scholarly journals Plasmodium Kinesin-8X associates with mitotic spindles and is essential for oocyst development during parasite proliferation and transmission

2019 ◽  
Author(s):  
Mohammad Zeeshan ◽  
Fiona Shilliday ◽  
Tianyang Liu ◽  
Steven Abel ◽  
Tobias Mourier ◽  
...  
Keyword(s):  
Life Cycle ◽  
Cell Division ◽  
Gene Targeting ◽  
Intracellular Transport ◽  
Regulation Of Gene Expression ◽  
Microtubule Depolymerization ◽  
Expression Of Genes ◽  
Genome Wide ◽  
Spindle Dynamics ◽  
Chromosome Alignment

AbstractKinesin-8 proteins are microtubule motors that are often involved in regulation of mitotic spindle length and chromosome alignment. They move towards the ends of spindle microtubules and regulate the dynamics of these ends due, at least in some species, to their microtubule depolymerization activity. Plasmodium spp. exhibit an atypical endomitotic cell division in which chromosome condensation and spindle dynamics are not well understood in the different proliferative stages. Genome-wide homology analysis of Plasmodium spp. revealed the presence of two Kinesin-8 motor proteins (Kinesin-8X and Kinesin-8B). Here we have studied the biochemical properties of Kinesin-8X and its role in parasite proliferation. In vitro, Kinesin-8X showed motile and depolymerization activities like other Kinesin-8 motors. To understand its role in cell division, we have used protein tagging and live cell imaging to define the location of Plasmodium Kinesin-8X during all proliferative stages of the P berghei life cycle. Furthermore, we have used gene targeting to analyse the function of Kinesin-8X. The results reveal a spatio-temporal involvement of Kinesin-8X in spindle dynamics and its association with both mitotic and meiotic spindles and the putative microtubule organising centre (MTOC). Deletion of the Kinesin-8X gene showed that this protein is required for endomitotic division during oocyst development and is therefore necessary for parasite replication within the mosquito gut, and for transmission to the vertebrate host. Consistently, transcriptome analysis of Δkinesin-8X parasites reveals modulated expression of genes involved mainly in microtubule-based processes, chromosome organisation and the regulation of gene expression supporting a role in cell division.Author SummaryKinesins are microtubule-based motors that play key roles in intracellular transport, cell division and motility. Members of the Kinesin-8 family contribute to chromosome alignment during cell division in many eukaryotes. However, the roles of kinesins in the atypical cell division in Plasmodium, the causative agent of malaria, is not known. In contrast to many other eukaryotes, Plasmodium proliferates by endomitosis, in which genome replication and division occur within a nucleus bounded by a persistent nuclear envelope. We show that the Plasmodium genome encodes only nine kinesins and we further investigate the role of Kinesin-8X throughout the Plasmodium life cycle using biochemical and gene targeting approaches. We show that Plasmodium Kinesin-8X has microtubule-based motility and depolymerization activity. We also show that Kinesin-8X is probably localized on putative MTOCs and spindles during cell division in most of the stages of P. berghei life cycle. By gene deletion we demonstrate that Kinesin-8X is essential for normal oocyst development and sporozoite formation. Genome-wide RNA analysis of Δkinesin-8X parasites reveals modulated expression of genes involved in microtubule-based processes. Overall, the data suggest that Kinesin-8X is a molecular motor that plays essential roles during endomitosis in oocyst development in the mosquito, contributing to parasite transmission.

scholarly journals Location and function of all Plasmodium kinesins: key roles in parasite proliferation, polarity, and transmission

2021 ◽  
Author(s):  
Mohammad Zeeshan ◽  
Ravish Rashpa ◽  
David J.P. Ferguson ◽  
Steven Abel ◽  
Zeinab Chahine ◽  
...  
Keyword(s):  
Cell Division ◽  
Intracellular Transport ◽  
Spindle Assembly ◽  
Mammalian Host ◽  
Mosquito Vector ◽  
Parasite Transmission ◽  
Genome Wide ◽  
A Genome ◽  
And Function ◽  
Comprehensive Study

Kinesins are microtubule-based motors important in cell division, motility, polarity, and intracellular transport in many eukaryotes, but poorly studied in eukaryotic pathogens. Plasmodium, the causative agent of malaria, is a divergent eukaryote with atypical aspects of cell division and plasticity of morphology throughout its lifecycle in both mammalian and mosquito hosts. Here we describe a genome-wide screen of all nine Plasmodium kinesins, revealing diverse subcellular locations and functions in spindle assembly, axoneme formation, and cell morphology. Surprisingly, only kinesin-13 has an essential role for growth in the mammalian host while the other eight kinesins are required during the proliferative and invasive stages of parasite transmission through the mosquito vector. In-depth analyses of kinesin-13 and kinesin-20 revealed functions in microtubule (MT) dynamics during apical polarity formation, spindle assembly, and axoneme biogenesis. This comprehensive study will inform the targeting of MT motors for therapeutic intervention in malaria.

