Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Polyglutamine Atrophin provokes neurodegeneration in Drosophila

ABSTRACT: Dentatorubral-pallidoluysian Atrophy (DRPLA) is a human polyQ disease caused by the expansion of a CAG strech in the atrophin-1 (at-1) gene. In all vertebrates, a second atrophin gene (at-2) is present and it encodes a related protein void of polyQ tracks. In D.melanogaster there is one conserved Atrophin (Atro) gene, ubiquitously expressed, which contains all functional domains of vertebrate Atrophins, including two polyQ stretches. To understand to what extent transcriptional alterations cause neurodegeneration and are linked to the normal functions of Atrophin, we performed a genome wide transcriptional profiling in our Drosophila models, focusing on primary events that precede neurodegeneration. We have found that polyQ Atro downregulates fat, which protects from neurodegeneration and Atrophin toxicity trhough the Hippo kinase cascade. Neurodegeneration progression caused by poly glutamine expansions of the Atro gene is measured by mRNA expression profiles in 4 D.melanogaster genotypes: in wild-type animals (controls), animals constitutively expressing the wild-type Atro transgene, animals constitutively expressing the polyQ expanded Atro transgenes A66QC and A75QN. The expressions of the Atro genes are under a GMR-Gal4 driver repressed by a Gal80 universal repressor sensitive to temperature. When flies are raised at 18 C, the transgenes are not expressed, but their expression is switched on when they are shifted to the ageing protocol at 29 C at time point day 0. The neurodegeneration is assessed after 2 and 14 days post-high-temperature shift.

ORGANISM(S): Drosophila melanogaster

SUBMITTER: Eric Blanc

PROVIDER: E-GEOD-26246 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

Polyglutamine Atrophin provokes neurodegeneration in Drosophila by repressing fat.

Napoletano Francesco F Occhi Simona S Calamita Piera P Volpi Vera V Blanc Eric E Charroux Bernard B Royet Julien J Fanto Manolis M

The EMBO journal 20110128 5

Large alterations in transcription accompany neurodegeneration in polyglutamine (polyQ) diseases. These pathologies manifest both general polyQ toxicity and mutant protein-specific effects. In this study, we report that the fat tumour suppressor gene mediates neurodegeneration induced by the polyQ protein Atrophin. We have monitored early transcriptional alterations in a Drosophila model of Dentatorubral-pallidoluysian Atrophy and found that polyQ Atrophins downregulate fat. Fat protects from ne ...[more]

PMID: 21278706

Similar Datasets

Project description:Spinocerebellar ataxia type 3 (SCA3) is one of the polyglutamine (polyQ) diseases, which are caused by a CAG repeat expansion within the coding region of the associated genes. The CAG repeat specifies glutamine, and the expanded polyQ domain with mutation confers dominant toxicity on the protein. Traditionally, studies have focused on protein toxicity in polyQ disease mechanisms. Recent findings, however, demonstrate that the CAG repeat RNA, which encodes the toxic polyQ protein, also contributes to the disease in Drosophila. To provide insight into the nature of the RNA toxicity, we extracted brain-enriched RNA from flies expressing a toxic CAG repeat mRNA (CAG100) and a non-toxic interrupted CAA/G mRNA repeat (CAA/G105) for microarray analysis. This approach identified a set of genes that are differentially expressed specifically in CAG100 flies. Four independent replicates of flies expressing CAG0, CAG100, or CAA/G105 by elav-GAL4 were collected at 3 days. The transgenes are DsRed with either (CAG0) no CAG repeat in the 3'UTR, (CAG100) a CAG repeat of 100 CAGs in the 3'UTR, or (CAA/G105) an interrupted CAA CAG repeat in the 3'UTR (ref: Li et al., Nature 453:1107) The transgenes were adjusted to match in mRNA expression such that CAG0 flies had one copy of the transgene, CAG100 flies had 5 copies, and CAA/G105 had two copies. Fly brain tissue (about 20 brains per sample, dissected from head capsule, eyes, lamina and outer medulla removed) was dissected in cold phosphate buffered saline (PBS) and stored in Trizol reagent (Invitrogen Corporation, Carlsbad, CA) at -80Ë?C. Total brain RNA was extracted and purified using TRIzol reagent (Invitrogen) and the RNeasy Mini system (Qiagen), and treated with RNase-free DNase I (Qiagen). To define genes whose expression is altered in response to a toxic CAG repeat RNA, we compared CAG100 flies with age-matched flies expressing CAG0. To exclude transcriptional changes in response to a non-toxic trinucleotide repeat, a second gene list was generated by comparing CAA/G105 flies with age-matched CAG0 flies.

Project description:This SuperSeries is composed of the following subset Series: GSE24992: Drosophila brain microRNA expression with age: miRNA profiling GSE25007: Drosophila brain gene expression with age: mRNA profiling GSE25008: Drosophila brain gene expression between wildtype and miR-34 null flies Refer to individual Series. Aging is the most prominent risk factor for human neurodegenerative disease, but underlying mechanisms that connect two processes are less well characterized. With age, the brain undergoes functional decline and perhaps degeneration. Such decline may not just contribute to normal aging, but also enhance susceptibility to and progression of age-related neurodegenerative diseases. Therefore, defining intrinsic factors and pathways that underline the normal integrity of the adult nervous system may lead to insights that potentially link aging and neurodegeneration. Here, we report a highly conserved microRNA (miRNA), miR-34, as a modulator of aging and neurodegeneration. Using Drosophila, we show that fly miR-34 expression is brain-enriched and strikingly upregulated with age. Functional studies reveal that, whereas animals without miR-34 are normal as young adults, upon aging, they gradually show late-onset deficits characteristic of accelerated brain aging; these include a transcriptional signature of aged animals, coupled with rapid functional decline, loss of brain integrity, followed by a catastrophic decline in adult viability. Moreover, upregulation of miR-34 protects against neurodegeneration induced by pathogenic human polyglutamine (polyQ) disease protein. We next reveal a dramatic effect of miR-34 to silence the Eip74EF gene of steroid hormone pathways in the adult, which is crucial to maintain the normal aging. Collectively, these data define a miR-34-mediated mechanism that specifically affects long-term integrity of the adult nervous system. miR-34 function in Drosophila may thus present a link that functionally connects aging and neurodegeneration. Our studies implicate essential roles of miRNA- dependent pathways in maintenance of the adult brain, disease pathogenesis and healthy aging.

Dataset Information

Polyglutamine Atrophin provokes neurodegeneration in Drosophila

Publications

Polyglutamine Atrophin provokes neurodegeneration in Drosophila by repressing fat.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets