensitive to nutrient sensing, and inhibition of amino acid transport is sufficient to inhibit tissue regeneration. Together, these findings highlight the unanticipated impact of the translatome on orchestrating the early steps of wound healing in a highly regenerative species and provide a missing link in our understanding of vertebrate regenerative potential.
2023-05-08 | GSE185593 | GEO
Project description:The Mexican axolotl (Ambystoma mexicanum) is one member of a select group of vertebrate animals that has retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl is also a leading model system for developmental biologists. Many genes used in development have been identified to be reused again during regeneration, however how this molecular circuitry is controlled during regeneration is unknown. In recent years microRNAs have been identified as key regulators of gene expression during development, in many diseases and also in regeneration. Here we have used deep sequencing combined with qRT-PCR to identify microRNAs that are involved in regulating regeneration in axolotl. This approach has enabled us to identify well known families of microRNAs and in addition to identify putative novel microRNAs that differentially regulated in the regenerating tissue. These findings suggest that microRNAs may play key roles in managing the spatial and temporal expression of genes important for ensuring that the correct tissues are regenerated. small RNA Sequencing (2 samples) in Ambystoma Mexicanum
2015-09-11 | E-GEOD-72057 | biostudies-arrayexpress
Project description:The jaws are complementary in form and function but develop asymmetrically, as the lower but not upper jaw bone forms around a prominent cartilage template. How such differences in skeletal composition are patterned is unclear. Here, we identify four Nuclear receptor 2f genes, nr2f1a, nr2f1b, nr2f2, and nr2f5, as enriched in zebrafish upper jaw precursors. Whereas loss of Nr2f genes results in expansion of upper jaw cartilage to resemble that of the lower jaw, Nr2f5 misexpression inhibits lower jaw cartilage formation. Genome-wide analyses show that Nr2f genes prevent expansion of lower jaw-associated gene expression into the upper jaw territory. Further, restriction of Nr2f expression by Endothelin1 signaling is critical for lower jaw development, as reducing Nr2f dosage fully restores lower jaw development in edn1 mutants. We propose that Nr2f genes drive jaw asymmetry by limiting early cartilage differentiation in the upper jaw to preserve more precursors for later osteogenesis.
2018-01-18 | GSE101719 | GEO
Project description:Despite even large phenotypic differences among vertebrate groups, dentitions and jaws fit and function together, yet the genetic processes that orchestrate cranial and dental morphogenesis remain poorly understood. In the p63-/- mouse mutant, teeth but not jaws fail to form. This edentate mouse is a model with which to tease out genes important for odontogenesis but not jaw morphogenesis, and which may thus allow dentitions to change during development and evolution without necessarily affecting the jaw skeleton. With the working hypothesis that tooth and jaw development are autonomously controlled by discreet gene regulatory networks, we probed for genes crucial for tooth development only. Using gene expression microarray assays validated by quantitative reverse-transcription PCR, we contrasted expression in mandibular prominences at embryonic days (E) 10-13 among mice with normal lower jaw development and either normal (p63+/-, p63+/+) or arrested (p63-/-) tooth development. We predicted that expression of a suite of genes specific to odontogenesis would differ in the edentate mice. The p63-/- mice showed significantly different expression (fold change ≥1.5, ≤-1.5; p≤0.05) of several genes, some of which are already reported to help regulate odontogenesis (e.g., p63, Osr2, Cldn3/4) and/or to be targets of p63 (e.g., Jag1/2, Fgfr2), others of which have no previously reported roles in odontogenesis or the p63 pathway (e.g, Fermt1, Cbln1, Pltp, Cxcl14, Krt8, and additional keratin and claudin family members). As expected, from E10-E13 few genes known to regulate mandible morphogenesis differed in expression between mouse strains. Thus this study links for the first time several genes to odontogenesis and/or the p63 signaling network. We propose that these genes act in a novel odontogenic network that is exclusive of lower jaw morphogenesis, and posit that this network evolved in oral, not pharyngeal, teeth.
