Highlights of science journals in December 2019

December 31, 2019 news / BIOON / -- December 2019 is coming to an end What are the highlights of science journals in December worth learning? Xiaobian has sorted this out and shared it with you 1 Science: challenge the routine! Part of the δ T cells bind to the bottom of MHC like molecules to identify the harmful cells doi: 10.1126/science.aav3900 In a new study, researchers from Monash University, Australian Research Council Center for advanced molecular imaging excellence and the Doherty Institute at the University of Melbourne redefined our understanding of T-cell recognition over the past 20 years The related research results were recently published in the journal Science, and the title of the paper is "a class of γ δ T cell receivers recognize the understanding of the anti retaining mobile MR1" Scanning electron micrograph of human T cells from the immune system of healthy donors The picture is from NIAID In order to interact with other cells in the body, T cells rely on specialized receptors called T cell receptors that recognize viral or bacterial fragments that bind to specific molecules called major histocompatibility complexes (MHCs) or MHC like molecules In the past 20 years, it has been widely accepted that T cell receptors bind to MHC and MHC like molecules for recognition In this new study, the researchers describe a cell population in a little-known group of T cells called delta T cells that recognize an MHC like molecule called MR1 By using high-intensity x-ray beams at the Australian synchrotron, they obtained detailed three-dimensional images of the interaction between the γ δ T cell receptor and MR1, and obtained interesting results: the γ δ T cell receptor binds under the MHC like molecule for recognition This highly unusual recognition mechanism reshapes our understanding of how T cell receptors interact with their target molecules and represents a major development in the field of T cell biology "We think of it as a sign of attachment to a cell," said Dr J é r? Me le nours, co-author of the paper at the Institute of biomedical discovery at Monash University We always thought T cells would come over and read this sign from above We have determined that some T cells can approach and interact with it from below These are important details that can change our future research methods of T cell biology It's important because T cells are a key weapon in our immune system, and understanding how they target and act on other cells is crucial to using their power to develop immunotherapies for diseases such as infection and cancer " 2 Science: transcriptome analysis of all protein coding genes in human blood cells in the whole genome range doi:10.1126/science.aax9198 in clinical and research environment, blood is the main source of molecular analysis of human beings, and is the target of many treatment strategies, which highlights the need for a comprehensive molecular map of the cells that make up human blood The human protein atlas project ( ORG) is an open database designed to map all human proteins by integrating a variety of genomic techniques, including antibody based imaging Previously, the human protein map included gene expression information from peripheral blood monocytes, but not from many other blood cell subsets In order to improve the resolution, people need to deeply characterize the cells in the blood to provide detailed details of gene expression in human blood cells and associate them with other tissues in the body For this reason, in a new study, researchers from Karolinska Institute and other research institutions in Sweden conducted transcriptome based expression analysis on 18 classical immune cell populations separated by flow cytometry They combined blood cell expression profiles with tissue expression profiles, including transcriptome data from external sources to expand the number of tissue types and brain regions included in this open database Based on the expression specificity and distribution in blood cells and tissues, they classified the whole genome of protein coding genes The relevant research results were recently published in the journal Science, and the title of the paper is "a genome wide transcription analysis of protein coding genes in human blood cells" These researchers provided the expression map of all protein coding genes in human blood cells and classified them according to the specificity and distribution of all protein coding genes in all major tissues and organs of the human body The whole genome analysis of RNA expression profile of blood cells can identify genes up-regulated in various immune cells, thus confirming previously known protein markers, and identifying new targets for further analysis There are 1448 protein coding genes expressed in a large number of single immune cell types It will be interesting to further study the corresponding proteins to explore the biological functions related to each cell phenotype 3 Science: host cells use aromatics receptors to detect bacterial quorum sensing signals doi: 10.1126/science.aaw1629 bacterial infection does not automatically lead to disease; many bacteria become dangerous only in large numbers In a new study, researchers from institutions such as the Max Planck Institute of infection biology in Germany found that host cells have a receptor that can't recognize the bacteria itself, but can detect communication between bacteria When there are a large number of bacteria, the host will use this receptor to record