Parkinson's disease (PD) is an adult-onset movement disorder of largely unknown etiology. We have previously shown that loss-of-function mutations of the mitochondrial protein kinase PINK1 (PTEN induced putative kinase 1) cause the recessive PARK6 variant of PD. Now we generated a PINK1 deficient mouse and observed several novel phenotypes: A progressive reduction of weight and of locomotor activity selectively for spontaneous movements occurred at old age. As in PD, abnormal dopamine levels in the aged nigrostriatal projection accompanied the reduced movements. Possibly in line with the PARK6 syndrome but in contrast to sporadic PD, a reduced lifespan, dysfunction of brainstem and sympathetic nerves, visible aggregates of -synuclein within Lewy bodies or nigrostriatal neurodegeneration were not present in aged PINK1-deficient mice. However, we demonstrate PINK1 mutant mice to exhibit a progressive reduction in mitochondrial preprotein import correlating with defects of core mitochondrial functions like ATP-generation and respiration. In contrast to the strong effect of PINK1 on mitochondrial dynamics in Drosophila melanogaster and in spite of reduced expression of fission factor Mtp18, we show reduced fission and increased aggregation of mitochondria only under stress in PINK1-deficient mouse neurons. Thus, aging Pink1/ mice show increasing mitochondrial dysfunction resulting in impaired neural activity similar to PD, in absence of overt neuronal death. Transcriptome microarray data of Pink1-/- mouse brains in absence of a stressor, even at old age, show remarkably sparse dysregulations. See Gispert-S et al 2009 PLOS ONE.
Potentiation of neurotoxicity in double-mutant mice with Pink1 ablation and A53T-SNCA overexpression.
Age, Specimen part
View SamplesSpinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disorder, which is caused by an unstable CAG-repeat expansion in the SCA2 gene, that encodes a polyglutamine tract (polyQ-tract) expansion in ataxin-2 protein (ATXN2). The RNA-binding protein ATXN2 interacts with the poly(A)-binding protein PABPC1, localizing to ribosomes at the rough endoplasmic reticulum or to polysomes. Under cell stress ATXN2 and PABPC1 show redistribution to stress granules where mRNAs are kept away from translation and from degradation. It is unknown whether ATXN2 associates preferentially with specific mRNAs or how it modulates their processing. Here, we investigated Atxn2 knock-out (Atxn2-/-) mouse liver, cerebellum and midbrain regarding their RNA profile, employing oligonucleotide microarrays for screening and RNA deep sequencing for validation. Modest ~1.4-fold upregulations were observed for the level of many mRNAs encoding ribosomal proteins and other translation pathway factors. Quantitative reverse transcriptase PCR and immunoblots in liver tissue confirmed these effects and demonstrated an inverse correlation also with PABPC1 mRNA and protein. ATXN2 deficiency also enhanced phosphorylation of the ribosomal protein S6, while impairing the global protein synthesis rate, suggesting a block between the enhanced translation drive and the impaired execution. Furthermore, ATXN2 overexpression and deficiency retarded cell cycle progression. ATXN2 mRNA levels showed a delayed phasic twofold increase under amino acid and serum starvation, similar to ATXN3, but different from motor neuron disease genes MAPT and SQSTM1. ATXN2 mRNA levels depended particularly on mTOR signalling. Altogether the data implicate ATXN2 in the adaptation of mRNA translation and cell growth to nutrient availability and stress.
Genetic ablation of ataxin-2 increases several global translation factors in their transcript abundance but decreases translation rate.
Age, Specimen part
View SamplesAlpha-synuclein is an abundant protein implicated in synaptic function and plasticity, but the molecular mechanism of its action is not understood. Missense mutations and gene duplication/triplication events result in Parkinson's disease, a neurodegenerative disorder of old age with impaired movement and emotion control. Here, we systematically investigated the striatal as well as the cerebellar transcriptome profile of alpha-synuclein-deficient mice via a genome-wide microarray survey in order to gain hypothesis-free molecular insights into the physiological function of alpha-synuclein. A genotype-dependent, specific and strong downregulation of forkhead box P1 (Foxp1) transcript levels was observed in all brain regions from postnatal age until old age and could be validated by qPCR. In view of the co-localization and heterodimer formation of FOXP1 with FOXP2, a transcription factor with a well established role for vocalization, and the reported regulation of both alpha-synuclein and FOXP2 expression during avian song learning, we performed a detailed assessment of mouse movements and vocalizations in the postnatal period. While there was no difference in isolation-induced behavioral activity in these animals, the alpha-synuclein-deficient mice exhibited an increased production of isolation-induced ultrasonic vocalizations (USVs). This phenotype might also reflect the reduced expression of the anxiety-related GABA-A receptor subunit gamma 2 (Gabrg2) we observed. Taken together, we identified an early behavioral consequence of alpha-synuclein deficiency and accompanying molecular changes, which supports the notion that the neural connectivity of sound or emotion control systems is affected.
Alpha-synuclein deficiency affects brain Foxp1 expression and ultrasonic vocalization.
