scholarly journals Evolutionary conservation of centriole rotational asymmetry in the human centrosome

2021 ◽  
Author(s):  
No&eacutemie GAUDIN ◽  
Paula MARTIN GIL ◽  
Meriem BOUMENDJEL ◽  
Dmitry ERSHOV ◽  
Catherine PIOCHE-DURIEU ◽  
...  
Keyword(s):  
Evolutionary Conservation ◽  
Joubert Syndrome ◽  
Distal Region ◽  
Human Cells ◽  
Cellular Organization ◽  
Animal Cells ◽  
Molecular Features ◽  
Multiciliated Cells ◽  
Induced Defects ◽  
Ciliary Signaling

Centrioles are formed by microtubule triplets in a nine-fold symmetric arrangement. In flagellated protists and in multiciliated cells, accessory structures tethered to specific triplets render the centrioles rotationally asymmetric, a property that is key to cytoskeletal and cellular organization in these contexts. In contrast, centrioles within the centrosome of animal cells display no conspicuous rotational asymmetry. Here, we uncover rotationally asymmetric molecular features in human centrioles. Using ultrastructure expansion microscopy, we show that LRRCC1, the ortholog of a protein originally characterized in flagellate green algae, associates preferentially to two consecutive triplets in the distal lumen of human centrioles. LRRCC1 partially co-localizes and affects the recruitment of another distal component, C2CD3, which also has an asymmetric localization pattern in the centriole lumen. Together, LRRCC1 and C2CD3 delineate a structure reminiscent of a filamentous density observed by electron microscopy in flagellates, termed the acorn. Functionally, the depletion of LRRCC1 in human cells induced defects in centriole structure, ciliary assembly and ciliary signaling, supporting that LRRCC1 cooperates with C2CD3 to organizing the distal region of centrioles. Since a mutation in the LRRCC1 gene has been identified in Joubert syndrome patients, this finding is relevant in the context of human ciliopathies. Taken together, our results demonstrate that rotational asymmetry is a conserved ancient property of centrioles. Our work also reveals that asymmetrically localized proteins are key for primary ciliogenesis and ciliary signaling in human cells.

scholarly journals Actin and microtubules drive differential aspects of planar cell polarity in multiciliated cells

2011 ◽  
Vol 195 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Michael E. Werner ◽  
Peter Hwang ◽  
Fawn Huisman ◽  
Peter Taborek ◽  
Clare C. Yu ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Planar Cell Polarity ◽  
Cell Polarization ◽  
Actin Dynamics ◽  
Cellular Organization ◽  
Cytoplasmic Microtubule ◽  
Local Coordination ◽  
Multiciliated Cells ◽  
Global Coordination ◽  
Microtubule Networks

Planar cell polarization represents the ability of cells to orient within the plane of a tissue orthogonal to the apical basal axis. The proper polarized function of multiciliated cells requires the coordination of cilia spacing and cilia polarity as well as the timing of cilia beating during metachronal synchrony. The planar cell polarity pathway and hydrodynamic forces have been shown to instruct cilia polarity. In this paper, we show how intracellular effectors interpret polarity to organize cellular morphology in accordance with asymmetric cellular function. We observe that both cellular actin and microtubule networks undergo drastic reorganization, providing differential roles during the polarized organization of cilia. Using computational angular correlation analysis of cilia orientation, we report a graded cellular organization downstream of cell polarity cues. Actin dynamics are required for proper cilia spacing, global coordination of cilia polarity, and coordination of metachronic cilia beating, whereas cytoplasmic microtubule dynamics are required for local coordination of polarity between neighboring cilia.

scholarly journals Transfer of Viral Communities between Human Individuals during Fecal Microbiota Transplantation

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Christel Chehoud ◽  
Anatoly Dryga ◽  
Young Hwang ◽  
Dorottya Nagy-Szakal ◽  
Emily B. Hollister ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Fecal Microbiota Transplantation ◽  
Case Series ◽  
Fecal Microbiota ◽  
Temperate Phage ◽  
Human Cells ◽  
Animal Cells ◽  
Healthy Human ◽  
Human Donor ◽  
Viral Communities

