scholarly journals Systematic CRISPR-Cas9-Mediated Modifications of Plasmodium yoelii ApiAP2 Genes Reveal Functional Insights into Parasite Development

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Cui Zhang ◽  
Zhenkui Li ◽  
Huiting Cui ◽  
Yuanyuan Jiang ◽  
Zhenke Yang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Protein Expression ◽  
Gene Family ◽  
Developmental Stages ◽  
Critical Role ◽  
Plasmodium Yoelii ◽  
Complex Life Cycle ◽  
Parasite Development ◽  
Malaria Parasites ◽  
Functional Roles

ABSTRACT Malaria parasites have a complex life cycle with multiple developmental stages in mosquito and vertebrate hosts, and different developmental stages express unique sets of genes. Unexpectedly, many transcription factors (TFs) commonly found in eukaryotic organisms are absent in malaria parasites; instead, a family of genes encoding proteins similar to the plant Apetala2 (ApiAP2) transcription factors is expanded in the parasites. Several malaria ApiAP2 genes have been shown to play a critical role in parasite development; however, the functions of the majority of the ApiAP2 genes remain to be elucidated. In particular, no study on the Plasmodium yoelii ApiAP2 (PyApiAP2) gene family has been reported so far. This study systematically investigated the functional roles of PyApiAP2 genes in parasite development. Twenty-four of the 26 PyApiAP2 genes were selected for disruption, and 12 were successfully knocked out using the clustered regularly interspaced short palindromic repeat–CRISPR-associated protein 9 (CRISPR-Cas9) method. The effects of gene knockout (KO) on parasite development in mouse and mosquito stages were evaluated. Ten of 12 successfully disrupted genes, including two genes that have not been functionally characterized in any Plasmodium species previously, were shown to be critical for P. yoelii development of sexual and mosquito stages. Additionally, seven of the genes were labeled for protein expression analysis, revealing important information supporting their functions. This study represents the first systematic functional characterization of the P. yoelii ApiAP2 gene family and discovers important insights on the roles of the ApiAP2 genes in parasite development. IMPORTANCE Malaria is a parasitic disease that infects hundreds of millions of people, leading to an estimated 0.35 million deaths in 2015. A better understanding of the mechanism of gene expression regulation during parasite development may provide important clues for disease control and prevention. In this study, systematic gene disruption experiments were performed to study the functional roles of members of the Plasmodium yoelii ApiAP2 (PyApiAP2) gene family in parasite development. Genes that are critical for the development of male and female gametocytes, oocysts, and sporozoites were characterized. The protein expression profiles for seven of the PyApiAP2 gene products were also analyzed, revealing important information on their functions. This study provides expression and functional information for many PyApiAP2 genes, which can be explored for disease management.

scholarly journals Regulation of Plasmodium yoelii Oocyst Development by Strain- and Stage-Specific Small-Subunit rRNA

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Yanwei Qi ◽  
Feng Zhu ◽  
Richard T. Eastman ◽  
Young Fu ◽  
Martine Zilversmit ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Small Subunit ◽  
Plasmodium Yoelii ◽  
Rrna Genes ◽  
Parasite Development ◽  
Rrna Gene ◽  
Small Subunit Rrna ◽  
Malaria Parasites ◽  
Content Type ◽  
Small Subunit Rrna Gene

