Investigating cellular recognition using crispr/cas9 genetic screening.

Neighbouring cells can recognise and communicate with each other by direct binding between cell surface receptor and ligand pairs. Examples of cellular recognition events include pathogen entry into a host cell, sperm-egg fusion, and self/nonself discrimination by the immune system. Despite growing appreciation of cell surface recognition molecules as potential therapeutic targets, identifying key factors contributing to cellular recognition remains technically challenging to perform on a genome-wide scale. Recently, genome-scale clustered regularly interspaced short palindromic repeats (CRISPR) knockout or activation (CRISPR-KO/CRISPRa) screens have been applied to identify the molecular determinants of cellular recognition. In this review, we discuss how CRISPR-KO/CRISPRa screening has contributed to our understanding of cellular recognition processes, and how it can be applied to investigate these important interactions in a range of biological contexts. Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved

Structure of KAP1 tripartite motif identifies molecular interfaces required for retroelement silencing.

Transcription of transposable elements is tightly regulated to prevent genome damage. KRAB domain-containing zinc finger proteins (KRAB-ZFPs) and KRAB-associated protein 1 (KAP1/TRIM28) play a key role in regulating retrotransposons. KRAB-ZFPs recognize specific retrotransposon sequences and recruit KAP1, inducing the assembly of an epigenetic silencing complex, with chromatin remodeling activities that repress transcription of the targeted retrotransposon and adjacent genes. Our biophysical and structural data show that the tripartite motif (TRIM) of KAP1 forms antiparallel dimers, which further assemble into tetramers and higher-order oligomers in a concentration-dependent manner. Structure-based mutations in the B-box 1 domain prevent higher-order oligomerization without significant loss of retrotransposon silencing activity, indicating that, in contrast to other TRIM-family proteins, self-assembly is not essential for KAP1 function. The crystal structure of the KAP1 TRIM dimer identifies the KRAB domain binding site in the coiled-coil domain near the dyad. Mutations at this site abolished KRAB binding and transcriptional silencing activity of KAP1. This work identifies the interaction interfaces in the KAP1 TRIM responsible for self-association and KRAB binding and establishes their role in retrotransposon silencing.This work was supported by Wellcome Trust through Senior Research Fellowship 101908/Z/13/Z and PhD Studentship 205833/Z/16/Z

Examining the interrelationship among critical success factors of public private partnership infrastructure projects

Examining the interrelationships among critical success factors (CSFs) for public private partnership (PPP) projects is of importance for improving PPP project performance and maintaining the sustainability of PPP project implementation. Previous studies mostly focused on the identification of the CSFs for PPP projects; limited studies investigated the interrelationships among CSFs. Hence, the research objectives are (a) to determine the interrelationships among CSFs of PPP projects taking into account the public and (b) to identify influence paths contributing to take advantage of CSFs in the process of PPP implementation. A literature review and expert interviews were adopted to construct the CSFs framework; nine hypotheses were constructed and tested by the structural equation modelling (SEM) based on the data collected from a questionnaire survey. This research reveals that the relationship between public and private partners is the leader-follower relationship, not the partnership relationship, in PPP projects, indicating that the responsibilities, power or resources existing among partners are very unequal. It also highlights that public involvement has a negative effect on the process of service provisions, and costs and risks exist in the process of public involvement in PPP projects. The determined interrelationships among CSFs will contribute to the sustainability and success of a PPP project

Host structural stabilization of Li1.232Mn0.615Ni0.154O2 through K-doping attempt: toward superior electrochemical performances

Lithium-rich layered cathodes are known famously for its superior capacity over traditional layered oxides but trapped for lower initial coulombic efficiency, poorer rate capability and worse cyclic stability in spite of diverse attempts. Herein, a new K-stabilized Li-rich layered cathode synthesized through a simple oxalate co-precipitation is reported for its super electrochemical performances. Compared with pristine Li-rich layered cathode, K-stabilized one reaches a higher initial coulombic efficiency of 87% from 76% and outruns for 94% of capacity retention and 244 mAh g-1 of discharge capacity at 0.5C after 100 cycles. Moreover, 133 mAh g-1 of discharge capacity can be delivered even charged at 10C showing a highly-improved rate capability. X-ray diffraction and electrochemical impedance spectroscopy tests show that enlarged Li slab layer caused by K+ accommodation can provide facile Li+ diffusion paths and facilitate Li+ migration from the crystal lattice. As a consequence, the introduction of K+ in the host layered structure can inhibit the detrimental spinel structure growth during cycling. Therefore, the K-stabilized Li-rich layered materials can be considered to be an attractive alternative to meet with the higher power and energy density demands of advanced lithium-ion battery

Transgenic Expression of P1A Induced Thymic Tumor: A Role for Onco-Fetal Antigens in Tumorigenesis

P1A is the first known tumor rejection antigen. It is expressed in embryonic stem cells and multiple tumors but is silent in adult tissues except for the testis and placenta. Therefore, P1A represents a prototype for onco-fetal antigens. To test the potential function of P1A in tumorigenesis, we used a transgenic mouse expressing P1A in lymphoid cells. We observed that immunodeficient host P1A transgenic mice developed thymic tumors after 7 months of age and had shorter survival rates compared to control groups. Most of the 7 examined tumors displayed B cell lineage markers. The P1A transgenic bone marrow cells had higher proliferation ability and more potential progenitors compared to control bone marrow cells. To our knowledge, our data provided the first example that onco-fetal antigen can promote tumorigenesis

New provincial CO2 emission inventories in China based on apparent energy consumption data and updated emission factors

This study employs “apparent energy consumption” approach and updated emissions factors to re-calculate Chinese provincial CO2 emissions during 2000–2012 to reduce the uncertainty in Chinese CO2 emission estimates for the first time. The study presents the changing emission-socioeconomic features of each provinces as well. The results indicate that Chinese provincial aggregated CO2 emissions calculated by the apparent energy consumption and updated emissions factors are coincident with the national emissions estimated by the same approach, which are 12.69% smaller than the one calculated by the traditional approach and IPCC default emission factors. The provincial aggregated CO2 emissions increased from 3160 million tonnes in 2000 to 8583 million tonnes in 2012. During the period, Shandong province contributed most to national emissions accumulatively (with an average percentage of 10.35%), followed by Liaoning (6.69%), Hebei (6.69%) and Shanxi provinces (6.25%). Most of the CO2 emissions were from raw coal, which is primarily burned in the thermal power sector. The analyses of per capita emissions and emission intensity in 2012 indicates that provinces located in the northwest and north had higher per capita CO2 emissions and emission intensities than the central and southeast coastal regions. Understanding the emissions and emission-socioeconomic characteristics of different provinces is critical for developing mitigation strategies

Pooled extracellular receptor-ligand interaction screening using CRISPR activation.

Extracellular interactions between cell surface receptors are necessary for signaling and adhesion but identifying them remains technically challenging. We describe a cell-based genome-wide approach employing CRISPR activation to identify receptors for a defined ligand. We show receptors for high-affinity antibodies and low-affinity ligands can be unambiguously identified when used in pools or as individual binding probes. We apply this technique to identify ligands for the adhesion G-protein-coupled receptors and show that the Nogo myelin-associated inhibitory proteins are ligands for ADGRB1. This method will enable extracellular receptor-ligand identification on a genome-wide scale