Project description:The study compares two cell populations one where Etv2 is expressed and other lacks Etv2 expression. The cells from wild-type E9.5 hindlimbs , cells from Shh-EGFP E10.5 anterior hindlimbs , EGFP+ cells from Shh-EGFP E10.5 posterior hindlimbs, and EYFP+ cells from Etv2-EYFP transgenic E10.5 hindlimbs and forelimbs were collected and processed
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:The regulatory specificity of enhancers and their interaction with gene promoters is thought to be controlled by their sequence and the binding of transcription factors. By studying Pitx1, a regulator of hindlimb development, we show that dynamic changes in chromatin conformation can restrict the activity of enhancers. Inconsistent with its hindlimb-restricted expression, Pitx1 is controlled by an enhancer (Pen) that shows activity in forelimbs and hindlimbs. By Capture Hi-C and three-dimensional modeling of the locus, we demonstrate that forelimbs and hindlimbs have fundamentally different chromatin configurations, whereby Pen and Pitx1 interact in hindlimbs and are physically separated in forelimbs. Structural variants can convert the inactive into the active conformation, thereby inducing Pitx1 misexpression in forelimbs, causing partial arm-to-leg transformation in mice and humans. Thus, tissue-specific three-dimensional chromatin conformation can contribute to enhancer activity and specificity in vivo and its disturbance can result in gene misexpression and disease.
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:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:Hoxd genes are important for limb development in all tetrapods examined thus far. In mouse, they are controlled by a complex bimodal regulation, which regulates first the proximal patterning, then the distal structure, allowing at the same time the formation of the wrist and ankle articulations. We analyzed the existence of this regulatory mechanism in chicken, i.e. in an animal where large morphological differences exist between fore- and hindlimbs. We report that while this bimodal regulation is globally conserved between mammals and avian, some important modifications evolved at least between these two model systems, in particular regarding the activity of specific enhancer and the position of the TAD boundary and the forelimb versus hindlimb comparative regulations. Some aspects of these regulations seem to be more conserved between chick and bats than with the mouse situation, which may relate to the extent to which forelimbs and hindlimbs of these various animals differ in their functions.
Project description:Hoxd genes are important for limb development in all tetrapods examined thus far. In mouse, they are controlled by a complex bimodal regulation, which regulates first the proximal patterning, then the distal structure, allowing at the same time the formation of the wrist and ankle articulations. We analyzed the existence of this regulatory mechanism in chicken, i.e. in an animal where large morphological differences exist between fore- and hindlimbs. We report that while this bimodal regulation is globally conserved between mammals and avian, some important modifications evolved at least between these two model systems, in particular regarding the activity of specific enhancer and the position of the TAD boundary and the forelimb versus hindlimb comparative regulations. Some aspects of these regulations seem to be more conserved between chick and bats than with the mouse situation, which may relate to the extent to which forelimbs and hindlimbs of these various animals differ in their functions.
Project description:Hoxd genes are important for limb development in all tetrapods examined thus far. In mouse, they are controlled by a complex bimodal regulation, which regulates first the proximal patterning, then the distal structure, allowing at the same time the formation of the wrist and ankle articulations. We analyzed the existence of this regulatory mechanism in chicken, i.e. in an animal where large morphological differences exist between fore- and hindlimbs. We report that while this bimodal regulation is globally conserved between mammals and avian, some important modifications evolved at least between these two model systems, in particular regarding the activity of specific enhancer and the position of the TAD boundary and the forelimb versus hindlimb comparative regulations. Some aspects of these regulations seem to be more conserved between chick and bats than with the mouse situation, which may relate to the extent to which forelimbs and hindlimbs of these various animals differ in their functions.
Project description:Hoxd genes are important for limb development in all tetrapods examined thus far. In mouse, they are controlled by a complex bimodal regulation, which regulates first the proximal patterning, then the distal structure, allowing at the same time the formation of the wrist and ankle articulations. We analyzed the existence of this regulatory mechanism in chicken, i.e. in an animal where large morphological differences exist between fore- and hindlimbs. We report that while this bimodal regulation is globally conserved between mammals and avian, some important modifications evolved at least between these two model systems, in particular regarding the activity of specific enhancer and the position of the TAD boundary and the forelimb versus hindlimb comparative regulations. Some aspects of these regulations seem to be more conserved between chick and bats than with the mouse situation, which may relate to the extent to which forelimbs and hindlimbs of these various animals differ in their functions.