ABSTRACT One unique feature of malaria parasites is the differential transcription of structurally distinct rRNA (rRNA) genes at different developmental stages: the A-type genes are transcribed mainly in asexual stages, whereas the S-type genes are expressed mostly in sexual or mosquito stages. Conclusive functional evidence of different rRNAs in regulating stage-specific parasite development, however, is still absent. Here we performed genetic crosses of Plasmodium yoelii parasites with one parent having an oocyst development defect (ODD) phenotype and another producing normal oocysts to identify the gene(s) contributing to the ODD. The parent with ODD—characterized as having small oocysts and lacking infective sporozoites—was obtained after introduction of a plasmid with a green fluorescent protein gene into the parasite genome and subsequent passages in mice. Quantitative trait locus analysis of genome-wide microsatellite genotypes of 48 progeny from the crosses linked an ~200-kb segment on chromosome 6 containing one of the S-type genes (D-type small subunit rRNA gene [D-ssu]) to the ODD. Fine mapping of the plasmid integration site, gene expression pattern, and gene knockout experiments demonstrated that disruption of the D-ssu gene caused the ODD phenotype. Interestingly, introduction of the D-ssu gene into the same parasite strain (self), but not into a different subspecies, significantly affected or completely ablated oocyst development, suggesting a stage- and subspecies (strain)-specific regulation of oocyst development by D-ssu. This study demonstrates that P. yoelii D-ssu is essential for normal oocyst and sporozoite development and that variation in the D-ssu sequence can have dramatic effects on parasite development. IMPORTANCE Malaria parasites are the only known organisms that express structurally distinct rRNA genes at different developmental stages. The differential expression of these genes suggests that they play unique roles during the complex life cycle of the parasites. Conclusive functional proof of different rRNAs in regulating parasite development, however, is still absent or controversial. Here we functionally demonstrate for the first time that a stage-specifically expressed D-type small-subunit rRNA gene (D-ssu) is essential for oocyst development of the malaria parasite Plasmodium yoelii in the mosquito. This study also shows that variations in D-ssu sequence and/or the timing of transcription may have profound effects on parasite oocyst development. The results show that in addition to protein translation, rRNAs of malaria parasites also regulate parasite development and differentiation in a strain-specific manner, which can be explored for controlling parasite transmission.

scholarly journals What functional genomics has taught us about transcriptional regulation in malaria parasites

2019 ◽  
Vol 18 (5) ◽  
pp. 290-301 ◽  
Author(s):  
Christa G Toenhake ◽  
Richárd Bártfai
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Life Cycle ◽  
Functional Genomics ◽  
Expression Patterns ◽  
Regulatory Elements ◽  
Complex Life Cycle ◽  
Malaria Parasites ◽  
Gene Regulatory

Abstract Malaria parasites are characterized by a complex life cycle that is accompanied by dynamic gene expression patterns. The factors and mechanisms that regulate gene expression in these parasites have been searched for even before the advent of next generation sequencing technologies. Functional genomics approaches have substantially boosted this area of research and have yielded significant insights into the interplay between epigenetic, transcriptional and post-transcriptional mechanisms. Recently, considerable progress has been made in identifying sequence-specific transcription factors and DNA-encoded regulatory elements. Here, we review the insights obtained from these efforts including the characterization of core promoters, the involvement of sequence-specific transcription factors in life cycle progression and the mapping of gene regulatory elements. Furthermore, we discuss recent developments in the field of functional genomics and how they might contribute to further characterization of this complex gene regulatory network.

scholarly journals Effector CD8+ T Lymphocytes against Liver Stages of Plasmodium yoelii Do Not Require Gamma Interferon for Antiparasite Activity

2008 ◽  
Vol 76 (8) ◽  
pp. 3628-3631 ◽  
Author(s):  
Sumana Chakravarty ◽  
G. Christian Baldeviano ◽  
Michael G. Overstreet ◽  
Fidel Zavala
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protective Immunity ◽  
Critical Role ◽  
Plasmodium Yoelii ◽  
Gamma Interferon ◽  
Parasite Development ◽  
Wild Type ◽  
Ifn Γ

ABSTRACT The protective immune response against liver stages of the malaria parasite critically requires CD8+ T cells. Although the nature of the effector mechanism utilized by these cells to repress parasite development remains unclear, a critical role for gamma interferon (IFN-γ) has been widely assumed based on circumstantial evidence. However, the requirement for CD8+ T-cell-mediated IFN-γ production in protective immunity to this pathogen has not been directly tested. In this report, we use an adoptive transfer strategy with circumsporozoite (CS) protein-specific transgenic T cells to examine the role of CD8+ T-cell-derived IFN-γ production in Plasmodium yoelii-infected mice. We show that despite a marginal reduction in the expansion of naive IFN-γ-deficient CS-specific transgenic T cells, their antiparasite activity remains intact. Further, adoptively transferred IFN-γ-deficient CD8+ T cells were as efficient as their wild-type counterparts in limiting parasite growth in naive mice. Taken together, these studies demonstrate that IFN-γ secretion by CS-specific CD8+ T cells is not essential to protect mice against live sporozoite challenge.

scholarly journals T-bet fate mapping identifies a novel ILC1-ILC2 subset in vivo

