Mutations in the TGFβ binding-protein-like domain 5 of FBN1 are responsible for acromicric and geleophysic dysplasias

Geleophysic (GD) and acromicric dysplasia (AD) belong to the acromelic dysplasia group and are both characterized by severe short stature, short extremities, and stiff joints. Although AD has an unknown molecular basis, we have previously identified ADAMTSL2 mutations in a subset of GD patients. After exome sequencing in GD and AD cases, we selected fibrillin 1 (FBN1) as a candidate gene, even though mutations in this gene have been described in Marfan syndrome, which is characterized by tall stature and arachnodactyly. We identified 16 heterozygous FBN1 mutations that are all located in exons 41 and 42 and encode TGFβ-binding protein-like domain 5 (TB5) of FBN1 in 29 GD and AD cases. Microfibrillar network disorganization and enhanced TGFβ signaling were consistent features in GD and AD fibroblasts. Importantly, a direct interaction between ADAMTSL2 and FBN1 was demonstrated, suggesting a disruption of this interaction as the underlying mechanism of GD and AD phenotypes. Although enhanced TGFβ signaling caused by FBN1 mutations can trigger either Marfan syndrome or GD and AD, our findings support the fact that TB5 mutations in FBN1 are responsible for short stature phenotypes.     

Association of a new Wolbachia strain with, and its effects on, Leptopilina victoriae, a virulent wasp parasitic to Drosophila spp

Wolbachia bacteria are ubiquitous intracellular bacteria of arthropods. Often considered reproductive parasites, they can benefit certain host species. We describe a new Wolbachia strain from Leptopilina victoriae, a Drosophila wasp. The strain is closely related to Wolbachia from Culex sp. Located to the posterior poles of oocytes, it manipulates its host's reproduction by inducing a male development type of cytoplasmic incompatibility. We also report its diverse effects on the wasp's life history traits.     

Nine polymorphic microsatellite loci from the psyllid Cacopsylla pruni (Scopoli), the vector of European stone fruit yellows

Cacopsylla pruni is the vector of European stone fruit yellows, a quarantine disease of Prunus trees. Nine polymorphic microsatellite markers were developed from enriched DNA libraries. Allelic variability was assessed in a collection of 149 females obtained from five localities covering a large geographical area in France. The number of detected alleles ranged from 8 to 37. Within the localities, observed and expected heterozygosities averaged across loci ranged from 0.39 to 0.55, and from 0.68 to 0.81, respectively. A heterozygote deficiency was detected for almost all loci, possibly due to a high null allele frequency. Other possible causes of the homozygote excess (mode of reproduction, inbreeding, assortative mating or Wahlund effect) are discussed. These variable microsatellite loci can provide tools to assess overall genetic variation in this important vector species. They will be used to search for population structure and migration patterns of C. pruni.     

Structural insight into how the human helicase subunit MCM2 may act as a histone chaperone together with ASF1 at the replication fork

MCM2 is a subunit of the replicative helicase machinery shown to interact with histones H3 and H4 during the replication process through its N-terminal domain. During replication, this interaction has been proposed to assist disassembly and assembly of nucleosomes on DNA. However, how this interaction participates in crosstalk with histone chaperones at the replication fork remains to be elucidated. Here, we solved the crystal structure of the ternary complex between the histone-binding domain of Mcm2 and the histones H3-H4 at 2.9 Å resolution. Histones H3 and H4 assemble as a tetramer in the crystal structure, but MCM2 interacts only with a single molecule of H3-H4. The latter interaction exploits binding surfaces that contact either DNA or H2B when H3-H4 dimers are incorporated in the nucleosome core particle. Upon binding of the ternary complex with the histone chaperone ASF1, the histone tetramer dissociates and both MCM2 and ASF1 interact simultaneously with the histones forming a 1:1:1:1 heteromeric complex. Thermodynamic analysis of the quaternary complex together with structural modeling support that ASF1 and MCM2 could form a chaperoning module for histones H3 and H4 protecting them from promiscuous interactions. This suggests an additional function for MCM2 outside its helicase function as a proper histone chaperone connected to the replication pathway.     

Fine-Scale Cartography of Human Impacts along French Mediterranean Coasts: A Relevant Map for the Management of Marine Ecosystems

Ecosystem services provided by oceans and seas support most human needs but are threatened by human activities. Despite existing maps illustrating human impacts on marine ecosystems, information remains either large-scale but rough and insufficient for stakeholders (1 km² grid, lack of data along the coast) or fine-scale but fragmentary and heterogeneous in methodology. The objectives of this study are to map and quantify the main pressures exerted on near-coast marine ecosystems, at a large spatial scale though in fine and relevant resolution for managers (one pixel = 20 x 20 m). It focuses on the French Mediterranean coast (1,700 km of coastline including Corsica) at a depth of 0 to 80 m. After completing and homogenizing data presently available under GIS on the bathymetry and anthropogenic pressures but also on the seabed nature and ecosystem vulnerability, we provide a fine modeling of the extent and impacts of 10 anthropogenic pressures on marine habitats. The considered pressures are man-made coastline, boat anchoring, aquaculture, urban effluents, industrial effluents, urbanization, agriculture, coastline erosion, coastal population and fishing. A 1:10 000 continuous habitat map is provided considering 11 habitat classes. The marine bottom is mostly covered by three habitats: infralittoral soft bottom, Posidonia oceanica meadows and circalittoral soft bottom. Around two thirds of the bottoms are found within medium and medium high cumulative impact categories. Seagrass meadows are the most impacted habitats. The most important pressures (in area and intensity) are urbanization, coastal population, coastal erosion and man-made coastline. We also identified areas in need of a special management interest. This work should contribute to prioritize environmental needs, as well as enhance the development of indicators for the assessment of the ecological status of coastal systems. It could also help better apply and coordinate management measures at a relevant scale for biodiversity conservation.     

Pituitary Stalk Interruption Syndrome from Infancy to Adulthood: Clinical,Hormonal, and Radiological Assessment According to the Initial Presentation

Background

Patients with pituitary stalk interruption syndrome (PSIS) are initially referred for hypoglycemia during the neonatal period or growth retardation during childhood. PSIS is either isolated (nonsyndromic) or associated with extra-pituitary malformations (syndromic).

Objective

To compare baseline characteristics and long-term evolution in patients with PSIS according to the initial presentation.

Study Design

Sixty-seven patients with PSIS were included. Data from subgroups were compared: neonates (n = 10) versus growth retardation patients (n = 47), and syndromic (n = 32) versus nonsyndromic patients (n = 35).

Results

Neonates displayed a more severe hormonal and radiological phenotype than children referred for growth retardation, with a higher incidence of multiple hormonal deficiencies (100% versus 34%; P = 0.0005) and a nonvisible anterior pituitary lobe (33% versus 2%; P = 0.0017). Regular follow-up of growth might have allowed earlier diagnosis in the children with growth retardation, as decreased growth velocity and growth retardation were present respectively 3 and 2 years before referral. We documented a progressive worsening of endocrine impairment throughout childhood in these patients. Presence of extra-pituitary malformations (found in 48%) was not associated with more severe hormonal and radiological characteristics. Growth under GH treatment was similar in the patient groups and did not vary according to the pituitary MRI findings.

Conclusions

PSIS diagnosed in the neonatal period has a particularly severe hormonal and radiological phenotype. The progressive worsening of endocrine impairment throughout childhood justifies periodic follow-up to check for additional hormonal deficiencies.