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

scholarly journals Dynamic histone acetylation in floral volatile synthesis and emission in petunia flowers

2021 ◽  
Author(s):  
Ryan M Patrick ◽  
Xing-Qi Huang ◽  
Natalia Dudareva ◽  
Ying Li
Keyword(s):  
Transcriptional Activation ◽  
Metabolic Pathways ◽  
Transcriptional Repression ◽  
Metabolic Networks ◽  
Underlying Mechanism ◽  
Expression Of Genes ◽  
Genome Wide ◽  
Chemical Inhibitors ◽  
Volatile Organic ◽  
Floral Volatile

Abstract Biosynthesis of secondary metabolites relies on primary metabolic pathways to provide precursors, energy, and cofactors, thus requiring coordinated regulation of primary and secondary metabolic networks. However, to date, it remains largely unknown how this coordination is achieved. Using Petunia hybrida flowers, which emit high levels of phenylpropanoid/benzenoid volatile organic compounds (VOCs), we uncovered genome-wide dynamic deposition of histone H3 lysine 9 acetylation (H3K9ac) during anthesis as an underlying mechanism to coordinate primary and secondary metabolic networks. The observed epigenome reprogramming is accompanied by transcriptional activation at gene loci involved in primary metabolic pathways that provide precursor phenylalanine, as well as secondary metabolic pathways to produce volatile compounds. We also observed transcriptional repression among genes involved in alternative phenylpropanoid branches that compete for metabolic precursors. We show that GNAT family histone acetyltransferase(s) (HATs) are required for the expression of genes involved in VOC biosynthesis and emission, by using chemical inhibitors of HATs, and by knocking down a specific HAT gene, ELP3, through transient RNAi. Together, our study supports that regulatory mechanisms at chromatin level may play an essential role in activating primary and secondary metabolic pathways to regulate VOC synthesis in petunia flowers.

scholarly journals Cysteine-Rich Hydrophobin Gene Family: Genome Wide Analysis, Phylogeny and Transcript Profiling in Cordyceps militaris

2021 ◽  
Vol 22 (2) ◽  
pp. 643
Author(s):  
Xiao Li ◽  
Fen Wang ◽  
Yanyan Xu ◽  
Guijun Liu ◽  
Caihong Dong
Keyword(s):  
Life Cycle ◽  
Pathogenic Fungi ◽  
Class Ii ◽  
Cordyceps Militaris ◽  
Transcript Profiling ◽  
Saprotrophic Fungi ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Encoding Genes

Hydrophobins are a family of small secreted proteins found exclusively in fungi, and they play various roles in the life cycle. In the present study, genome wide analysis and transcript profiling of the hydrophobin family in Cordyceps militaris, a well-known edible and medicinal mushroom, were studied. The distribution of hydrophobins in ascomycetes with different lifestyles showed that pathogenic fungi had significantly more hydrophobins than saprotrophic fungi, and class II members accounted for the majority. Phylogenetic analysis of hydrophobin proteins from the species of Cordyceps s.l. indicated that there was more variability among the class II members than class I. Only a few hydrophobin-encoding genes evolved by duplication in Cordyceps s.l., which was inconsistent with the important role of gene duplication in basidiomycetes. Different transcript patterns of four hydrophobin-encoding genes during the life cycle indicated the possible different functions for each. The transcripts of Cmhyd2, 3 and 4 can respond to light and were related with the photoreceptors. CmQHYD, with four hydrophobin II domains, was first found in C. militaris, and multi-domain hydrophobins were only distributed in the species of Cordycipitaceae and Clavicipitaceae. These results could be helpful for further function research of hydrophobins and could provide valuable information for the evolution of hydrophobins.

scholarly journals Genome-Wide Expression Patterns of Rhoptry Kinases during the Eimeria tenella Life-Cycle

