Structural determinants of the SINE B2 element embedded in the long non-coding RNA activator of translation AS Uchl1

Pervasive transcription of mammalian genomes leads to a previously underestimated level of complexity in gene regulatory networks. Recently, we have identified a new functional class of natural and synthetic antisense long non-coding RNAs (lncRNA) that increases translation of partially overlapping sense mRNAs. These molecules were named SINEUPs, as they require an embedded inverted SINE B2 element for their UP-regulation of translation. Mouse AS Uchl1 is the representative member of natural SINEUPs. It was originally discovered for its role in increasing translation of Uchl1 mRNA, a gene associated with neurodegenerative diseases. Here we present the secondary structure of the SINE B2 Transposable Element (TE) embedded in AS Uchl1. We find that specific structural regions, containing a short hairpin, are required for the ability of AS Uchl1 RNA to increase translation of its target mRNA. We also provide a high-resolution structure of the relevant hairpin, based on NMR observables. Our results highlight the importance of structural determinants in embedded TEs for their activity as functional domains in lncRNAs

Single cell expression analysis of primate-specific retroviruses-derived HPAT lincRNAs in viable human blastocysts identifies embryonic cells co-expressing genetic markers of multiple lineages

Chromosome instability and aneuploidies occur very frequently in human embryos, impairing proper embryogenesis and leading to cell cycle arrest, loss of cell viability, and developmental failures in 50–80% of cleavage-stage embryos. This high frequency of cellular extinction events represents a significant experimental obstacle challenging analyses of individual cells isolated from human preimplantation embryos. We carried out single cell expression profiling of 241 individual cells recovered from 32 human embryos during the early and late stages of viable human blastocyst (VHB) differentiation. Classification of embryonic cells was performed solely based on expression patterns of human pluripotency-associated transcripts (HPAT), which represent a family of primate-specific transposable element-derived lincRNAs highly expressed in human embryonic stem cells and regulating nuclear reprogramming and pluripotency induction. We then validated our findings by analyzing transcriptomes of 1,708 individual cells recovered from more than 100 human embryos and 259 mouse cells from more than 40 mouse embryos at different stages of preimplantation embryogenesis. HPAT's expression-guided spatiotemporal reconstruction of human embryonic development inferred from single-cell expression analysis of VHB differentiation enabled identification of telomerase-positive embryonic cells co-expressing key pluripotency regulatory genes and genetic markers of three major lineages. Follow-up validation analyses confirmed the emergence in human embryos prior to lineage segregation of telomerase-positive cells co-expressing genetic markers of multiple lineages. Observations reported in this contribution support the hypothesis of a developmental pathway of creation embryonic lineages and extraembryonic tissues from telomerase-positive pre-lineage cells manifesting multi-lineage precursor phenotype

Photoluminescence characteristics of soft PZT 53/47 ceramic doped at A and/or B sites

Abstract This study presents the photoluminescence characteristics of the PZT 53/47 system doped at A and/or B sites, with Nb (PZTN), La (PLZT), and Nb–La (PLZTN) in the concentration range from 0.2 to 1.0 molar fraction. The intensity of the emission bands of the system PZTN is two orders higher than the intensity of the emission bands of the systems PLZT and PLZTN, and these emission bands are located at 1.73 eV (718 nm), 2.56 eV (485 nm), and 2.93 eV (424 nm). The origin of the luminescence in these systems is associated with lead and oxygen vacancies produced during the sintering process. The results from X-ray diffraction (XRD) show a mixture of rhombohedral and tetragonal phases. The system PZTN shows a higher tetragonal phase concentration, while PLZT and PLZTN systems show a higher rhombohedral phase concentration. The cell volume shows an increase with dopant concentration only in the case of the PLZTN system. The band gap energy shows a small variation in the PZTN and PLZTN cases around 3.0 eV, a close value to the band gap energy of the pure PZT 53/47 sample. The system PLZT shows an increasing behavior until 4.41 eV for the higher dopant concentration

Microestructural and ferroelectric analyses of Pb₁₋₃ₓ/₂Laₓ(Zr₀.₅₄Ti₀.₄₆)₁₋₅ᵧ/₄NbᵧO₃ soft ceramics.

Microstructural and ferroelectric analyses were carried out on Pb₁₋₃ₓ/₂Laₓ(Zr₀.₅₄Ti₀.₄₆)₁₋₅ᵧ/₄NbᵧO₃ ceramics, x = y = 0.004, 0.006, 0.008 and 0.01 mol%. Using Piezoresponse Force Microscopy (PFM) and piezoelectric Hysteresis Loop (HL), ferroelectric behavior, and ferroelectric domain sizes were determined. Grain size (as determinate by SEM) and ferroelectric domain area decrease with the increase of dopant concentration from 3 μm to 1 μm and from 0.56 μm² to 0.32 μm², respectively. The maximum remnant polarization was obtained for Pb₀.₉₈₅La₀.₀₁Zr₀.₅₄Ti₀.₄₆)₀.₉₈₇₅Nb₀.₀₁O₃, showing that samples polarize easier with higher La³⁺ and Nb⁵⁺ dopant concentration. The coercive field does not show significant differences as the La and Nb content is varied. Grains tend to be single crystals as the La³⁺ and Nb⁵⁺ dopant concentration is increased.Análisis microestructural y ferroeléctrico de cerámicas suaves de Pb₁₋₃ₓ/₂Laₓ(Zr₀.₅₄Ti₀.₄₆)₁₋₅ᵧ/₄NbᵧO₃ Se realizaron análisis microestructurales y ferroeléctricos en cerámicas de Pb₁₋₃ₓ/₂Laₓ(Zr₀.₅₄Ti₀.₄₆)₁₋₅ᵧ/₄NbᵧO₃, x = y = 0.004, 0.006, 0.008 y 0.01% en moles. Se utilizó microscopía de fuerza de respuesta piezoeléctrica (PFM) y lazo de histéresis piezoeléctrica (HL), se determinó el comportamiento ferroeléctrico y el tamaño de dominio ferroeléctrico. El tamaño de grano (determinado por SEM) y el área del dominio ferroeléctrico disminuyen con el aumento de la concentración del dopante de 3 μm a 1 μm y de 0,56 μm² a 0,32 μm², respectivamente. La máxima polarización remanente se obtuvo para Pb₀.₉₈₅La₀.₀₁Zr₀.₅₄Ti₀.₄₆)₀.₉₈₇₅Nb₀.₀₁O₃, lo que demuestra que las muestras se polarizan más fácilmente con una mayor concentración de dopante La³⁺ y Nb⁵⁺. El campo coercitivo no presenta diferencias significativas ya que el contenido de La y Nb es variado. Los granos tienden a ser monocristales a medida que aumenta la concentración de los dopantes La3 + Nb5+