Mapping Neural Circuits with Activity-Dependent Nuclear Import of a Transcription Factor

Nuclear factor of activated T cells (NFAT) is a calcium-responsive transcription factor. We describe here an NFAT-based neural tracing method—CaLexA (calcium-dependent nuclear import of Lex A)—for labeling active neurons in behaving animals. In this system, sustained neural activity induces nuclear import of the chimeric transcription factor LexA-VP16-NFAT, which in turn drives green fluorescent protein (GFP) reporter expression only in active neurons. We tested this system in Drosophila and found that volatile sex pheromones excite specific neurons in the olfactory circuit. Furthermore, complex courtship behavior associated with multi-modal sensory inputs activated neurons in the ventral nerve cord. This method harnessing the mechanism of activity-dependent nuclear import of a transcription factor can be used to identify active neurons in specific neuronal population in behaving animals

Transient Reversal of Episome Silencing Precedes VP16-Dependent Transcription during Reactivation of Latent HSV-1 in Neurons

Herpes simplex virus type-1 (HSV-1) establishes latency in peripheral neurons, creating a permanent source of recurrent infections. The latent genome is assembled into chromatin and lytic cycle genes are silenced. Processes that orchestrate reentry into productive replication (reactivation) remain poorly understood. We have used latently infected cultures of primary superior cervical ganglion (SCG) sympathetic neurons to profile viral gene expression following a defined reactivation stimulus. Lytic genes are transcribed in two distinct phases, differing in their reliance on protein synthesis, viral DNA replication and the essential initiator protein VP16. The first phase does not require viral proteins and has the appearance of a transient, widespread de-repression of the previously silent lytic genes. This allows synthesis of viral regulatory proteins including VP16, which accumulate in the cytoplasm of the host neuron. During the second phase, VP16 and its cellular cofactor HCF-1, which is also predominantly cytoplasmic, concentrate in the nucleus where they assemble an activator complex on viral promoters. The transactivation function supplied by VP16 promotes increased viral lytic gene transcription leading to the onset of genome amplification and the production of infectious viral particles. Thus regulated localization of de novo synthesized VP16 is likely to be a critical determinant of HSV-1 reactivation in sympathetic neurons

Pathogenic Huntingtin Repeat Expansions in Patients with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.

We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40-64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington's disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered

Family Resources in Two Generations and School Readiness Among Children of Teen Parents

Overall, children born to teen parents experience disadvantaged cognitive achievement at school entry compared with children born to older parents. However, within this population, there is variation, with a significant fraction of teen parents’ children acquiring adequate preparation for school entry during early childhood. We ask whether the family background of teen parents explains this variation. We use data on children born to teen mothers from three waves of the Early Childhood Longitudinal Study-Birth Cohort (N ~ 700) to study the association of family background with children’s standardized reading and mathematics achievement scores at kindergarten entry. When neither maternal grandparent has completed high school, children’s scores on standardized assessments of math and reading achievement are one-quarter to one-third of a standard deviation lower compared with families where at least one grandparent finished high school. This association is net of teen mothers’ own socioeconomic status in the year prior to children’s school entry

Matrix-assisted laser desorption ionization--time of flight mass spectrometry: an emerging tool for the rapid identification of mosquito vectors.

BACKGROUND: The identification of mosquito vectors is typically based on morphological characteristics using morphological keys of determination, which requires entomological expertise and training. The use of protein profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), which is increasingly being used for the routine identification of bacteria, has recently emerged for arthropod identification. METHODS: To investigate the usefulness of MALDI-TOF-MS as a mosquito identification tool, we tested protein extracts made from mosquito legs to create a database of reference spectra. The database included a total of 129 laboratory-reared and field-caught mosquito specimens consisting of 20 species, including 4 Aedes spp., 9 Anopheles spp., 4 Culex spp., Lutzia tigripes, Orthopodomyia reunionensis and Mansonia uniformis. For the validation study, blind tests were performed with 76 specimens consisting of 1 to 4 individuals per species. A cluster analysis was carried out using the MALDI-Biotyper and some spectra from all mosquito species tested. RESULTS: Biomarker mass sets containing 22 and 43 masses have been detected from 100 specimens of the Anopheles, Aedes and Culex species. By carrying out 3 blind tests, we achieved the identification of mosquito vectors at the species level, including the differentiation of An. gambiae complex, which is possible using MALDI-TOF-MS with 1.8 as the cut-off identification score. A cluster analysis performed with all available mosquito species showed that MALDI-Biotyper can distinguish between specimens at the subspecies level, as demonstrated for An gambiae M and S, but this method cannot yet be considered a reliable tool for the phylogenetic study of mosquito species. CONCLUSIONS: We confirmed that even without any specific expertise, MALDI-TOF-MS profiling of mosquito leg protein extracts can be used for the rapid identification of mosquito vectors. Therefore, MALDI-TOF-MS is an alternative, efficient and inexpensive tool that can accurately identify mosquitoes collected in the field during entomological surveys

Loss of HCF-1–Chromatin Association Precedes Temperature-Induced Growth Arrest of tsBN67 Cells

Human HCF-1 is a large, highly conserved, and abundant nuclear protein that plays an important but unknown role in cell proliferation. It also plays a role in activation of herpes simplex virus immediate-early gene transcription by the viral regulatory protein VP16. A single proline-to-serine substitution in the HCF-1 VP16 interaction domain causes a temperature-induced arrest of cell proliferation in hamster tsBN67 cells and prevents transcriptional activation by VP16. We show here that HCF-1 is naturally bound to chromatin in uninfected cells through its VP16 interaction domain. HCF-1 is chromatin bound in tsBN67 cells at permissive temperature but dissociates from chromatin before tsBN67 cells stop proliferating at the nonpermissive temperature, suggesting that loss of HCF-1 chromatin association is the primary cause of the temperature-induced tsBN67 cell proliferation arrest. We propose that the role of HCF-1 in cell proliferation is to regulate gene transcription by associating with a multiplicity of DNA-bound transcription factors through its VP16 interaction domain

Green Microwave Synthesis of MIL-100(Al, Cr, Fe) Nanoparticles for Thin-Film Elaboration

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The novel coactivator C1 (HCF) coordinates multiprotein enhancer formation and mediates transcription activation by GABP

Transcription of the herpes simplex virus 1 (HSV–1) immediate early (IE) genes is determined by multiprotein enhancer complexes. The core enhancer assembly requires the interactions of the POU-homeodomain protein Oct–1, the viral transactivator αTIF and the cellular factor C1 (HCF). In this context, the C1 factor interacts with each protein to assemble the stable enhancer complex. In addition, the IE enhancer cores contain adjacent binding sites for other cellular transcription factors such as Sp1 and GA-binding protein (GABP). In this study, a direct interaction of the C1 factor with GABP is demonstrated, defining the C1 factor as the critical coordinator of the enhancer complex assembly. In addition, mutations that reduce the GABP transactivation potential also impair the C1–GABP interaction, indicating that the C1 factor functions as a novel coactivator of GABP-mediated transcription. The interaction and coordinated assembly of the enhancer proteins by the C1 factor may be critical for the regulation of the HSV lytic–latent cycle