Targeting of the Plzf gene in the rat by transcription activator-like effector nuclease results in caudal regression syndrome in spontaneously hypertensive rats

Recently, it has been found that spontaneous mutation Lx (polydactyly-luxate syndrome) in the rat is determined by deletion of a conserved intronic sequence of the Plzf (Promyelocytic leukemia zinc finger protein) gene. In addition, Plzf is a prominent candidate gene for quantitative trait loci (QTLs) associated with cardiac hypertrophy and fibrosis in the spontaneously hypertensive rat (SHR). In the current study, we tested the effects of Plzf gene targeting in the SHR using TALENs (transcription activator-like effector nucleases). SHR ova were microinjected with constructs pTAL438/439 coding for a sequence-specific endonuclease that binds to target sequence in the first coding exon of the Plzf gene. Out of 43 animals born after microinjection, we detected a single male founder. Sequence analysis revealed a deletion of G that resulted in frame shift mutation starting in codon 31 and causing a premature stop codon at position of amino acid 58. The Plzftm1Ipcv allele is semi-lethal since approximately 95% of newborn homozygous animals died perinatally. All homozygous animals exhibited manifestations of a caudal regression syndrome including tail anomalies and serious size reduction and deformities of long bones, and oligo- or polydactyly on the hindlimbs. The heterozygous animals only exhibited the tail anomalies. Impaired development of the urinary tract was also revealed: one homozygous and one heterozygous rat exhibited a vesico-ureteric reflux with enormous dilatation of ureters and renal pelvis. In the homozygote, this was combined with a hypoplastic kidney. These results provide evidence for the important role of Plzf gene during development of the caudal part of a body-column vertebrae, hindlimbs and urinary system in the rat

Distinct Impacts of Eda and Edar Loss of Function on the Mouse Dentition

The Eda-A1-Edar signaling pathway is involved in the development of organs with an ectodermal origin, including teeth. In mouse, mutants are known for both the ligand, Eda-A1 (Tabby), and the receptor, Edar (Downless). The adult dentitions of these two mutants have classically been considered to be similar. However, previous studies mentioned differences in embryonic dental development between EdaTa and Edardl-J mutants. A detailed study of tooth morphology in mutants bearing losses of functions of these two genes thus appears necessary to test the pattern variability induced by the developmental modifications. 3D-reconstructions of the cheek teeth have been performed at the ESRF (Grenoble, France) by X-ray synchrotron microtomography to assess dental morphology. The morphological variability observed in EdaTa and Edardl-J mutants have then been compared in detail. Despite patchy similarities, our detailed work on cheek teeth in EdaTa and Edardl-J mice show that all dental morphotypes defined in Edardl-J mice resolutely differ from those of EdaTa mice. This study reveals that losses of function of Eda and Edar have distinct impacts on the tooth size and morphology, contrary to what has previously been thought. The results indicate that unknown mechanisms of the Eda pathway are implicated in tooth morphogenesis. Three hypotheses could explain our results; an unexpected role of the Xedar pathway (which is influenced by the Eda gene product but not that of Edar), a more complex connection than has been appreciated between Edar and another protein, or a ligand-independent activity for Edar. Further work is necessary to test these hypotheses and improve our understanding of the mechanisms of development

The abandoned surface mining sites in the Czech Republic: mapping and creating a database with a GIS web application

Based on the vectorization of the 55-volume book series <i>the Quarry Inventories of the Czechoslovak Republic/Czechoslovak Socialist Republic</i>, published in the years 1932–1961, a new comprehensive database was built comprising 9958 surface mining sites of raw materials, which were active in the first half of the 20th century. The mapped area covers 40.9 % of the territory of the Czech Republic. For the purposes of visualization, a map application, the Quarry Inventories Online, was created that enables the data visualization

The abandoned surface mining sites in the Czech Republic: mapping and creating a database with a GIS web application

Based on the vectorization of the 55-volume book series <i>the Quarry Inventories of the Czechoslovak Republic/Czechoslovak Socialist Republic</i>, published in the years 1932–1961, a new comprehensive database was built comprising 9958 surface mining sites of raw materials, which were active in the first half of the 20th century. The mapped area covers 40.9 % of the territory of the Czech Republic. For the purposes of visualization, a map application, the Quarry Inventories Online, was created that enables the data visualization

Effect of the Tabby mutation on the dentition of mice

The X-linked hypohidrotic ectodermal dysplasia in man leads to dental defects and is homologous to the Tabby (Ta) mutation in mouse. We currently investigate the effects of the Ta mutation on odontogenesis. The incisor germ of Ta showed an abnormal size and shape, a change in the balance between prospective crown- and root-analogue tissues and retarded cytodifferentiation. Although the enamel organ in Ta incisors was smaller, a larger proportion of the dental papilla was covered by preameloblasts-ameloblasts. The independent development of the labial and lingual parts of the enamel organ in rodent lower incisor might reflect their heterogeneous origin, as demonstrated for the upper incisor. The mandibular cheek dentition in Ta mice exhibits large variations classified in five morphotypes, based on the tooth number, shape, size and position. In Ta embryos, the mesio-distal extent of the dental epithelium was similar to that in WT, but its segmentation was altered. These morphotypes could be explained by a tentative model suggesting that 1) the positions of tooth boundaries differ in Ta and WT molars and among the Ta morphotypes; 2) the tooth patterns are determined by the distal boundary of the most mesial tooth primordium while the distal teeth take advantage of the remaining dental epithelium; 3) one tooth primordium in Ta mice might derive from adjacent parts of two primordia in WT