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effector evolution

Xiaoyang Li, Haitao Tu, Shen Q Pan
Agrobacterium tumefaciens transfers oncogenic DNA (T-DNA) and effector proteins into various host plants. T-DNA is generated inside the bacteria and subsequently delivered into plant cells along with the companion effectors VirD2, VirE2, and VirE3. However, it is not clear how the T-complex consisting of VirD2 and VirE2 is assembled inside plant cells. Here, we report that the effector protein VirE3 localized to plant plasma membranes as an anchorage through a conserved α-helical-bundle domain. VirE3 interacted with itself and enabled VirE2 accumulation at host entry sites through direct interactions...
October 9, 2018: Cell Reports
Ashley Best, Yousef Abu Kwaik
Within the human host, Legionella pneumophila replicates within alveolar macrophages, leading to pneumonia. However, L. pneumophila is an aquatic generalist pathogen that replicates within a wide variety of protist hosts, including amoebozoa, percolozoa, and ciliophora. The intracellular lifestyles of L. pneumophila within the two evolutionarily distant hosts macrophages and protists are remarkably similar. Coevolution with numerous protist hosts has shaped plasticity of the genome of L. pneumophila , which harbors numerous proteins encoded by genes acquired from primitive eukaryotic hosts through interkingdom horizontal gene transfer...
October 9, 2018: MBio
Rodrigo Jiménez-Saiz, Sarita U Patil
While allergen immunotherapy (AIT) for IgE-mediated diseases holds curative potential, the considerable heterogeneity in clinical outcomes may relate to the complex mechanisms of tolerance. The regulation of humoral immunity by AIT contributes to the suppression of allergic responses. Recent findings have revealed novel roles for IgA and IgG antibodies in the induction of tolerance. These mechanisms synergize with their ability to block allergen-IgE binding and mediate inhibitory signaling of effector cells of the allergic response...
October 5, 2018: Current Allergy and Asthma Reports
Gaetan J A Thilliez, Miles R Armstrong, Tze-Yin Lim, Katie Baker, Agathe Jouet, Ben Ward, Cock van Oosterhout, Jonathan D G Jones, Edgar Huitema, Paul R J Birch, Ingo Hein
The oomycete pathogens Phytophthora infestans and P. capsici cause significant crop losses world-wide, threatening food security. In each case, pathogenicity factors, called RXLR effectors, contribute to virulence. Some RXLRs are perceived by resistance proteins to trigger host immunity, but our understanding of the demographic processes and adaptive evolution of pathogen virulence remains poor. Here, we describe PenSeq, a highly efficient enrichment sequencing approach for genes encoding pathogenicity determinants which, as shown for the infamous potato blight pathogen Phytophthora infestans, make up < 1% of the entire genome...
October 5, 2018: New Phytologist
Weiping Zhou, Bin Gao, Shunyi Zhu
Defensins are small, cysteine-rich, cationic antimicrobial peptides, serving as effectors of the innate immune system and modulators of the adaptive immune system. They extensively exist in multicellular organisms and are divided into cis and trans according to their disulfide bridge connectivity patterns. It has been proposed that these two types of defensins convergently originated from different ancestors. Here, we report the discovery of a structural signature involved in the formation of the cysteine-stabilized α-helix/β-sheet (CSαβ) fold of the cis-defensins in some trans-β-defensins, with only one amino acid indel (CXC vs...
October 2, 2018: Immunogenetics
Sarah Jacquelyn Smith, Mark Rebeiz, Lance Davidson
The development of anatomical structures is complex, beginning with patterning of gene expression by multiple gene regulatory networks (GRNs). These networks ultimately regulate the activity of effector molecules, which in turn alter cellular behavior during development. Together these processes biomechanically produce the three-dimensional shape that the anatomical structure adopts over time. However, the interfaces between these processes are often overlooked and also include counter-intuitive feedback mechanisms...
September 29, 2018: Current Opinion in Genetics & Development
Nick van Dijk, Samuel A Funt, Christian U Blank, Thomas Powles, Jonathan E Rosenberg, Michiel S van der Heijden
CONTEXT: The abysmal outlook of urothelial cancer (UC) has changed with the introduction of immunotherapy. Still, many patients do not respond and distinctive biomarkers are currently lacking. The rise of this novel armamentarium of immunotherapy treatments, in combination with the complex biology of an immunological tumor response, warrants the development of a comprehensive framework that can provide an overview of important immunological processes at play in individual patients. OBJECTIVE: To develop a comprehensive framework based on tumor- and host-specific parameters to understand immunotherapy response in UC...
