scholarly journals Glass confers rhabdomeric photoreceptor identity in Drosophila, but not across all metazoans

2018 ◽  
Author(s):  
F. Javier Bernardo-Garcia ◽  
Maryam Syed ◽  
Gáspár Jékely ◽  
Simon G. Sprecher
Keyword(s):  
Fruit Fly ◽  
Dna Binding Domain ◽  
Animal Kingdom ◽  
Visual Systems ◽  
Evolutionarily Conserved ◽  
Different Types ◽  
Platynereis Dumerilii ◽  
Rhabdomeric Photoreceptor ◽  
Photoreceptor Neurons ◽  
Phototransduction Cascade

ABSTRACTAcross metazoans, visual systems employ different types of photoreceptor neurons to detect light. These include rhabdomeric PRs, which exist in distantly related phyla and possess an evolutionarily conserved phototransduction cascade. While the development of rhabdomeric PRs has been thoroughly studied in the fruit fly Drosophila melanogaster, we still know very little about how they form in other species. To investigate this question, we tested whether the transcription factor Glass, which is crucial for instructing rhabdomeric PR formation in Drosophila, may play a similar role in other metazoans. Glass homologues exist throughout the animal kingdom, indicating that this protein evolved prior to the metazoan radiation. Interestingly, our work indicates that glass is not expressed in rhabdomeric photoreceptors in the planarian Schmidtea mediterranea nor in the annelid Platynereis dumerilii. Combined with a comparative analysis of the Glass DNA-binding domain, our data suggest that the fate of rhabdomeric PRs is controlled by Glass-dependent and Glass-independent mechanisms in different animal clades.

On the development of the two visual systems

2002 ◽  
Vol 25 (1) ◽  
pp. 120-120 ◽  
Author(s):  
John van der Kamp ◽  
Geert J. P. Savelsbergh
Keyword(s):  
Temporal Sequence ◽  
Visual Systems ◽  
Two Visual Systems ◽  
Different Types ◽  
Types Of Information

Norman's reconciliation of the two theories of perception is challenged because it directly leads to the nature-nurture dichotomy in the development of the two visual systems. In contrast, the proposition of a separate development of the two visual systems may be better understood as involving different types of information that follow a distinct temporal sequence.

Autophagy Defects in Skeletal Myopathies

2020 ◽  
Vol 15 (1) ◽  
pp. 261-285 ◽  
Author(s):  
Marta Margeta
Keyword(s):  
Clinical Presentation ◽  
Critical Role ◽  
Lysosomal Degradation ◽  
Cellular Mechanisms ◽  
Biological Stress ◽  
Evolutionarily Conserved ◽  
Different Types ◽  
Muscle Homeostasis ◽  
Catabolic Process ◽  
Cellular Organelles

Autophagy is an evolutionarily conserved catabolic process that targets different types of cytoplasmic cargo (such as bulk cytoplasm, damaged cellular organelles, and misfolded protein aggregates) for lysosomal degradation. Autophagy is activated in response to biological stress and also plays a critical role in the maintenance of normal cellular homeostasis; the latter function is particularly important for the integrity of postmitotic, metabolically active tissues, such as skeletal muscle. Through impairment of muscle homeostasis, autophagy dysfunction contributes to the pathogenesis of many different skeletal myopathies; the observed autophagy defects differ from disease to disease but have been shown to involve all steps of the autophagic cascade (from induction to lysosomal cargo degradation) and to impair both bulk and selective autophagy. To highlight the molecular and cellular mechanisms that are shared among different myopathies with deficient autophagy, these disorders are discussed based on the nature of the underlying autophagic defect rather than etiology or clinical presentation.

scholarly journals Mechanism of APC/CCDC20 activation by mitotic phosphorylation

2016 ◽  
Vol 113 (19) ◽  
pp. E2570-E2578 ◽  
Author(s):  
Renping Qiao ◽  
Florian Weissmann ◽  
Masaya Yamaguchi ◽  
Nicholas G. Brown ◽  
Ryan VanderLinden ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Checkpoint ◽  
Anaphase Promoting Complex ◽  
Loop Region ◽  
Evolutionarily Conserved ◽  
Terminal Loop ◽  
Different Types ◽  
Mitotic Phosphorylation ◽  
Mitotic Checkpoint Complex

Chromosome segregation and mitotic exit are initiated by the 1.2-MDa ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) and its coactivator CDC20 (cell division cycle 20). To avoid chromosome missegregation, APC/CCDC20 activation is tightly controlled. CDC20 only associates with APC/C in mitosis when APC/C has become phosphorylated and is further inhibited by a mitotic checkpoint complex until all chromosomes are bioriented on the spindle. APC/C contains 14 different types of subunits, most of which are phosphorylated in mitosis on multiple sites. However, it is unknown which of these phospho-sites enable APC/CCDC20 activation and by which mechanism. Here we have identified 68 evolutionarily conserved mitotic phospho-sites on human APC/C bound to CDC20 and have used the biGBac technique to generate 47 APC/C mutants in which either all 68 sites or subsets of them were replaced by nonphosphorylatable or phospho-mimicking residues. The characterization of these complexes in substrate ubiquitination and degradation assays indicates that phosphorylation of an N-terminal loop region in APC1 is sufficient for binding and activation of APC/C by CDC20. Deletion of the N-terminal APC1 loop enables APC/CCDC20 activation in the absence of mitotic phosphorylation or phospho-mimicking mutations. These results indicate that binding of CDC20 to APC/C is normally prevented by an autoinhibitory loop in APC1 and that its mitotic phosphorylation relieves this inhibition. The predicted location of the N-terminal APC1 loop implies that this loop controls interactions between the N-terminal domain of CDC20 and APC1 and APC8. These results reveal how APC/C phosphorylation enables CDC20 to bind and activate the APC/C in mitosis.