2021 ◽  
Vol 9 (8) ◽  
pp. 1621
Author(s):  
Adeline Ribeiro E Silva ◽  
Alix Sausset ◽  
Françoise I. Bussière ◽  
Fabrice Laurent ◽  
Sonia Lacroix-Lamandé ◽  
...  
Keyword(s):  
Life Cycle ◽  
Expression Patterns ◽  
Housekeeping Genes ◽  
Catalytic Triad ◽  
Eimeria Tenella ◽  
Apicomplexan Parasites ◽  
Genome Wide ◽  
Infected Cells ◽  
First And Second Generation

Kinome from apicomplexan parasites is composed of eukaryotic protein kinases and Apicomplexa specific kinases, such as rhoptry kinases (ROPK). Ropk is a gene family that is known to play important roles in host–pathogen interaction in Toxoplasma gondii but is still poorly described in Eimeria tenella, the parasite responsible for avian coccidiosis worldwide. In the E. tenella genome, 28 ropk genes are predicted and could be classified as active (n = 7), inactive (incomplete catalytic triad, n = 12), and non-canonical kinases (active kinase with a modified catalytic triad, n = 9). We characterized the ropk gene expression patterns by real-time quantitative RT-PCR, normalized by parasite housekeeping genes, during the E. tenella life-cycle. Analyzed stages were: non-sporulated oocysts, sporulated oocysts, extracellular and intracellular sporozoites, immature and mature schizonts I, first- and second-generation merozoites, and gametes. Transcription of all those predicted ropk was confirmed. The mean intensity of transcription was higher in extracellular stages and 7–9 ropk were specifically transcribed in merozoites in comparison with sporozoites. Transcriptional profiles of intracellular stages were closely related to each other, suggesting a probable common role of ROPKs in hijacking signaling pathways and immune responses in infected cells. These results provide a solid basis for future functional analysis of ROPK from E. tenella.

The logic of cell division in the life cycle of yeast

Science ◽  
1992 ◽  
Vol 257 (5070) ◽  
pp. 626-626 ◽  
Author(s):  
C. Gimeno ◽  
G. Fink
Keyword(s):  
Life Cycle ◽  
Cell Division

scholarly journals Transcriptomic analysis reveals metabolic switches and surface remodeling as key processes for stage transition inTrypanosoma cruzi

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3017 ◽  
Author(s):  
Luisa Berná ◽  
Maria Laura Chiribao ◽  
Gonzalo Greif ◽  
Matias Rodriguez ◽  
Fernando Alvarez-Valin ◽  
...  
Keyword(s):  
Life Cycle ◽  
Regulation Of Gene Expression ◽  
Krebs Cycle ◽  
Surface Proteins ◽  
Insect Vector ◽  
Specific Expression ◽  
Major Life ◽  
Specific Subset ◽  
Regulation Of Cell Cycle ◽  
Surface Glycoproteins

American trypanosomiasis is a chronic and endemic disease which affects millions of people.Trypanosoma cruzi, its causative agent, has a life cycle that involves complex morphological and functional transitions, as well as a variety of environmental conditions. This requires a tight regulation of gene expression, which is achieved mainly by post-transcriptional regulation. In this work we conducted an RNAseq analysis of the three major life cycle stages ofT. cruzi, amastigotes, epimastigotes and trypomastigotes. This analysis allowed us to delineate specific transcriptomic profiling for each stage, and also to identify those biological processes of major relevance in each state. Stage specific expression profiling evidenced the plasticity ofT. cruzito adapt quickly to different conditions, with particular focus on membrane remodeling and metabolic shifts along the life cycle. Epimastigotes, which replicate in the gut of insect vector, showed higher expression of genes related to energy metabolism, mainly Krebs cycle, respiratory chain and oxidative phosphorylation related genes, and anabolism related genes associated to nucleotide and steroid biosynthesis; also a general down-regulation of surface glycoproteins was seen at this stage. Trypomastigotes, living extracellularly in the bloodstream of mammals, express a plethora of surface proteins and signaling genes involved in invasion and evasion of immune response. Amastigotes mostly express membrane transporters and genes involved in regulation of cell cycle, an also express a specific subset of surface glycoproteins coding genes. In addition, these results allowed us to improve the annotation of Dm28c genome, identifying new ORFs and set the stage for construction of networks of co-expression, which can give clues about coded proteins of unknown functions.

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