September 28, 2018: European Urology
Tanvi Shashikant, Jian Ming Khor, Charles A Ettensohn
The skeletogenic gene regulatory network (GRN) of sea urchins and other echinoderms is one of the most intensively studied transcriptional networks in any developing organism. As such, it serves as a pre-eminent model of GRN architecture and evolution. This review summarizes our current understanding of this developmental network. We describe in detail the most comprehensive model of the skeletogenic GRN, one developed for the euechinoid sea urchin Strongylocentrotus purpuratus, including its initial deployment by maternal inputs, its elaboration and stabilization through regulatory gene interactions, and its control of downstream effector genes that directly drive skeletal morphogenesis...
September 27, 2018: Genesis: the Journal of Genetics and Development
Chunyu Liao, Rebecca A Slotkowski, Tatjana Achmedov, Chase L Beisel
The Class 2 Type V-A CRISPR effector protein Cas12a/Cpf1 has gained widespread attention in part because of the ease in achieving multiplexed genome editing, gene regulation, and DNA detection. Multiplexing derives from the ability of Cas12a alone to generate multiple guide RNAs from a transcribed CRISPR array encoding alternating conserved repeats and targeting spacers. While array design has focused on how to optimize guide-RNA sequences, little attention has been paid to sequences outside of the CRISPR array...
September 25, 2018: RNA Biology
Nicole Grandi, Enzo Tramontano
About 8% of our genome is composed of sequences with viral origin, namely human Endogenous Retroviruses (HERVs). HERVs are relics of ancient infections that affected the primates' germ line along the last 100 million of years, and became stable elements at the interface between self and foreign DNA. Intriguingly, HERV co-evolution with the host led to the domestication of activities previously devoted to the retrovirus life cycle, providing novel cellular functions. For example, selected HERV envelope proteins have been coopted for pregnancy-related purposes, and proviral Long Terminal Repeats participate in the transcriptional regulation of various cellular genes...
2018: Frontiers in Immunology
Jean-Luc Gallois, Benoît Moury, Sylvie German-Retana
In view of major economic problems caused by viruses, the development of genetically resistant crops is critical for breeders but remains limited by the evolution of resistance-breaking virus mutants. During the plant breeding process, the introgression of traits from Crop Wild Relatives results in a dramatic change of the genetic background that can alter the resistance efficiency or durability. Here, we conducted a meta-analysis on 19 Quantitative Trait Locus (QTL) studies of resistance to viruses in plants...
September 20, 2018: International Journal of Molecular Sciences
Simone Marcelletti, Marco Scortichini
A complementary taxonomic and population genetic study was performed to delineate genetically and ecologically distinct species within the Pseudomonas syringae complex by assessing 16 strains including pathovar strains that have converged to infect Prunus spp. trees, and two outgroups. Both average nucleotide identity and genome-to-genome distance comparison methods revealed the occurrence of distinct genomospecies, namely 1, 2, 3 and 8 (sensu Gardan et al.), with the latter two being closely related. Strains classified as P...
September 18, 2018: Archives of Microbiology
Hui Sun, Jana Kamanova, Maria Lara-Tejero, Jorge E Galán
Microbial infections are most often countered by inflammatory responses that are initiated through the recognition of conserved microbial products by innate immune receptors and result in pathogen expulsion1-6 . However, inflammation can also lead to pathology. Tissues such as the intestinal epithelium, which are exposed to microbial products, are therefore subject to stringent negative regulatory mechanisms to prevent signalling through innate immune receptors6-11 . This presents a challenge to the enteric pathogen Salmonella Typhimurium, which requires intestinal inflammation to compete against the resident microbiota and to acquire the nutrients and electron acceptors that sustain its replication12,13 ...
October 2018: Nature Microbiology
Ilia Belotserkovsky, Philippe J Sansonetti
Shigella and enteroinvasive Escherichia coli (EIEC) are gram-negative bacteria responsible for bacillary dysentery (shigellosis) in humans, which is characterized by invasion and inflammatory destruction of the human colonic epithelium. Different EIEC and Shigella subgroups rose independently from commensal E. coli through patho-adaptive evolution that included loss of functional genes interfering with the virulence and/or with the intracellular lifestyle of the bacteria, as well as acquisition of genetic elements harboring virulence genes...