the pathogenic substances they secrete called virulence factors The related research results were recently published in the journal Science, and the title of the paper was "host monitoring of quorum sensing during Pseudomonas aeruginosa infection" Picture from science, 2019, DOI: 10.1126/science.aaw1629 Stefan Kaufmann of the Max Planck Institute of infectious biology and his team found that host cells can observe the communication between Pseudomonas aeruginosa by means of a receptor called the aryl hydrocarbon receptor The receptors detect quorum sensing molecules, allowing host cells to detect when the bacteria are ready to attack "Through this kind of spying behavior, host cells can activate the immune system when they need to resist this bacterial attack," explains Pedro Moura Alves, the first author of the paper In fact, before Pseudomonas aeruginosa reached their quorum sensing level, the receptor eavesdropped the conversation between the bacteria; the early stage of quorum sensing was detected to inhibit the aromatics receptor, thus blocking the early start of host immune defense "It works for the host because it saves energy and allows a small number of bacteria to exist alone, if they don't cause any damage," Kaufmann said Only when they reach a critical number can they have enough energy to defend " It also helps to prevent collateral damage caused by the immune system response 4 Science: challenge the routine! In a new study, under the leadership of David Bartel, Professor of biology, Sean mcgeary and Kathy Lin, a former graduate student of Whitehead biomedical research institute in the United States, researchers have collected a large number of data on six miRNAs An improved prediction model for all single miRNAs was developed Their findings provide unprecedented accuracy and granularity for miRNA target prediction The relevant research results were recently published in the journal Science, and the title of the paper was "the biological basis of microRNA targeting efficiency" In order to understand the targeting effect of miRNA, people need to identify specific sites that can bind to miRNA in miRNA sequence, and they also need to know the interaction intensity binding affinity on each site Generally, miRNA will bind to mRNA when at least six of the first eight nucleotides of miRNA match the complementary nucleotide sequence at a certain location of mRNA These two sequences are like rows of puzzle pieces pushed together: if each puzzle piece is inserted into the corresponding puzzle piece, then these rows of puzzle pieces can be combined into a locked puzzle -- miRNA can be combined with its target If the pieces can't be put together, the rows of pieces can't be connected together These binding sites are exactly matched with the first eight nucleotides of miRNA, which are called canonical sites In the past, it was thought that there was an obvious hierarchical relationship between them Regardless of the identity of miRNA, each site would produce a similar amount of inhibition However, mcgeary did not observe this Mcgeary studied six miRNAs and developed a method to measure the relative binding affinity of each miRNA to a large number of RNA sequences These measurements and mcgeary's further calculations from them form a new and rich database that can be used to improve miRNA targeting prediction Through these experiments, the researchers found that the expected target hierarchy of classical sites is not suitable for all miRNAs In fact, a single miRNA has a stronger affinity for a lower classical site in this desired hierarchy In addition, they found that each miRNA has a unique nonclassical binding site, some of which contain at least one base mismatch but can still bind miRNA They found that in many cases, although the pairing of nonclassical sites was imperfect or abnormal, the binding of miRNA to a nonclassical site was stronger than that to some classical sites "As humans, we like to classify things according to different characteristics," Lin said But to build a quantitative model, you have to realize that the interaction between each miRNA and the target is different " 5 A decade long scientific dispute is finally settled! Two science papers revealed that human annexin is a chromosomal multi subunit adenosine triphosphatase complex, which is composed of DOI: 10.1126/science.aaz3418, DOI: 10.1126/science.aaz4475 When loaded onto a chromosome, it produces a DNA loop to regulate the function of the chromosome It has been proposed that annexins can be assembled by ring extrusion, but there is no direct evidence to support this In the first new study, Jan Michael Peters, director of the Institute of molecular pathology (IMP), Vienna biological center, Austria, and his team confirmed for the first time that a molecular machine can actively and purposefully fold DNA through "loop extrusion", thus realizing a variety of important functions in interphase cells This new insight into the process of DNA looping has changed the old view about how genomes are assembled in cells This discovery clarifies the basic mechanism of life and solves a decade long scientific dispute The relevant research results were published in the Science Journal on December 13, 2019, with the title of "DNA loop extension by human cohesin" The picture is from Cees Dekker lab TU Delft / scixel The Peters team, including Iain Davidson, a senior postdoctoral researcher at the Peters lab, was able to reconstruct the function of adhesins in a simplified system in vitro So Davidson was able to see