Loss of p21-activated kinase Mbt/PAK4 causes Parkinson-like phenotypes in Drosophila.

Parkinson's disease (PD) provokes bradykinesia, resting tremor, rigidity and postural instability, and also non-motor symptoms such as depression, anxiety, sleep and cognitive impairments. Similar phenotypes can be induced in Drosophila melanogaster through modification of PD-relevant genes or the administration of PD-inducing toxins. Recent studies correlated deregulation of human p21-activated kinase 4 (PAK4) with PD, leaving open the question of a causative relationship of mutations in this gene for manifestation of PD symptoms. To determine whether flies lacking the PAK4 homolog Mushroom bodies tiny (Mbt) show PD-like phenotypes, we tested for a variety of PD criteria. Here, we demonstrate that mbt mutant flies show PD-like phenotypes including age-dependent movement deficits, reduced life expectancy and fragmented sleep. They also react to a stressful situation with higher immobility, indicating an influence of Mbt on emotional behavior. Loss of Mbt function has a negative effect on the number of dopaminergic protocerebral anterior medial (PAM) neurons, most likely caused by a proliferation defect of neural progenitors. The age-dependent movement deficits are not accompanied by a corresponding further loss of PAM neurons. Previous studies highlighted the importance of a small PAM subgroup for age-dependent PD motor impairments. We show that impaired motor skills are caused by a lack of Mbt in this PAM subgroup. In addition, a broader re-expression of Mbt in PAM neurons improves life expectancy. Conversely, selective Mbt knockout in the same cells shortens lifespan. We conclude that mutations in Mbt/PAK4 can play a causative role in the development of PD phenotypes.

International randomised controlled trial for the treatment of newly diagnosed EWING sarcoma family of tumours - EURO EWING 2012 Protocol.

BACKGROUND: Although there have been multiple randomised trials in newly diagnosed Ewing sarcoma family of tumours (ESFT) and these have been conducted over many years and involved many international cooperative groups, the outcomes for all stages of disease have plateaued. Internationally, the standard treatment of ESFT is not defined, and there is a need to add new agents other than conventional chemotherapy to improve outcomes. This trial will compare two different induction/consolidation chemotherapy regimens: (1) vincristine, ifosfamide, doxorubicin and etoposide (VIDE) induction and vincristine, actinomycin D, ifosfamide or cyclophosphamide, or busulfan and mephalan (VAI/VAC/BuMel) consolidation and (2) vincristine, doxorubicin, cyclophosphamide, ifosfamide and etoposide (VDC/IE) induction and ifosfamide and etoposide, vincristine and cyclophosphamide, vincristine, actinomycin D and ifosfamide, or busulfan and mephalan (IE/VC/VAI/BuMel) consolidation (randomisation 1, or R1). A second randomisation (R2) will determine whether the addition of zoledronic acid to consolidation chemotherapy, as assigned at R1, is associated with improved clinical outcome. METHODS: EURO EWING 2012 is an international, multicentre, phase III, open-label randomised controlled trial. There are two randomisations: R1 and R2. Patients are randomly assigned at two different time points: at entry to the trial (R1) and following local control therapy (R2). The primary outcome measure is event-free survival. The secondary outcome measures include overall survival, adverse events and toxicity, histological response of the primary tumour, response of the primary tumour, regional lymph nodes or metastases (or both), and achievement of local control at the end of treatment. DISCUSSION: This study will establish which is the "standard regimen" of chemotherapy, taking into account both clinical outcomes and toxicity. This will form the chemotherapy backbone for future interventional studies where we may want to add new targeted agents. It will also determine the role of zoledronic acid in conjunction with the separate EE2008 trial. Any trial in ESFT needs to take into account the rarity of the tumour and consider that international cooperation is needed to provide answers in a timely manner. TRIAL REGISTRATION: Registered with EudraCT number 2012-002107-17 on 26 February 2012. Registered with ISRCTN number 54540667 on 4 November 2013.

A Similar Secretome Disturbance as a Hallmark of Non-pathogenic Botrytis cinerea ATMT-Mutants?

The gray mold fungus Botrytis cinerea is a necrotrophic pathogen able to infect hundreds of host plants, including high-value crops such as grapevine, strawberry and tomato. In order to decipher its infectious strategy, a library of 2,144 mutants was generated by random insertional mutagenesis using Agrobacterium tumefaciens-mediated transformation (ATMT). Twelve mutants exhibiting total loss of virulence toward different host plants were chosen for detailed analyses. Their molecular characterization revealed a single T-DNA insertion in different loci. Using a proteomics approach, the secretome of four of these strains was compared to that of the parental strain and a common profile of reduced lytic enzymes was recorded. Significant variations in this profile, notably deficiencies in the secretion of proteases and hemicellulases, were observed and validated by biochemical tests. They were also a hallmark of the remaining eight non-pathogenic strains, suggesting the importance of these secreted proteins in the infection process. In the twelve non-pathogenic mutants, the differentiation of infection cushions was also impaired, suggesting a link between the penetration structures and the secretion of proteins involved in the virulence of the pathogen.

Multimerization of Drosophila sperm protein Mst77F causes a unique condensed chromatin structure.

Despite insights on the cellular level, the molecular details of chromatin reorganization in sperm development, which involves replacement of histone proteins by specialized factors to allow ultra most condensation of the genome, are not well understood. Protamines are dispensable for DNA condensation during Drosophila post-meiotic spermatogenesis. Therefore, we analyzed the interaction of Mst77F, another very basic testis-specific protein with chromatin and DNA as well as studied the molecular consequences of such binding. We show that Mst77F on its own causes severe chromatin and DNA aggregation. An intrinsically unstructured domain in the C-terminus of Mst77F binds DNA via electrostatic interaction. This binding results in structural reorganization of the domain, which induces interaction with an N-terminal region of the protein. Via putative cooperative effects Mst77F is induced to multimerize in this state causing DNA aggregation. In agreement, overexpression of Mst77F results in chromatin aggregation in fly sperm. Based on these findings we postulate that Mst77F is crucial for sperm development by giving rise to a unique condensed chromatin structure.

Three levels of regulation lead to protamine and Mst77F expression in Drosophila.

Differentiation from a haploid round spermatid to a highly streamlined, motile sperm requires temporal and spatial regulation of the expression of numerous proteins. One form of regulation is the storage of translationally repressed mRNAs. In Drosophila spermatocytes, the transcription of many of these translationally delayed mRNAs during spermiogenesis is in turn directly or indirectly regulated by testis-specific homologs of TATA-box-binding-protein-associated factors (tTAFs). Here we present evidence that expression of Mst77F, which is a specialized linker histone-like component of sperm chromatin, and of protamine B (ProtB), which contributes to formation of condensed sperm chromatin, is regulated at three levels. Transcription of Mst77F is guided by a short, promoter-proximal region, while expression of the Mst77F protein is regulated at two levels, early by translational repression via sequences mainly in the 5' part of the ORF and later by either protein stabilization or translational activation, dependent on sequences in the ORF. The protB gene is a direct target of tTAFs, with very short upstream regulatory regions of protB (-105 to +94 bp) sufficient for both cell-type-specific transcription and repression of translation in spermatocytes. In addition, efficient accumulation of the ProtB protein in late elongating spermatids depends on sequences in the ORF. We present evidence that spermatocytes provide the transacting mechanisms for translational repression of these mRNAs, while spermatids contain the machinery to activate or stabilize protamine accumulation for sperm chromatin components. Thus, the proper spatiotemporal expression pattern of major sperm chromatin components depends on cell-type-specific mechanisms of transcriptional and translational control.