2020 ◽  
Author(s):  
J-H Schroeder ◽  
N Garrido-Mesa ◽  
T Zabinski ◽  
AL Gallagher ◽  
L Campbell ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Immune Responses ◽  
Critical Role ◽  
Innate Lymphoid Cells ◽  
Lymphoid Cells ◽  
Fate Mapping ◽  
Functional Roles ◽  
Mucosal Surfaces ◽  
Group 2

ABSTRACTInnate lymphoid cells (ILC) play a critical role in regulating immune responses at mucosal surfaces. Various subsets exist resembling T cell lineages defined by the expression of specific transcription factors. Thus, T-bet is expressed in ILC1 and Th1 cells. In order to further understand the functional roles of T-bet in ILC, we generated a fate-mapping mouse model that permanently marks cells and their progeny that are expressing, or have ever expressed T-bet. Here we have identified and characterised a novel ILC with characteristics of ILC1 and ILC2 that are “fate-mapped” for T-bet expression and arise early in neonatal life prior to establishment of a mature microbiome. These ILC1-ILC2 cells are critically dependent on T-bet and are able to express type 1 and type 2 cytokines at steady state, but not in the context of inflammation. These findings refine our understanding of ILC lineage regulation and stability and have important implications for the understanding of ILC biology at mucosal surfaces.SUMMARYInnate lymphoid cells (ILC) play a critical role in regulating immune responses at mucosal surfaces. Three distinct ILC groups have been described according to expression of subset defining transcription factors and other markers. In this study we characterize a novel ILC subset with characteristics of group 1 and group 2 ILC in vivo.

scholarly journals IL-4 receptor expression on CD8+ T cells is required for the development of protective memory responses against liver stages of malaria parasites

2005 ◽  
Vol 202 (4) ◽  
pp. 551-560 ◽  
Author(s):  
Alexandre Morrot ◽  
Julius C.R. Hafalla ◽  
Ian A. Cockburn ◽  
Luzia H. Carvalho ◽  
Fidel Zavala
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Critical Role ◽  
Plasmodium Yoelii ◽  
T Cell Response ◽  
Receptor Expression ◽  
Memory Cells ◽  
Malaria Parasites ◽  
Antiparasitic Activity ◽  
Memory Cd8 T Cells

IL-4 receptor (IL-4R)-deficient CD8+ T cells specific for the circumsporozoite protein of Plasmodium yoelii develop a severely impaired memory response after priming with parasites. Memory CD8+ T cells lacking the IL-4R are unable to establish a stable population residing in nonlymphoid organs, although they develop normally in lymphoid organs. Because memory cells from nonlymphoid organs disappear shortly after immunization, the protective antiparasitic activity of this T cell response also is lost. These results demonstrate that IL-4/IL-4R interactions on CD8+ T cells play a critical role in modulating the development and tissue distribution of memory cells induced by parasite immunization. They also indicate that memory cells residing in nonlymphoid tissues are critical for protective immunity against malaria parasites.

scholarly journals Uninfected Mosquito Bites Confer Protection against Infection with Malaria Parasites

2007 ◽  
Vol 75 (5) ◽  
pp. 2523-2530 ◽  
Author(s):  
Michael J. Donovan ◽  
Andrew S. Messmore ◽  
Deborah A. Scrafford ◽  
David L. Sacks ◽  
Shaden Kamhawi ◽  
...  
Keyword(s):  
Malaria Infection ◽  
Vaccine Development ◽  
Plasmodium Yoelii ◽  
Parasite Development ◽  
Interleukin 12 ◽  
T Helper 1 ◽  
Malaria Parasites ◽  
Successful Vaccine ◽  
Protection Against Infection ◽  
Oxide Synthase