2016-12-23 | GSE92769 | GEO
Project description:Salamanders have the remarkable ability to functionally regenerate after spinal cord transection. In response to injury, GFAP+ glial cells in the axolotl spinal cord proliferate and migrate to replace the missing neural tube and create a permissive environment for axon regeneration. Molecular pathways that regulate the pro-regenerative axolotl glial cell response are poorly understood. Here we show axolotl glial cells up-regulate AP-1cFos/JunB after injury, which promotes a pro-regenerative glial cell response. Axolotl glial cells directly repress c-Jun expression via up-regulation of miR-200a. Inhibition of miR-200a during regeneration causes defects in axonal regrowth and transcriptomic analysis revealed that miR-200a inhibition leads to differential regulation of genes involved with reactive gliosis, the glial scar, ECM remodeling and axon guidance. This work identifies a novel role for miR-200a in inhibiting reactive gliosis in glial cell in axolotl during spinal cord regeneration
2019-03-19 | GSE122939 | GEO
Project description:Study abstract: Axolotl salamanders (Ambystoma mexicanum) remain aquatic in their natural state, during which biomechanical forces on their diarthrodial limb joints are likely reduced relative to salamanders living on land. However, even as sexually mature adults, these amphibians can be induced to metamorphose into a weight-bearing terrestrial stage by environmental stress or the exogenous administration of thyroxine hormone. In some respects, this aquatic to terrestrial transition of axolotl salamanders through metamorphosis may model developmental and changing biomechanical skeletal forces in mammals during the prenatal to postnatal transition at birth and in the early postnatal period. To assess differences in the appendicular skeleton as a function of metamorphosis, anatomical and gene expression parameters were compared in skeletal tissues between aquatic and terrestrial axolotls that were the same age and genetically full siblings. The length of long bones and area of cuboidal bones in the appendicular skeleton, as well as the cellularity of cartilaginous and interzone tissues of femorotibial joints were generally higher in aquatic axolotls compared to their metamorphosed terrestrial siblings. A comparison of steady state mRNA transcripts encoding aggrecan core protein (ACAN), type II collagen (COL2A1), and growth and differentiation factor 5 (GDF5) in femorotibial cartilaginous and interzone tissues did not reveal any significant differences between aquatic and terrestrial axolotls. RNAseq samples: Total RNA was isolated from whole body tissue samples of Mexican axolotl salamanders (Ambystoma mexicanum) at the following developmental stages: Embryo at the tail bud stage, newly hatched larva, larva at the limb bud stage, juvenile at 8.5 centimeters, and adult using variations of guanidinium-based protocols. RNA quantity, purity, and integrity of both the individual samples and the resulting pool were determined with an Agilent 2100 Bioanalyzer using the Eukaryotic Total RNA nano series II analysis kit. The pooled RNA sample was poly-A selected and used for Illumina random priming directional library prep. Four lanes were sequenced only on one end providing single end reads and 4 lanes were sequenced at both ends giving paired-end reads. The library was sequenced on an Illumina HiSeq 2000 for 75bp reads producing 147,248,512 single end reads and 2 x 153,254,667 paired-end reads.
2018-07-29 | E-MTAB-6092 | biostudies-arrayexpress
Project description:The asymmetric localization of maternal biomolecules is critical for body plan development. One of the most popular model organisms for early embryogenesis studies is Xenopus laevis but there is a lack of information in other animal species. Here, we compare the early development of two amphibian species – the frog X. laevis and the axolotl Ambystoma mexicanum. This study aimed to identify asymmetrically localized RNAs along the animal-vegetal axis during the early development of A. mexicanum. For that purpose, we performed spatial transcriptome-wide analysis, which revealed dynamic changes along the animal-vegetal axis classified into the following categories: relocalization, de novo synthesis and degradation. Surprisingly, our results showed that many of the vegetally localized genes, which are important for germ cell development, are degraded during early development. Furthermore, we assessed the motif presence in UTRs of degraded mRNAs and revealed the enrichment of several motifs in RNAs of germ cell markers. Our results suggest novel reorganization of the transcriptome during embryogenesis of A. mexicanum to converge to the similar developmental pattern as the X. laevis.
2023-11-21 | GSE240796 | GEO
Project description:The Mexican axolotl (Ambystoma mexicanum) is one member of a select group of vertebrate animals that has retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl is also a leading model system for developmental biologists. Many genes used in development have been identified to be reused again during regeneration, however how this molecular circuitry is controlled during regeneration is unknown. In recent years microRNAs have been identified as key regulators of gene expression during development, in many diseases and also in regeneration. Here we have used deep sequencing combined with qRT-PCR to identify microRNAs that are involved in regulating regeneration in axolotl. This approach has enabled us to identify well known families of microRNAs and in addition to identify putative novel microRNAs that differentially regulated in the regenerating tissue. These findings suggest that microRNAs may play key roles in managing the spatial and temporal expression of genes important for ensuring that the correct tissues are regenerated.
2015-09-11 | GSE72057 | GEO
Project description:Transcriptome studies are revealing the complex gene expression basis of limb regeneration in the primary salamander model – Ambystoma mexicanum (axolotl). To better understand this complexity, there is need to extend analyses to additional salamander species. Using microarray and RNA-Seq, we performed a comparative transcriptomic study using A. mexicanum and two other ambystomatid salamanders: A. andersoni, and A. maculatum. Salamanders were administered forelimb amputations and RNA was isolated and analyzed to identify 405 non-redundant genes that were commonly, differentially expressed 24 hours post amputation. Many of the upregulated genes are predicted to function in wound healing and developmental processes, while many of the downregulated genes are typically expressed in muscle. The conserved transcriptional changes identified in this study provide a high-confidence dataset for identifying factors that simultaneous orchestrate wound healing and regeneration processes in response to injury, and more generally for identifying genes that are essential for salamander limb regeneration.
2018-07-10 | GSE116777 | GEO