ABSTRACT Fecal microbiota transplantation (FMT) is a highly effective treatment for refractory Clostridium difficile infections. However, concerns persist about unwanted cotransfer of pathogenic microbes such as viruses. Here we studed FMT from a single healthy human donor to three pediatric ulcerative colitis patients, each of whom received a course of 22 to 30 FMT treatments. Viral particles were purified from donor and recipient stool samples and sequenced; the reads were then assembled into contigs corresponding to viral genomes or partial genomes. Transfer of selected viruses was confirmed by quantitative PCR. Viral contigs present in the donor could be readily detected in recipients, with up to 32 different donor viral contigs appearing in a recipient sample. Reassuringly, none of these were viruses are known to replicate on human cells. Instead, viral contigs either scored as bacteriophage or could not be attributed taxonomically, suggestive of unstudied phage. The two most frequently transferred gene types were associated with temperate-phage replication. In addition, members of Siphoviridae , the group of typically temperate phages that includes phage lambda, were found to be transferred with significantly greater efficiency than other groups. On the basis of these findings, we propose that the temperate-phage replication style may promote efficient phage transfer between human individuals. In summary, we documented transfer of multiple viral lineages between human individuals through FMT, but in this case series, none were from viral groups known to infect human cells. IMPORTANCE Transfer of whole communities of viruses between humans has rarely been studied but is of likely medical importance. Here we studied fecal microbiota transplantation (FMT), a highly successful treatment for relapsing Clostridium difficile infection and, potentially, other gastrointestinal (GI) diseases. We investigated the transfer of viral communities during FMT and documented transfer of multiple viral lineages between humans. None of these were viruses that replicated on animal cells or that are known to be pathogenic. We found that temperate bacteriophage, which form stable associations with their hosts, were significantly more likely to be transferred during FMT. This supports a model in which the viral temperate replication style may have evolved in part to support efficient viral transmission between environments.

scholarly journals Rad51-mediated replication fork reversal is a global response to genotoxic treatments in human cells

2015 ◽  
Vol 208 (5) ◽  
pp. 563-579 ◽  
Author(s):  
Ralph Zellweger ◽  
Damian Dalcher ◽  
Karun Mutreja ◽  
Matteo Berti ◽  
Jonas A. Schmid ◽  
...  
Keyword(s):  
Replication Fork ◽  
Genotoxic Stress ◽  
Human Cells ◽  
Chromosomal Breakage ◽  
Checkpoint Activation ◽  
Topoisomerase 1 ◽  
Molecular Features ◽  
Promising Target ◽  
Topoisomerase Poisons ◽  
Dna Synthesis Inhibitors

Replication fork reversal protects forks from breakage after poisoning of Topoisomerase 1. We here investigated fork progression and chromosomal breakage in human cells in response to a panel of sublethal genotoxic treatments, using other topoisomerase poisons, DNA synthesis inhibitors, interstrand cross-linking inducers, and base-damaging agents. We used electron microscopy to visualize fork architecture under these conditions and analyzed the association of specific molecular features with checkpoint activation. Our data identify replication fork uncoupling and reversal as global responses to genotoxic treatments. Both events are frequent even after mild treatments that do not affect fork integrity, nor activate checkpoints. Fork reversal was found to be dependent on the central homologous recombination factor RAD51, which is consistently present at replication forks independently of their breakage, and to be antagonized by poly (ADP-ribose) polymerase/RECQ1-regulated restart. Our work establishes remodeling of uncoupled forks as a pivotal RAD51-regulated response to genotoxic stress in human cells and as a promising target to potentiate cancer chemotherapy.

scholarly journals Regulatory aspects for Biologic Product licensing in Australia

2019 ◽  
Vol 7 (2) ◽  
pp. 1-6
Author(s):  
Sanjeev Kumar Maurya ◽  
Vikesh Kumar Shukla ◽  
Sunny Kumar Maurya ◽  
Prachi Kaushik
Keyword(s):  
Human Cells ◽  
Human Tissues ◽  
Animal Cells ◽  
Regulatory Requirements ◽  
Live Animal ◽  
Regulatory Aspects ◽  
Physiological Processes ◽  
Market Authorization ◽  
Regulatory Guidelines ◽  
Biologic Product

The TG Act defines biological as product made, from or containing, human cells or human tissues, lives animal organs, cells or tissues, and that is used to treat or prevent disease or injury, Diagnose a condition of a person and Alter the physiological processes of a person. The Australian Regulatory Guidelines for Biologicals (ARGB) provide the keen information for manufacturers, sponsors, professionals in healthcare and also to public about the use of human cells and tissues based therapeutic goods, live animal cells, organs and tissues (1). These all products are Biologicals. This guideline is specially written for general public. If you are a sponsor or manufacture, this will: Explains the biological regulatory framework is applies to manufacturer’s product and their exemption conditions (1). Explains the Australian regulatory requirements for supplying of Biologicals Explains what is required for the market authorization as per TGA especially for Biologicals.

