Cell biological mechanisms of activity-dependent synapse to nucleus translocation of CRTC1 in neurons.

Previous studies have revealed a critical role for CREB-regulated transcriptional coactivator (CRTC1) in regulating neuronal gene expression during learning and memory. CRTC1 localizes to synapses but undergoes activity-dependent nuclear translocation to regulate the transcription of CREB target genes. Here we investigate the long-distance retrograde transport of CRTC1 in hippocampal neurons. We show that local elevations in calcium, triggered by activation of glutamate receptors and L-type voltage-gated calcium channels, initiate active, dynein-mediated retrograde transport of CRTC1 along microtubules. We identify a nuclear localization signal within CRTC1, and characterize three conserved serine residues whose dephosphorylation is required for nuclear import. Domain analysis reveals that the amino-terminal third of CRTC1 contains all of the signals required for regulated nucleocytoplasmic trafficking. We fuse this region to Dendra2 to generate a reporter construct and perform live-cell imaging coupled with local uncaging of glutamate and photoconversion to characterize the dynamics of stimulus-induced retrograde transport and nuclear accumulation

A directed search for gravitational waves from Scorpius X-1 with initial LIGO

19 pages, 8 figuresInternational audienceWe present results of a search for continuously-emitted gravitational radiation, directed at the brightest low-mass X-ray binary, Scorpius X-1. Our semi-coherent analysis covers 10 days of LIGO S5 data ranging from 50-550 Hz, and performs an incoherent sum of coherent $\mathcal{F}$-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of 1.3e-24 and 8e-25 are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof of principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of ~1.4 for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector

Regulation and transcriptional role of CRTC1 during activity in neurons

Long term memory is mediated by long-lasting forms of synaptic plasticity that require new gene transcription for their persistence. Previous work has shown that neuronal CREB-regulated transcriptional coactivator 1 (CRTC1) plays a crucial role during learning and memory by regulating activity-dependent gene expression. We have shown that CRTC1 undergoes synapse-to-nucleus translocation to regulate transcription of CREB target genes in response to neuronal activity. In this thesis, we investigate the regulation and retrograde transport of CRTC1 in neurons and examine the nuclear role of CRTC1 in activity-dependent gene transcription. Our first goal was to identify the mechanisms by which CRTC1 responds to activity. We describe key synaptic processes necessary to trigger dephosphorylation of three serine residues that are required for dynein-mediated transport of CRTC1 to the nucleus. Our second goal was to understand the role of CRCT1 as a transcriptional coactivator. We use a combination of ChIP-seq, ATAC-seq and RNA-seq to understand how CRTC1 binding to CREB and other transcription factors correlates with changes in chromatin accessibility and transcription of activity-induced genes. Finally, we summarize a series of projects that attempt to elucidate how regulation of CRTC1’s phosphorylation code may influence its function in neurons. These studies highlight the complexities of CRTC1 as an intrinsically disordered protein with 50 phosphorylated residues and a variety of potential interacting partners

Cell biological mechanisms of activity-dependent synapse to nucleus translocation of CRTC1 in neurons.

Previous studies have revealed a critical role for CREB-regulated transcriptional coactivator (CRTC1) in regulating neuronal gene expression during learning and memory. CRTC1 localizes to synapses but undergoes activity-dependent nuclear translocation to regulate the transcription of CREB target genes. Here we investigate the long-distance retrograde transport of CRTC1 in hippocampal neurons. We show that local elevations in calcium, triggered by activation of glutamate receptors and L-type voltage-gated calcium channels, initiate active, dynein-mediated retrograde transport of CRTC1 along microtubules. We identify a nuclear localization signal within CRTC1, and characterize three conserved serine residues whose dephosphorylation is required for nuclear import. Domain analysis reveals that the amino-terminal third of CRTC1 contains all of the signals required for regulated nucleocytoplasmic trafficking. We fuse this region to Dendra2 to generate a reporter construct and perform live-cell imaging coupled with local uncaging of glutamate and photoconversion to characterize the dynamics of stimulus-induced retrograde transport and nuclear accumulation

Italian Guidelines in patch testing - Adapted from the European Society of Contact Dermatitis (ESCD)

Patch testing is the standard procedure used to diagnose allergic contact dermatitis. It is an in-vivo test, which reproduces the reaction to a contact allergen. This in-vivo test aims to reproduce the elicitation phase of allergic contact dermatitis and is performed applying allergens under occlusion on the skin under standardized conditions. These guidelines for the best practice in performing patch test have been developed by an Italian group of experts taking in account the Italian legislation and local pharmacological governance. Guidelines are adapted from the original article under the guidance of the European Society of Contact Dermatitis (ESCD) and on the basis of the SIDAPA guidelines

Search for intermediate mass black hole binaries in the first observing run of Advanced LIGO

International audienceDuring their first observational run, the two Advanced LIGO detectors attained an unprecedented sensitivity, resulting in the first direct detections of gravitational-wave signals produced by stellar-mass binary black hole systems. This paper reports on an all-sky search for gravitational waves (GWs) from merging intermediate mass black hole binaries (IMBHBs). The combined results from two independent search techniques were used in this study: the first employs a matched-filter algorithm that uses a bank of filters covering the GW signal parameter space, while the second is a generic search for GW transients (bursts). No GWs from IMBHBs were detected; therefore, we constrain the rate of several classes of IMBHB mergers. The most stringent limit is obtained for black holes of individual mass 100  M⊙, with spins aligned with the binary orbital angular momentum. For such systems, the merger rate is constrained to be less than 0.93  Gpc−3 yr−1 in comoving units at the 90% confidence level, an improvement of nearly 2 orders of magnitude over previous upper limits