Knockdown of the Drosophila Fused in Sarcoma (FUS) Homologue Causes Deficient Locomotive Behavior and Shortening of Motoneuron Terminal Branches

Mutations in the fused in sarcoma/translated in liposarcoma gene (FUS/TLS, FUS) have been identified in sporadic and familial forms of amyotrophic lateral sclerosis (ALS). FUS is an RNA-binding protein that is normally localized in the nucleus, but is mislocalized to the cytoplasm in ALS, and comprises cytoplasmic inclusions in ALS-affected areas. However, it is still unknown whether the neurodegeneration that occurs in ALS is caused by the loss of FUS nuclear function, or by the gain of toxic function due to cytoplasmic FUS aggregation. Cabeza (Caz) is a Drosophila orthologue of human FUS. Here, we generated Drosophila models with Caz knockdown, and investigated their phenotypes. In wild-type Drosophila, Caz was strongly expressed in the central nervous system of larvae and adults. Caz did not colocalize with a presynaptic marker, suggesting that Caz physiologically functions in neuronal cell bodies and/or their axons. Fly models with neuron-specific Caz knockdown exhibited reduced climbing ability in adulthood and anatomical defects in presynaptic terminals of motoneurons in third instar larvae. Our results demonstrated that decreased expression of Drosophila Caz is sufficient to cause degeneration of motoneurons and locomotive disability in the absence of abnormal cytoplasmic Caz aggregates, suggesting that the pathogenic mechanism underlying FUS-related ALS should be ascribed more to the loss of physiological FUS functions in the nucleus than to the toxicity of cytoplasmic FUS aggregates. Since the Caz-knockdown Drosophila model we presented recapitulates key features of human ALS, it would be a suitable animal model for the screening of genes and chemicals that might modify the pathogenic processes that lead to the degeneration of motoneurons in ALS

Molecular Determinants and Genetic Modifiers of Aggregation and Toxicity for the ALS Disease Protein FUS/TLS

A combination of yeast genetics and protein biochemistry define how the fused in sarcoma (FUS) protein might contribute to Lou Gehrig's disease

CLIPing the brain:studies of protein-RNA interactions important for neurodegenerative disorders

The fate of an mRNA is largely determined by its interactions with RNA binding proteins (RBPs). Post-transcriptional processing, RNA stability, localisation and translation are some of the events regulated by the plethora of RBPs present within cells. Mutations in various RBPs cause several diseases of the central nervous system, including frontotemporal lobar degeneration, amyotrophic lateral sclerosis and fragile X syndrome. Here we review the studies that integrated UV-induced cross-linked immunoprecipitation (CLIP) with other genome-wide methods to comprehensively characterise the function of diverse RBPs in the brain. We discuss the technical challenges of these studies and review the strategies that can be used to reliably identify the RNAs bound and regulated by an RBP. We conclude by highlighting how CLIP and related techniques have been instrumental in addressing the role of RBPs in neurologic diseases. This article is part of a Special Issue entitled: RNA and splicing regulation in neurodegeneration. © 2013

ATTEINTES NEUROLOGIQUES ET PULMONAIRES ASSOCIEES AUX HEPATITES AUTO-IMMUNES (A PROPOS DE DEUX OBSERVATIONS)

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

La réaction de Mukaiyama vinylogue catalytique et asymétrique (méthodologie et applications synthétiques)

La thématique générale dans laquelle s inscrit le travail présenté dans ce manuscrit est l étude de la réaction de Mukaiyama vinylogue catalytique et asymétrique(MVCA). Cette réaction désigne l addition d un diénolate silylé sur un composé carbonylé de type aldéhyde ou cétone. Nos conditions expérimentales conduisent à l obtention de -lactones a,b-insaturées. La première partie de la discussion concerne l étude méthodologique réalisée pour améliorer l étape de purification du diénolate silylé et pour s affranchir de sa synthèse par l utilisation d équivalents synthétiques comme un allène ester 2,4-diènique. Cette étude se poursuit avec l utilisation de notre méthodologie MVCA à de nouveaux substrats carbonylés : les imines et les cétones. La deuxième partie de la discussion concerne deux applications synthétiques de la méthodologie MVCA : la synthèse d acides aminés g-hydroxylés protégés et une approche vers la synthèse du fragment C1-C9 d un analogue de la rhizoxine D. Tout d abord, la synthèse d acides aminés g-hydroxylés protégés sous forme de carbamate qui comporte deux étapes clés : l utilisation d un réaction de Mukaiyama vinylogue catalytique et asymétrique diastéréo- et énantiosélective, puis la cyclisation diastéréosélective de 1,5-dicarbamates catalysée par du Pd(0). Lors de la synthèse vers le fragment C1-C9 d un analogue de la rhizoxine D, les possibilités de fonctionnalisation de la double liaison d une -lactone a,b-insaturée ont été envisagées via une réaction de Mukaiyama vinylogue Michael ou une réaction d allylation.The general theme of this work is the study of the Catalytic and Asymmetric Vinylogous Mukaiyama reaction (CAVM). This reaction consists of the addition of a silylated dienolate on a carbonyl compound such as aldehyde or ketone. Our experimental conditions lead to the formation of a,b-unsatured lactones. The first part of the discussion focuses on the methodological study about the purification of the silylated dienolate and the strategies to avoid its synthesis using a synthetic equivalent such as an allenic ester or a 2,4-dienic ester. Then, we expose the scope extension of our CAVM methodology to new substrates : ethyl-ketones and imines. The second part of the discussion focuses have two synthetic applications: the synthesis of g-hydroxylated a-aminonacids and an approach toward the synthesis of the C1-C9 fragment of an analogue of the rhizoxine D. The two key step of the g-hydroxylated a-aminonacid synthesis are a diastereo- and enantioselective CAVM reaction, and a diastereoselective Pd(0)-catalysed cyclisation of 1,5-diacabamates. The synthesis of the C1-C9 fragment of an analogue of the rhizoxine D was a good opportunity to study the possibility to fonctionnalise the double bond of a, b-unsatured lactones by a vinylogous Mukaiyama Michael or an allylation.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Synthetic approaches to alpha,beta-unsaturated delta-lactones and lactols