scholarly journals ppGpp functions as an alarmone in metazoa

2019 ◽  
Author(s):  
Doshun Ito ◽  
Hinata Kawamura ◽  
Akira Oikawa ◽  
Yuta Ihara ◽  
Toshio Shibata ◽  
...  
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Environmental Changes ◽  
Nutrient Deficiency ◽  
Stringent Response ◽  
Human Cells ◽  
Metabolic Changes ◽  
Animal Cells ◽  
Physiological Relevance ◽  
And Function

AbstractGuanosine 3’,5’-bis(pyrophosphate) (ppGpp) functions as a second messenger in bacteria to adjust their physiology in response to environmental changes. In recent years, the ppGpp-specific hydrolase, metazoan SpoT homolog-1 (Mesh1), was shown to have important roles for growth under nutrient deficiency in Drosophila melanogaster. Curiously, however, ppGpp has never been detected in animal cells, and therefore the physiological relevance of this molecule, if any, in metazoans has not been established. Here, we report the detection of ppGpp in Drosophila and human cells and demonstrate that ppGpp accumulation induces metabolic changes, cell death, and eventually lethality in Drosophila. Our results provide the first evidence of the existence and function of the ppGpp-dependent stringent response in animals.

scholarly journals Protein turnover dynamics suggest a diffusion-to-capture mechanism for peri-basal body recruitment and retention of intraflagellar transport proteins

2021 ◽  
pp. mbc.E20-11-0717
Author(s):  
Jaime V.K. Hibbard ◽  
Neftali Vazquez ◽  
Rohit Satija ◽  
John B. Wallingford
Keyword(s):  
Protein Dynamics ◽  
Basal Body ◽  
Fluorescence Recovery After Photobleaching ◽  
Protein Complexes ◽  
Intraflagellar Transport ◽  
Basal Bodies ◽  
Multiciliated Cells ◽  
Capture Mechanism ◽  
Body Components ◽  
Ciliary Signaling

Intraflagellar transport (IFT) is essential for construction and maintenance of cilia. IFT proteins concentrate at the basal body, where they are thought to assemble into trains and bind cargoes for transport. To study the mechanisms of IFT recruitment to this peri-basal body pool, we quantified protein dynamics of eight IFT proteins, as well as five other basal body localizing proteins, using fluorescence recovery after photobleaching in vertebrate multiciliated cells. We found that members of the IFT-A and IFT-B protein complexes show distinct turnover kinetics from other basal body components. Additionally, known IFT sub-complexes displayed shared dynamics, suggesting shared basal body recruitment and/or retention mechanisms. Finally, we evaluated the mechanisms of basal body recruitment by depolymerizing cytosolic MTs, which suggested that IFT proteins are recruited to basal bodies through a diffusion-to-capture mechanism. Our survey of IFT protein dynamics provides new insights into IFT recruitment to basal bodies, a crucial step in ciliogenesis and ciliary signaling.

Surprising S1-resistant trimolecular hybrids: potential complication in interpretation of S1 mapping analyses

1985 ◽  
Vol 5 (10) ◽  
pp. 2842-2846
Author(s):  
M A Lopata ◽  
B Sollner-Webb ◽  
D W Cleveland
Keyword(s):  
Distal Region ◽  
Analytical Tool ◽  
Dna Probe ◽  
Dna Transfection ◽  
Potential Complication ◽  
Animal Cells ◽  
Rna Molecules ◽  
S1 Mapping ◽  
Powerful Analytical Tool

Although the technique of S1 mapping is a powerful analytical tool for the analysis of RNA, we now report a surprising complication involving a trimolecular hybrid between two RNA species and a single DNA probe molecule which, if unrecognized, can lead to misleading interpretations. We document that such trimolecular hybrids can be efficiently formed under some hybridization conditions and that the probe DNA sequence at the junction of the two RNA molecules can be remarkably stable to digestion with S1. Trimolecular hybrids can arise in any instance whenever a distal region of an end-labeled DNA probe is homologous to a moderately abundant RNA in the sample to be analyzed. This situation presents a serious, potential complication for a variety of S1 analyses, particularly those in which DNA transfection has been utilized to reintroduce in vitro-engineered genes into cultured animal cells.

Lectins as markers of endothelial cells: comparative study between human and animal cells

1988 ◽  
Vol 22 (2) ◽  
pp. 135-140 ◽  
Author(s):  
F. Roussel ◽  
J. Dalion
Keyword(s):  
Endothelial Cells ◽  
Monoclonal Antibodies ◽  
Comparative Study ◽  
Vascular Endothelial Cells ◽  
Human Cells ◽  
Point Of View ◽  
Laboratory Animals ◽  
Vascular Endothelial ◽  
Animal Cells ◽  
Common Laboratory

