Project description:Deficiency of the human short stature homeobox-containing gene (SHOX) has been identified in several disorders characterized by reduced height and skeletal anomalies such as Turner, Leri-Weill and Langer syndrome as well as idiopathic short stature. Although highly conserved in vertebrates, rodents lack a SHOX orthologue. Here, we compared gene expression profiles of wildtype and SHOX transgenic mouse limbs using microarray experiments to identify SHOX target genes in the developing limb. Limbs of E12.5 mouse embryos were dissected, fore- and hindlimbs were pooled and genotyped for RNA extraction. RNA from 2 to 4 littermates was pooled per genotype (Wildtype and SHOX transgene) and compared. In total, 2 microarray hybridization experiments were performed using RNA from 2 biological replicate samples for each genotype.
Project description:Deficiency of the human short stature homeobox-containing gene (SHOX) has been identified in several disorders characterized by reduced height and skeletal anomalies such as Turner, Leri-Weill and Langer syndrome as well as idiopathic short stature. Although highly conserved in vertebrates, rodents lack a SHOX orthologue. Here, we compared gene expression profiles of wildtype and SHOX transgenic mouse limbs using microarray experiments to identify SHOX target genes in the developing limb.
Project description:The SHOX2 transcription factor is required during mouse embryonic development for the formation of the proximal elements of limbs, the humerus and femur. The Shox2 gene is flanked by an extensive gene desert spanning over 500 kilobases (kb) that contains many evolutionarily conserved elements with predicted cis-regulatory activities. However, the transcriptional enhancer potential of the vast majority of these regions have not yet been assessed. Therefore, we have generated a map of the Shox2 regulatory landscape during limb development using chromosome conformation capture techniques (4C-Seq). We report that at least five enhancers, distributed over more than 500 kb interact with the Shox2 gene and control its expression in developing proximal limbs, as confirmed by transgenic mouse assays. Furthermore, by using two of the identified enhancer candidates as 4C-seq viewpoints, we also find evidence that three of these putative enhancers interact with each other as well as the Shox2 gene, perhaps forming a cooperative regulatory complex. We expect this study to provide insight into the regulation of the human SHOX gene, a closely-related homolog of Shox2, that is similarly flanked by a large gene desert. Notably, deletions within the gene desert downstream of human SHOX are implicated as a major cause of the limb deformities characteristic of Léri-Weill dyschondrosteosis.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
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