Age, Specimen part
View SamplesDppa4 (Developmental pluripotency-associated 4) has been identified in several highprofile screens as a gene that is expressed exclusively in pluripotent cells. It encodes a nuclear protein with a SAP-like domain and appears to be associated preferentially with transcriptionally active chromatin. Its exquisite expression pattern and results of RNA interference experiments have led to speculation that Dppa4, as well as its nearby homolog Dppa2, might play essential roles in embryonic stem cell function and/or germ cell development. To rigorously assess suggested roles, we have generated Dppa4-deficient and Dppa4/Dppa2 double-deficient ES cells, as well as mice lacking Dppa4. Contrary to predictions, we find that Dppa4 is completely dispensable for ES cell identity and germ cell development. Instead, loss of Dppa4 in mice results in late embryonic/peri-natal death and striking skeletal defects with partial penetrance. Thus, surprisingly, Dppa4-deficiency affects tissues, which never transcribed the gene, and at least some loss-of-function defects manifest phenotypically at an embryonic stage long after physiologic Dppa4 expression has ceased. Concomitant with targeted gene inactivation, we have introduced into the Dppa4 locus a red fluorescent marker (tandem-dimer RFP), which is compatible with GFP-based proteins and allows non-invasive visualization of pluripotent cells and reprogramming events.
The pluripotency-associated gene Dppa4 is dispensable for embryonic stem cell identity and germ cell development but essential for embryogenesis.
Cell line
View SamplesSpinocerebellar ataxia type 3 is a neurodegenerative disorder caused by the expansion of the polyglutamine repeat region within the ataxin-3 protein. The mutant protein forms intracellular aggregates in the brain. However, the cellular mechanisms causing toxicity are still poorly understood and there are currently no effective treatments. In this study we show that administration of a rapamycin ester, CCI-779, improves motor performance in a transgenic mouse model of SCA3. CCI-779 inhibits mammalian target of rapamycin (mTOR) and hence upregulates protein degradation by autophagy. CCI-779 reduces the number of aggregates seen in the brains of transgenic mice and decreases levels of cytosolic soluble mutant ataxin-3, while endogenous wild-type protein levels remain unaffected. CCI-779 is designed for long-term use in patients and therefore represents a possible therapeutic strategy for the treatment of SCA3. Using this disease model and treatment paradigm we employed a microarray approach to investigate transcriptional changes that might be important in the pathogenesis of SCA3. This approach identified Usp15, which showed expression changes at both the mRNA and protein level. Usp15 levels were also changed in mice expressing another mutant polyglutamine protein, huntingtin. In total we identified 16 transcripts that were decreased in transgenic ataxin-3 mice that were normalised following CCI-779 treatment, as the number of transcripts changed was low and the magnitude of these changes was small we suggest that transcriptional dysregulation may not be an important step in the primary pathogenesis of SCA3.
No associated publication
Sex, Specimen part
View SamplesPeriphilin is a protein which is involved in multiple processes in vivo, including terminal differentiation of keratinozytes as well as cell-cycle and cancer related functions. Here we generated mice with a targeted disruption of the periphilin-1 gene to explore its physiological role from an organismic perspective. In accordance with a ubiquitous expression of periphilin in the murine embryo, the homozygous deficiency of periphilin is lethal in early embryogenesis. We therefore characterized mice with a disruption of only one periphilin allele. As heterozygous periphilin knockout mice show no obvious histological alterations and have no apparent behavioural phenotypes, we compared whole transcriptome RNA expression profiles of total brain tissue of periphilin+/- knockout mice and wild type littermates for an in-depth analysis of heterozygous animals. In periphilin+/- knockout mice, 3 probe sets were indicative of significant differential expression (p 0.05, SLR 1 which is equivalent to 2 fold). Two of these probe sets (1438864_at and 1439170_at) refer to unannotated or unclassifiable genes. According to the NetAffx Analysis Center, the third probe set (1447831_s_at) is assigned to myotubularin related protein 7 (Mtmr7). The probe set, however, lies upstream of the Mtmr7 gene (Ensembl gene ENSMUSG00000039431), and its signal is therefore not representative for the Mtmr7 gene. Quantitative RT-PCR (qRT-PCR) analysis with a primer set specific for Mtmr7 confirmed that its expression is not altered in periphilin+/- knockout mice (relative expression compared to wild type: 0.924; p = 0.419). In summary, none of more than 45.000 covered transcripts is differentially expressed in periphilin+/- knockout mice in comparison to wild type littermates.
No associated publication
No sample metadata fields
View SamplesThe Hippocampus Consortium data set provides estimates of mRNA expression in the adult hippocampus of 99 genetically diverse strains of mice including 67 BXD recombinant inbred strains, 13 CXB recombinant inbred strains, a diverse set of common inbred strains, and two reciprocal F1 hybrids.
Genetics of the hippocampal transcriptome in mouse: a systematic survey and online neurogenomics resource.
Sex, Age, Specimen part
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Dynamic changes in 5-hydroxymethylation signatures underpin early and late events in drug exposed liver.
Sex, Specimen part, Treatment, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Homer1a is a core brain molecular correlate of sleep loss.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
STAT6 transcription factor is a facilitator of the nuclear receptor PPARγ-regulated gene expression in macrophages and dendritic cells.
Specimen part, Treatment, Subject, Time
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