ABSTRACT
The German Mouse Clinic (GMC) is a large scale phenotyping center where mouse mutant lines are analyzed in a standardized and comprehensive way. The result is an almost complete picture of the phenotype of a mouse mutant line--a systemic view. At the GMC, expert scientists from various fields of mouse research work in close cooperation with clinicians side by side at one location. The phenotype screens comprise the following areas: allergy, behavior, clinical chemistry, cardiovascular analyses, dysmorphology, bone and cartilage, energy metabolism, eye and vision, host-pathogen interactions, immunology, lung function, molecular phenotyping, neurology, nociception, steroid metabolism, and pathology. The German Mouse Clinic is an open access platform that offers a collaboration-based phenotyping to the scientific community (www.mouseclinic.de). More than 80 mutant lines have been analyzed in a primary screen for 320 parameters, and for 95% of the mutant lines we have found new or additional phenotypes that were not associated with the mouse line before. Our data contributed to the association of mutant mouse lines to the corresponding human disease. In addition, the systemic phenotype analysis accounts for pleiotropic gene functions and refines previous phenotypic characterizations. This is an important basis for the analysis of underlying disease mechanisms. We are currently setting up a platform that will include environmental challenge tests to decipher genome-environmental interactions in the areas nutrition, exercise, air, stress and infection with different standardized experiments. This will help us to identify genetic predispositions as susceptibility factors for environmental influences.
Subject(s)
Biomedical Research/methods , Disease Models, Animal , Mice, Mutant Strains/genetics , Phenotype , Animal Husbandry , Animals , Biomedical Research/standards , Germany , Mice , Mice, Mutant Strains/growth & development , Quality ControlABSTRACT
Hemizygous deletions on chromosome 22q11.2 result in developmental disorders referred to as DiGeorge syndrome (DGS)/velocardiofacial syndrome (VCFS). We report the isolation of a novel gene, PCQAP (PC2 glutamine/Q-rich-associated protein), that maps to the DiGeorge typically deleted region and encodes a protein identified as a subunit of the large multiprotein complex PC2. PC2 belongs to the family of the human Mediator complexes, which exhibit coactivator function in RNA polymerase II transcription. Furthermore, we cloned the homologous mouse Pcqap cDNA. There is 83% amino acid identity between the human and the mouse predicted protein sequences, with 96% similarity at the amino- and carboxy-terminal ends. To assess the potential involvement of PCQAP in DGS/VCFS, its developmental expression pattern was analyzed. In situ hybridization of mouse embryos at different developmental stages revealed that Pcqap is ubiquitously expressed. However, higher expression was detected in the frontonasal region, pharyngeal arches, and limb buds. Moreover, analysis of subjects carrying a typical 22q11 deletion revealed that the human PCQAP gene was deleted in all patients. Many of the structures affected in DGS/VCFS evolve from Pcqap-expressing cells. Together with the observed haploinsufficiency of PCQAP in DGS/VCFS patients, this finding is consistent with a possible role for this novel Mediator subunit in the development of some of the structures affected in DGS/VCFS.
Subject(s)
Carrier Proteins/genetics , Chromosomes, Human, Pair 22/genetics , DiGeorge Syndrome/genetics , Transcription Factors/genetics , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , Cell Line , Chromosome Mapping , Cloning, Molecular , DNA Mutational Analysis , DNA, Complementary/chemistry , DNA, Complementary/genetics , DNA, Complementary/isolation & purification , Embryo, Mammalian/metabolism , Exons , Female , Gene Expression , Genes/genetics , Glutamine/genetics , HeLa Cells , Humans , In Situ Hybridization , In Situ Hybridization, Fluorescence , Introns , Jurkat Cells , Male , Mediator Complex , Mice , Molecular Sequence Data , Mutation , Polymorphism, Single Nucleotide , Protein Subunits , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Tissue Distribution , Tumor Cells, CulturedABSTRACT
In the embryo of Arabidopsis thaliana (L.) Heynh., formation of the hypocotyl/root axis is initiated at the early-globular stage, recognizable as oriented expansion of formerly isodiametric cells. The process depends on the activity of the gene MONOPTEROS (MP); mp mutant embryos fail to produce hypocotyl and radicle. We have analyzed the morphology and anatomy of mp mutant plants throughout the Arabidopsis life cycle. Mutants form largely normal rosettes and root systems, but inflorescences either fail to form lateral flowers or these flowers are greatly reduced. Furthermore, the auxin transport capacity of inflorescence axes is impaired and the vascular strands in all analyzed organs are distorted. These features of the mutant phenotype suggest that the MP gene promotes cell axialization and cell file formation at multiple stages of plant development.