Project description:Analysis of gene expression in the distal forelimbs RNA-Seq polyA on transcripts extracted from the dissection of three pairs of embryonnic forelimbs at E12.5
Project description:The bat offers an alternative paradigm to the standard mouse and chick model of limb development as it has extremely divergent forelimbs (long digits supporting a wing) and hindlimbs (short digits and claws) due the distinct requirements of both aerial and terrestrial locomotion. We used a cross-species microarray approach to identify differentially expressed (DE) genes between the bat (Minniopterus natalensis) forelimb and hindlimb autopods at Carollia developmental stages (CS) 16 and CS17, and between the bat (CS17) and mouse (E13.5) forelimb autopods. Several DE genes were identified, including two homeobox genes, Meis2, a proximal limb-patterning gene, and Hoxd11, a gene involved in digit elongation. Both genes are significantly over-expressed in the developing bat forelimb as compared to the hindlimb and equivalently staged mouse forelimbs.
Project description:RNA-seq analysis of the effect of CRISPR/Cas9-induced CTCF binding sites deletions on gene expression. We studied E12.5 distal or proximal forelimbs of wildtype and mutant alleles.
Project description:Polycomb group (PcG) proteins play a pivotal role in silencing developmental genes and help to maintain various stem and precursor cells and regulate their differentiation. PcG factors also regulate dynamic and complex regional specification, particularly in mammals, but this activity is mechanistically not well understood. In this study, we focused on proximal-distal (PD) patterning of the mouse forelimb bud to elucidate how PcG factors contribute to a regional specification process that depends on developmental signals. Depletion of the RING1 proteins RING1A (RING1) and RING1B (RNF2), which are essential components of Polycomb repressive complex 1 (PRC1), led to severe defects in forelimb formation along the PD axis. We show that preferential defects in early distal specification in Ring1A/B-deficient forelimb buds accompany failures in the repression of proximal signal circuitry bound by RING1B, including Meis1/2, and the activation of distal signal circuitry in the prospective distal region. Additional deletion of Meis2 induced partial restoration of the distal gene expression and limb formation seen in the Ring1A/B-deficient mice, suggesting a crucial role for RING1-dependent repression of Meis2 and likely also Meis1 for distal specification. We suggest that the RING1-MEIS1/2 axis is regulated by early PD signals and contributes to the initiation or maintenance of the distal signal circuitry. This SuperSeries is composed of the SubSeries listed below.
Project description:Polycomb group (PcG) proteins play a pivotal role in epigenetically silencing development-related genes, restricting their expression to appropriate tissues. However, in some instances PcG target genes must also be dynamically regulated in response to developmental signals encountered during morphogenesis. Here we examine the role of PcG factors in early forelimb bud patterning, a process that relies on various morphogenetic signals. Depletion of Ring1 proteins, which are essential components of Polycomb repressive complex-1 (PRC1), led to dramatic deficiencies in forelimb formation and proximal-distal regionalization. Gene expression analysis identified Meis2 and Meis1 as critical PRC1 targets genes in early distal specification, with PcG proteins counteracting retinoic acid (RA) signaling to control their expression. Importantly, in this system, PcG factors appear to function by adjusting the threshold for RA signaling, revealing an unexpected role of polycomb proteins in dynamic gene regulation during development.
Project description:The bat offers an alternative paradigm to the standard mouse and chick model of limb development as it has extremely divergent forelimbs (long digits supporting a wing) and hindlimbs (short digits and claws) due the distinct requirements of both aerial and terrestrial locomotion. We used a cross-species microarray approach to identify differentially expressed (DE) genes between the bat (Minniopterus natalensis) forelimb and hindlimb autopods at Carollia developmental stages (CS) 16 and CS17, and between the bat (CS17) and mouse (E13.5) forelimb autopods. Several DE genes were identified, including two homeobox genes, Meis2, a proximal limb-patterning gene, and Hoxd11, a gene involved in digit elongation. Both genes are significantly over-expressed in the developing bat forelimb as compared to the hindlimb and equivalently staged mouse forelimbs. A reference design was used in this microarray experiment. A pool of left and right mouse forelimb autopods from 24 embryos was used as the reference sample. This sample was directly compared to individual CS16 and CS17 bat fore- and hindlimbs (left and right of one individual pooled) that were classified as the test conditions. Four experimental sessions were performed using an independently amplified mouse reference pool and 4 biological repeats for the bat limbs. These samples were co-hybridised to OPERON Mouse OpArray (ver. 4.0) spotted oligonucleotide slides to perform a competitive Cross-Species Hybridisation experiment. The bat aRNA (test) samples were labelled with Cy3 dye (green signal), the mouse aRNA (reference) sample was labelled with Cy5 dye (red signal).
Project description:This study aims to look at gene expresion profiles between wildtype and Bapx1 knockout cells of the forelimbs in a E12.5 mouse embryo. Instead of looking at the whole forelimbs, only cells expressing Bapx1 were sorted by Fluroscent Activated Cell Sorting (FACS) and subjected to expression profiling by microarray.
Project description:Suppression of Meis genes in the distal limb bud is required for Proximal-Distal (PD) specification of the forelimb. Polycomb group (PcG) factors play a role in downregulation of retinoic acid (RA)-related signals in the distal forelimb bud, causing Meis repression. It is, however, not known if downregulation of RA-related signals and PcG-mediated proximal genes repression are functionally linked. Here, we reveal that PcG factors and RA-related signals antagonize each other to polarize Meis2 expression along the PD axis. With mathematical modeling and simulation, we propose that PcG factors are required to adjust the threshold for RA-related signaling to regulate Meis2 expression. Finally, we show that a variant Polycomb repressive complex 1 (PRC1), incorporating PCGF3 and PCGF5, represses Meis2 expression in the distal limb bud. Taken together, we reveal a previously unknown link between PcG proteins and downregulation of RA-related signals to mediate the phase transition of Meis2 transcriptional status during forelimb patterning.
Project description:Polycomb group (PcG) proteins play a pivotal role in epigenetically silencing development-related genes, restricting their expression to appropriate tissues. However, in some instances PcG target genes must also be dynamically regulated in response to developmental signals encountered during morphogenesis. Here we examine the role of PcG factors in early forelimb bud patterning, a process that relies on various morphogenetic signals. Depletion of Ring1 proteins, which are essential components of Polycomb repressive complex-1 (PRC1), led to dramatic deficiencies in forelimb formation and proximal-distal regionalization. Gene expression analysis identified Meis2 and Meis1 as critical PRC1 targets genes in early distal specification, with PcG proteins counteracting retinoic acid (RA) signaling to control their expression. Importantly, in this system, PcG factors appear to function by adjusting the threshold for RA signaling, revealing an unexpected role of polycomb proteins in dynamic gene regulation during development. [Affymetrix] Mouse E10.5 forelimb buds of Ring1A-KO, Ring1A/B-dKO and RA-treated wild type were used for RNA extraction and hybridization on Affymetrix microarrays. [Agilent] ChIP analysis of mouse E10.5 whole forelimb buds against anti-H3K27me3 antibody.
Project description:Despite the importance of Hox genes in patterning the mouse embryo, few target genes of the Hox transcription factors have been identified. To search for HoxD targets we contrasted gene expression profiles in the presence and absence of the HoxD genes in two tissues where these genes are important in embryonic patterning-the genital bud and the distal domain of the limb. The Del9 mutant, in which all nine HoxD genes are absent, shows perturbed digit and genital morphogenesis. Therefore we used Affymetrix GeneChip arrays to compare gene expression in forelimb autopods and genital buds from wild type and homozygous Del9 E12.5 embryos.