ABSTRACT Despite decades of research and multiple initiatives, malaria continues to be one of the world's most debilitating infectious diseases. New insights for malaria control and vaccine development will be essential to thwart the staggering worldwide impact of this disease (A. Bjorkman and A. Bhattarai, Acta Trop. 94:163-169, 2005); ultimately successful vaccine strategies will undoubtedly be multifactorial, incorporating multiple antigens and targeting diverse aspects of the malaria parasites’ biology (M. F. Good et al., Immunol. Rev. 201:254-267, 2004). Using a murine model of malaria infection, we show here that exposure to bites from uninfected mosquitoes prior to Plasmodium yoelii infection influences the local and systemic immune responses and limits parasite development within the host. In hosts preexposed to bites from uninfected mosquitoes, reduced parasite burdens in the livers were detected early, and during the blood-stage of the life cycle, these burdens remained lower than those in hosts that received mosquito bites only at the time of infection. Repeated exposure to bites from uninfected mosquitoes skewed the immune response towards a T-helper 1 (Th1) phenotype as indicated by increased levels of interleukin-12, gamma interferon, and inducible nitric oxide synthase. These data suggest that the addition of mosquito salivary components to antimalaria vaccines may be a viable strategy for creating a Th1-biased environment known to be effective against malaria infection. Furthermore, this strategy may be important for the development of vaccines to combat other mosquito-transmitted pathogens.

scholarly journals Type I Interferons and Malaria: A Double-Edge Sword Against a Complex Parasitic Disease

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao He ◽  
Lu Xia ◽  
Keyla C. Tumas ◽  
Jian Wu ◽  
Xin-Zhuan Su
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Adaptive Immune Response ◽  
Plasmodium Yoelii ◽  
Type I Interferons ◽  
Complex Life Cycle ◽  
Type I ◽  
Malaria Parasites ◽  
Cytokines And Chemokines

Type I interferons (IFN-Is) are important cytokines playing critical roles in various infections, autoimmune diseases, and cancer. Studies have also shown that IFN-Is exhibit ‘conflicting’ roles in malaria parasite infections. Malaria parasites have a complex life cycle with multiple developing stages in two hosts. Both the liver and blood stages of malaria parasites in a vertebrate host stimulate IFN-I responses. IFN-Is have been shown to inhibit liver and blood stage development, to suppress T cell activation and adaptive immune response, and to promote production of proinflammatory cytokines and chemokines in animal models. Different parasite species or strains trigger distinct IFN-I responses. For example, a Plasmodium yoelii strain can stimulate a strong IFN-I response during early infection, whereas its isogenetic strain does not. Host genetic background also greatly influences IFN-I production during malaria infections. Consequently, the effects of IFN-Is on parasitemia and disease symptoms are highly variable depending on the combination of parasite and host species or strains. Toll-like receptor (TLR) 7, TLR9, melanoma differentiation-associated protein 5 (MDA5), and cyclic GMP-AMP synthase (cGAS) coupled with stimulator of interferon genes (STING) are the major receptors for recognizing parasite nucleic acids (RNA/DNA) to trigger IFN-I responses. IFN-I levels in vivo are tightly regulated, and various novel molecules have been identified to regulate IFN-I responses during malaria infections. Here we review the major findings and progress in ligand recognition, signaling pathways, functions, and regulation of IFN-I responses during malaria infections.

scholarly journals The ApiAP2 factor PfAP2-HC is an integral component of heterochromatin in the malaria parasite Plasmodium falciparum

2020 ◽  
Author(s):  
Eilidh Carrington ◽  
Roel H. M. Cooijmans ◽  
Dominique Keller ◽  
Christa G. Toenhake ◽  
Richárd Bártfai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Dna Binding ◽  
Regulation Of Gene Expression ◽  
Complex Life Cycle ◽  
Parasite Development ◽  
Specific Gene ◽  
Mosquito Vector ◽  
Malaria Parasites

AbstractMalaria parasites undergo a highly complex life cycle in the human host and the mosquito vector. The ApiAP2 family of sequence-specific DNA-binding proteins plays a dominant role in parasite development and life cycle progression. Of the ApiAP2 factors studied to date, most act as transcription factors regulating stage-specific gene expression. Here, we characterised a new ApiAP2 factor in Plasmodium falciparum (PF3D7_1456000) that we termed PfAP2-HC. Via detailed investigation of several single or double genetically engineered parasite lines, we demonstrate that PfAP2-HC specifically binds to heterochromatin throughout the genome. Intriguingly, PfAP2-HC does not bind DNA in vivo and recruitment of PfAP2-HC to heterochromatin is independent of its DNA-binding domain but strictly dependent on heterochromatin protein 1. Furthermore, our results suggest that PfAP2-HC functions neither in the regulation of gene expression nor in heterochromatin formation or maintenance. In summary, our findings reveal that PfAP2-HC constitutes a core component of heterochromatin in malaria parasites. They furthermore identify unexpected properties of ApiAP2 factors and suggest substantial functional divergence among the members of this important family of regulatory proteins.