Vascular endothelial cells were labelled with 10 vegetal lectins and 3 more monoclonal antibodies antiblood group ABO substances, in major organs of 14 common laboratory animals. After fixation in PLPa and paraffin embedding, cells were examined to determine their likeness to human cells. The most interesting reactive used was EEA, whose positivity defines upper mammalians. Blood B substance positivity and CSA negativity defines primates among which man is unique and defined by UEA I positivity and variability in ABO substance. CSA positivity defines non-primate upper mammalians. Rodents and birds were negative with all reactives tested. From the histochemical point of view, the animals closest to humans are monkeys, followed by swine and oxen, then by cat and dog and lastly by sheep. Rodents appear unrelated to humans in this system.

scholarly journals miR-124 regulates Notch and NeuroD1 to mediate transition states of neuronal development

2021 ◽  
Author(s):  
Kalin Diane Konrad ◽  
Jia L. Song
Keyword(s):  
Sea Urchin ◽  
Regulatory Networks ◽  
Neuronal Development ◽  
Swimming Velocity ◽  
Animal Cells ◽  
Regulate Gene Expression ◽  
Larval Stages ◽  
Mature Neurons ◽  
Post Transcriptional Regulation ◽  
Induced Defects

MicroRNAs (miRNAs) regulate gene expression by destabilizing target mRNA and/or inhibiting translation in animal cells. The ability to mechanistically dissect the function of miR-124 during specification, differentiation, and maturation of neurons during development within a single system has not been accomplished. Using the sea urchin (Strongylocentrotus purpuratus) embryo, we take advantage of the manipulability of the embryo and its well-documented gene regulatory networks (GRNs). We incorporated NeuroD1 as part of the sea urchin neuronal GRN and determined that miR-124 inhibition resulted in decreased gut contractions, swimming velocity, and neuronal development. We further integrated post-transcriptional regulation of miR-124 into the neuronal GRN. Inhibition of miR-124 resulted in increased number of cells expressing transcription factors associated with progenitor neurons and a concurrent decrease of mature and functional neurons. Results revealed that miR-124 regulates undefined factors early in neurogenesis during neuronal specification and differentiation in the early blastula and gastrula stages. In the late gastrula and larval stages, miR-124 regulates Notch and NeuroD1. Specifically, miR-124 regulates the transition between neuronal differentiation and maturation, by directly suppressing NeuroD1. Removal of miR-124 ″s suppression of NeuroD1 results in increased mature neurons with decreased Synaptagmin B-positive mature, functional neurons. By removing both miR-124 suppression of NeuroD1 and Notch, we were able to phenocopy miR-124 inhibitor induced defects. Overall, we have improved the neuronal GRN and identified miR-124 to play a prolific role in regulating various transitions of neuronal development.

scholarly journals Mechanisms of Human Mitochondrial DNA Maintenance: The Determining Role of Primary Sequence and Length over Function

1999 ◽  
Vol 10 (10) ◽  
pp. 3345-3356 ◽  
Author(s):  
Carlos T. Moraes ◽  
Lesley Kenyon ◽  
Huiling Hao
Keyword(s):  
Mitochondrial Dna ◽  
Oxidative Phosphorylation ◽  
Copy Number ◽  
Human Cells ◽  
Mtdna Copy Number ◽  
Molecular Features ◽  
Mtdna Replication ◽  
Selection For ◽  
Dna Maintenance

Although the regulation of mitochondrial DNA (mtDNA) copy number is performed by nuclear-coded factors, very little is known about the mechanisms controlling this process. We attempted to introduce nonhuman ape mtDNA into human cells harboring either no mtDNA or mutated mtDNAs (partial deletion and tRNA gene point mutation). Unexpectedly, only cells containing no mtDNA could be repopulated with nonhuman ape mtDNA. Cells containing a defective human mtDNA did not incorporate or maintain ape mtDNA and therefore died under selection for oxidative phosphorylation function. On the other hand, foreign human mtDNA was readily incorporated and maintained in these cells. The suicidal preference for self-mtDNA showed that functional parameters associated with oxidative phosphorylation are less relevant to mtDNA maintenance and copy number control than recognition of mtDNA self-determinants. Non–self-mtDNA could not be maintained into cells with mtDNA even if no selection for oxidative phosphorylation was applied. The repopulation kinetics of several mtDNA forms after severe depletion by ethidium bromide treatment showed that replication and maintenance of mtDNA in human cells are highly dependent on molecular features, because partially deleted mtDNA molecules repopulated cells significantly faster than full-length mtDNA. Taken together, our results suggest that mtDNA copy number may be controlled by competition for limiting levels of trans-acting factors that recognize primarily mtDNA molecular features. In agreement with this hypothesis, marked variations in mtDNA levels did not affect the transcription of nuclear-coded factors involved in mtDNA replication.

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