Podcasts about munich enu

Background: Clinical chemical blood analysis including plasma electrolytes is routinely carried out for the diagnosis of various organ diseases. Phenotype-driven N-ethyl-N-nitrosourea (ENU) mouse mutagenesis projects used plasma electrolytes as parameters for the generation of novel animal models for human diseases. Methods: Here, we retrospectively evaluated the use of the plasma electrolytes calcium, chloride, inorganic phosphorus, potassium and sodium in the Munich ENU mouse mutagenesis project where clinical chemical blood analysis was carried out on more than 20,000 G1 and G3 offspring of chemically mutagenized inbred C3H mice to detect dominant and recessive mutations leading to deviations in various plasma parameter levels. Results: We identified a small number of animals consistently exhibiting altered plasma electrolyte values. Transmission of the phenotypic deviations to the subsequent generations led to the successful establishment of mutant lines for the parameters calcium and potassium. Published data from other phenotype-driven ENU projects also included only a small number of mutant lines which were generated according to altered plasma electrolyte levels. Conclusion: Thus, use of plasma electrolytes detected few mouse mutants in ENU projects compared to other clinical chemical blood parameters.

Background/Aim: Phenotype-driven screening of a great pool of randomly mutant mice and subsequent selection of animals showing symptoms equivalent to human kidney diseases may result in the generation of novel suitable models for the study of the pathomechanisms and the identification of genes involved in kidney dysfunction. Methods: We carried out a large-scale analysis of ethylnitrosourea (ENU)-induced mouse mutants for albuminuria by using qualitative SDS-polyacrylamide gel electrophoresis. Results: The primary albuminuria screen preceded the comprehensive phenotypic mutation analysis in a part of the mice of the Munich ENU project to avoid loss of mutant animals as a consequence of prolonged suffering from severe nephropathy. The primary screen detected six confirmed phenotypic variants in 2,011 G1 animals screened for dominant mutations and no variant in 48 G3 pedigrees screened for recessive mutations. Further breeding experiments resulted in two lines showing a low phenotypic penetrance of albuminuria. The secondary albuminuria screen was carried out in mutant lines which were established in the Munich ENU project without preceding primary albuminuria analysis. Two lines showing increased plasma urea levels were chosen to clarify if severe kidney lesions are involved in the abnormal phenotype. This analysis revealed severe albuminuria in mice which are affected by a recessive mutation leading to increased plasma urea and cholesterol levels. Conclusion: Thus, the phenotypic selection of ENU-induced mutants according to the parameter proteinuria in principle demonstrates the feasibility to identify nephropathy phenotypes in ENU-mutagenized mice. Copyright (C) 2005 S. Karger AG, Basel.

Phenotypic and genotypic characterization of the ENU-induced mutant mouse line HST001 for use in nephrological research A dominant mutation was established in the line HST001 within the Munich ENU mouse mutagenesis project. On the genetic background of the inbred strain C3H heterozygous mutant mice showed a pathological increase of the plasma urea concentration. The phenotypic characterization of the mutant line included the measurement of body and organ weights, food intake and a broad spectrum of clinical chemical and hematological parameters as well as histological investigations of inner organs. For those examinations heterozygous mutant mice were mated to C3H mice and the offspring were divided in the two groups of mutant and wildtype littermates according to the concentration of plasma urea. The mutation showed complete phenotypic penetrance in all generations examined. In addition the genomic localization of the causative mutation was determined by linkage analysis. At the age of 4 weeks the body weight of the mutant mice and the wildtype mice showed no difference. After 6 weeks the mutant mice grew more slowly leading to a significantly lower body weight compared to the wildtype littermates. At the age of 26 weeks the body weight of mutant mice was about 20% reduced as compared to controls. Mutants also showed a reduction of the nose-rump-length and the body fat content. Regarding the relative organ weights the mutant mice showed significantly higher values for the spleen and the brain. The clinical-chemical and hematological parameters were determined in the animals at the age of 12, 18 and 24 weeks. The mutant mice had significantly higher plasma concentrations of urea and total protein as well as a higher activity of the alkaline phosphatase. Beside that they showed lower plasma concentrations of triglycerides and glucose and a lower activity of amylase than the wildtype mice. The mutants showed increasing plasma urea levels whereas the levels decreased in the controls. At the age of 24 weeks the mutants showed levels, which were two-fold higher than those of the controls. The histopathological investigation of the kidneys did not reveal any alterations, which could to explain the pathological increase of the plasma urea concentration in the mutant mice. However urea secretion via the kidneys was impaired, since the mutants showed significantly lower urine urea levels compared to the wildtype mice. The investigation of the hematological parameters resulted in the occurrence of altered values in the 18 und 24 weeks old mice. The mutant mice showed reduced numbers 91 of erythrocytes as well as decreased values for hemoglobin concentration, mean corpuscular volume and hematocrit. The hitherto existing results of the linkage analysis of the mutation in the genome using polymorphic microsatellite markers showed that the mutation maps to chromosome 7. This result has to be confirmed and specified by using additional markers and a larger number of animals.