scholarly journals Genome-wide Identification and Functional Analysis of the H3 Gene Family in Cotton

2020 ◽  
Author(s):  
ZHANG Youping ◽  
ZHANG Jia ◽  
WANG Qiaolian ◽  
Li Simin ◽  
ZUO Dongyun ◽  
...  
Keyword(s):  
Gene Family ◽  
Developmental Stages ◽  
Leaf Growth ◽  
Critical Role ◽  
Virus Induced Gene Silencing ◽  
Rapid Phase ◽  
Conserved Sequence ◽  
Nucleosome Structure ◽  
Stomatal Guard Cells ◽  
Pistil Development

Abstract Background: Histones are major components of chromatin, which is a nucleosome structure associated with chromosome segregation, DNA packaging and transcriptional regulation. Histone H3 is encoded by many genes in most eukaryotic species, but little information is known about the Histone H3 gene family in cotton.Results: In this study, we identified and analyzed the evolution and expression of histone H3 gene family in cotton. First, 34 G. hirsutum genes were identified belonging to the H3 gene family which were divided into four subclasses: CENH3, H3.1, H3.3 and H3-like. Among these H3.1 subclass contained the highest number of genes (22 members) followed by H3.3 subclass (9 members). In addition, there were18 and 16 H3 genes identified in G. arboretum and G. raimondii, respectively. Furthermore, we conducted conserved sequence analysis of H3 proteins, and found that the four amino acids signature including A31F41S87A90 for H3.1 and T31Y41H87L90 for H3.3 could be used to discriminate H3.1 from H3.3. The expression of H3 gene family varied in different tissues and developmental stages of G. hirsutum, where H3.1 subclass genes play a critical role in pistil development. By virus-induced gene silencing of GhCENH3 (Gh_D07G1382) gene, the size of leaf got smaller with pYL156-CENH3 than that with pYL156 in TM-1. Whereas, the number of the stomata in the leaf epidermis and number of chloroplasts in the leaf stomatal guard cells by pYL156-CENH3 was more than that by pYL156 and pYL156-PDS.Conclusions: Four sub-classes (CENH3, H3.1, H3.3 and H3-like) of H3 gene family were highly conserved in cotton during the rapid phase of evolution among which CENH3 is necessary for leaf growth. These findings are useful for providing further insights into cotton biology and breeding.

scholarly journals Genome-wide identification, classification, and expression analysis of the HSF gene family in pineapple (Ananas comosus)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11329
Author(s):  
Lulu Wang ◽  
Yanhui Liu ◽  
Mengnan Chai ◽  
Huihuang Chen ◽  
Mohammad Aslam ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Gene Family ◽  
Plant Development ◽  
Developmental Stages ◽  
Stress Hormones ◽  
Functional Characterization ◽  
Ananas Comosus ◽  
Group A ◽  
Group B ◽  
Regulatory Functions

Transcription factors (TFs), such as heat shock transcription factors (HSFs), usually play critical regulatory functions in plant development, growth, and response to environmental cues. However, no HSFs have been characterized in pineapple thus far. Here, we identified 22 AcHSF genes from the pineapple genome. Gene structure, motifs, and phylogenetic analysis showed that AcHSF families were distinctly grouped into three subfamilies (12 in Group A, seven in Group B, and four in Group C). The AcHSF promoters contained various cis-elements associated with stress, hormones, and plant development processes, for instance, STRE, WRKY, and ABRE binding sites. The majority of HSFs were expressed in diverse pineapple tissues and developmental stages. The expression of AcHSF-B4b/AcHSF-B4c and AcHSF-A7b/AcHSF-A1c were enriched in the ovules and fruits, respectively. Six genes (AcHSF-A1a , AcHSF-A2, AcHSF-A9a, AcHSF-B1a, AcHSF-B2a, and AcHSF-C1a) were transcriptionally modified by cold, heat, and ABA. Our results provide an overview and lay the foundation for future functional characterization of the pineapple HSF gene family.

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