September 15, 2018: Current Topics in Microbiology and Immunology
Robert A Syme, Kar-Chun Tan, Kasia Rybak, Timothy L Friesen, Bruce A McDonald, Richard P Oliver, James K Hane
We report a fungal pan-genome study involving Parastagonospora spp., including 21 isolates of the wheat (Triticum aestivum) pathogen Parastagonospora nodorum, 10 of the grass-infecting Parastagonospora avenae, and 2 of a closely related undefined sister species. We observed substantial variation in the distribution of polymorphisms across the pan-genome, including repeat-induced point mutations, diversifying selection and gene gains and losses. We also discovered chromosome-scale inter and intraspecific presence/absence variation of some sequences, suggesting the occurrence of one or more accessory chromosomes or regions that may play a role in host-pathogen interactions...
September 1, 2018: Genome Biology and Evolution
Migyeong Jo, Bora Hwang, Hyun Woung Yoon, Sang Taek Jung
Multimer formation is indispensable to the intrinsicbiologicalfunctions of many natural proteins. For example, the human immunoglobulin G (IgG) antibody has two variable regions (heavy chain variable domain [VH] and light chain variable domain [VL]) that must be assembled for specific antigen binding, and homodimerization of the antibody's Fc domain is essential for eliciting therapeutic effector functions. For the more efficient high-throughput directed evolution of multimeric proteins with ease of cultivation and handling, here we report a membrane protein drift and assembly (MPDA) system, in which a multimeric protein is displayed on a bacterial inner membrane by drifting and auto-assembling membrane-anchored subunit polypeptides...
September 1, 2018: Biotechnology and Bioengineering
Weiwei Rao, Xiaohong Zheng, Bingfang Liu, Qin Guo, Jianping Guo, Yan Wu, Xinxin Shangguan, Huiying Wang, Di Wu, Zhizheng Wang, Liang Hu, Chunxue Xu, Weihua Jiang, Jin Huang, Shaojie Shi, Guangcun He
The brown planthopper (BPH), Nilaparvata lugens (Stål), is a phloem sap-feeding insect. During the feeding on rice plant, BPH secretes salivary proteins with potential effector functions, which may play a critical role in the plant-insect interactions. However, a limited number of BPH effector proteins have been identified to date. Here, we sequenced the salivary gland transcriptomes of five BPH populations and subsequently established a N. lugens secretome consisting of 1140 protein-encoding genes. Secretome analysis revealed the presence of both conserved and rapidly evolving salivary proteins...
August 31, 2018: Molecular Plant-microbe Interactions: MPMI
Jianmin Zuo, Fiyaz Mohammed, Paul Moss
NKG2D is a major regulator of the activity of cytotoxic cells and interacts with eight different ligands (NKG2DL) from two families of MIC and ULBP proteins. The selective forces that drove evolution of NKG2DL are uncertain, but are likely to have been dominated by infectious disease and cancer. Of interest, NKG2DL are some of the most polymorphic genes outside the MHC locus and the study of these is uncovering a range of novel observations regarding the structure and function of NKG2DL. Polymorphism is present within all NKG2DL members and varies markedly within different populations...
2018: Frontiers in Immunology
Peter Thorpe, Carmen M Escudero-Martinez, Peter J A Cock, Sebastian Eves-van den Akker, Jorunn I B Bos
Aphids are a diverse group of taxa that contain agronomically important species, which vary in their host range and ability to infest crop plants. The genome evolution underlying agriculturally important aphid traits is not well understood. We generated draft genome assemblies for two aphid species: Myzus cerasi (black cherry aphid), and the cereal specialist Rhopalosiphum padi. Using a de novo gene prediction pipeline on both these, and three additional aphid genome assemblies (Acyrthosiphon pisum, D. noxia and M...
August 25, 2018: Genome Biology and Evolution
Ana Águeda-Pinto, Pedro José Esteves
The human S100A7 resides in the epidermal differentiation complex (EDC) and has been described as a key effector of innate immunity. In humans, there are five S100A7 genes located in tandem-S100A7A, S100A7P1, S100AL2, S100A7, and S100AP2. The presence of several retroelements in the S100A7A/S100A7P1 and S100A7/S100A7P2 clusters suggests that these genes were originated from a duplication around ~ 35 million years ago, during or after the divergence of Platyrrhini and Catarrhini primates. To test this hypothesis, and taking advantage of the high number of genomic sequences available in the public databases, we retrieved S100A7 gene sequences of 12 primates belonging to the Cercopithecoidea and Hominoidea (Catarrhini species)...
August 29, 2018: Immunogenetics
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