International audienc

Alpha, beta-unsaturated delta-lactones from copper-catalyzed asymmetric vinylogous Mukaiyama reactions of aldehydes : scope and mechanistic insights.

International audienc

The pearl oyster (Pinctada margaritifera) aquaculture in French Polynesia and the indirect impact of long-distance transfers and collection-culture site combinations on pearl quality traits

In French Polynesia, the P. margaritifera pearl aquaculture industry is spread over a vast area, as large as Europe. All the oysters for this the highly economically important activity are supplied from just a few collection lagoons, but they are grown in numerous sites across three archipelagos (Gambier, Society and Tuamotu). Many oyster transfers thus indirectly bring about grafting combinations mixing different geographic origins and production sites. This study aims to examine the impact of such graft combinations on cultured pearl quality traits. For this, six homogeneous and standardised experimental graft combinations (N = 6197) were conducted at commercial scale in the two growing locations the most frequently used in French Polynesia: Arutua atoll (Tuamotu) and Mangareva island (Gambier), using oysters supplied from by the top three collection sites: Ahe, Takapoto and Mangareva lagoons. At harvest, four main pearl quality traits: nacre weight deposition speed, pearl colour components (darkness level and green overtone), grade and shape categories were recorded by a professional sorter from the Tahiti auction and compared. Results revealed effects of the combinations of oyster origin and grow-out location, with: 1) significant origin ´ site interaction for nacre weight deposition speed; 2) colour variation at intra- and inter-site scales, with Ahe origin producing the most dark pearls and Gambier highest rate of the attractive green coloured pearls; and 3) higher grade categories for the Gambier origin and rearing location. These oyster-site combination effects highlight the benefit for the Polynesian pearl industry of switching from a mono-site/ company production system to a new multi-site production strategy to maximize overall cultured pearl quality expressio

Potential combinations of mabé, keshi and cultured pearl production from colourful hatchery-produced Pinctada margaritifera

International audienceAquaculture of nacreous gems, such as cultured pearls, mabé or keshi, is done mostly using different mollusc species grown in countries of the Indo-Pacific region. To date, no single species has been exploited for the simultaneous generation of more than one of these bioproducts, but all require animals with colourful shells. Historically, Pinctada species have mainly been used for nucleated pearl production, selecting the rarer colourful individuals to be used as graft donors. By contrast, colourful Pteria species have mostly been used for mabé production, as the grafting operation for pearl production is associated with low yield. In this study, we report the potential for cumulating cultured pearl and mabé (MP), or keshi and mabé (MK) production, using a colourful hatchery-produced G2 family of P. margaritifera. For these trials, MP and MK combinations were compared with the operations to produce pearls (P), mabé (M) or keshi (K) alone in an experimental design using groups of small and large recipients from the G2 family. Results showed no significant impact of combining operation types on subsequent pearl weight, keshi weight, or mabé thickness within recipient oyster size group. By contrast, significant differences were observed between the large and small recipients. The small group produced the thickest mabé, while the large group produced the heaviest pearls and keshi. These contrasting results revealed: 1) the relative independence between the two tissues capable of biomineralisation activities, the mantle (shell and mabé growth) and the pearl sac (pearl or keshi growth); 2) the potential compensatory growth of the small recipient oyster group, which had the highest shell growth performance; and 3) the regulation capacity of the larger oyster group of pearl sac activity. With the same growing area and number of cultured oysters, it would be possible for the P. margaritifera pearl industry to benefit from hatchery propagation of selected colourful shell and produce valuable keshi and mabé together with cultured pearls