scholarly journals A Novel Mechanism for SUMO System Control: Regulated Ulp1 Nucleolar Sequestration

2010 ◽  
Vol 30 (18) ◽  
pp. 4452-4462 ◽  
Author(s):  
Yaroslav Sydorskyy ◽  
Tharan Srikumar ◽  
Stanley M. Jeram ◽  
Sarah Wheaton ◽  
Franco J. Vizeacoumar ◽  
...  
Keyword(s):  
Steady State ◽  
Nuclear Pore ◽  
System Control ◽  
Protein Targets ◽  
Sumo Protease ◽  
Sumo Conjugation ◽  
Evolutionarily Conserved ◽  
Different Types ◽  
Response To Stress ◽  
Necessary And Sufficient

ABSTRACT The small ubiquitin-related modifiers (SUMOs) are evolutionarily conserved polypeptides that are covalently conjugated to protein targets to modulate their subcellular localization, half-life, or activity. Steady-state SUMO conjugation levels increase in response to many different types of environmental stresses, but how the SUMO system is regulated in response to these insults is not well understood. Here, we characterize a novel mode of SUMO system control: in response to elevated alcohol levels, the Saccharomyces cerevisiae SUMO protease Ulp1 is disengaged from its usual location at the nuclear pore complex (NPC) and sequestered in the nucleolus. We further show that the Ulp1 region previously demonstrated to interact with the karyopherins Kap95 and Kap60 (amino acids 150 to 340) is necessary and sufficient for nucleolar targeting and that enforced sequestration of Ulp1 in the nucleolus significantly increases steady-state SUMO conjugate levels, even in the absence of alcohol. We have thus characterized a novel mechanism of SUMO system control in which the balance between SUMO-conjugating and -deconjugating activities at the NPC is altered in response to stress via relocalization of a SUMO-deconjugating enzyme.

scholarly journals PDZD-8 and TEX-2 regulate endosomal PI(4,5)P2 homeostasis via lipid transport to promote embryogenesis in C. elegans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Darshini Jeyasimman ◽  
Bilge Ercan ◽  
Dennis Dharmawan ◽  
Tomoki Naito ◽  
Jingbo Sun ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Early Embryo ◽  
Lipid Transfer ◽  
C Elegans ◽  
Cellular Events ◽  
Evolutionarily Conserved ◽  
Different Types ◽  
Endosomal Membranes ◽  
Membrane Compartments ◽  
Actomyosin Contraction

AbstractDifferent types of cellular membranes have unique lipid compositions that are important for their functional identity. PI(4,5)P2 is enriched in the plasma membrane where it contributes to local activation of key cellular events, including actomyosin contraction and cytokinesis. However, how cells prevent PI(4,5)P2 from accumulating in intracellular membrane compartments, despite constant intermixing and exchange of lipid membranes, is poorly understood. Using the C. elegans early embryo as our model system, we show that the evolutionarily conserved lipid transfer proteins, PDZD-8 and TEX-2, act together with the PI(4,5)P2 phosphatases, OCRL-1 and UNC-26/synaptojanin, to prevent the build-up of PI(4,5)P2 on endosomal membranes. In the absence of these four proteins, large amounts of PI(4,5)P2 accumulate on endosomes, leading to embryonic lethality due to ectopic recruitment of proteins involved in actomyosin contractility. PDZD-8 localizes to the endoplasmic reticulum and regulates endosomal PI(4,5)P2 levels via its lipid harboring SMP domain. Accumulation of PI(4,5)P2 on endosomes is accompanied by impairment of their degradative capacity. Thus, cells use multiple redundant systems to maintain endosomal PI(4,5)P2 homeostasis.

scholarly journals Mating-Induced Trade-Offs upon Egg Production versus Fertilization and Offspring’s Survival in a Sawfly with Facultative Parthenogenesis

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 693
Author(s):  
Hong Yu ◽  
Min-Rui Shi ◽  
Jin Xu ◽  
Peng Chen ◽  
Jian-Hong Liu
Keyword(s):  
Reproductive Strategies ◽  
Egg Production ◽  
Limited Resources ◽  
Animal Kingdom ◽  
Trade Offs ◽  
Reproductive Response ◽  
Evolutionarily Conserved ◽  
Egg Protection ◽  
Facultative Parthenogenesis ◽  
Induced Changes

Investigation of mating-induced trade-offs between reproduction and survival is conducive to provide evolutionary insights into reproductive strategies and aging. Here, we used RNAseq and bioinformatics to reveal mating-induced changes of genes and pathways related to reproduction and survival in female Cephalcia chuxiongica, a pine defoliator with facultative parthenogenesis and long larval dormancy. Results showed that mating induced substantial downregulation on genes and pathways associated to immunity, stress response, and longevity. However, mating induced divergent reproductive response, with downregulation on genes and pathways related to egg production while upregulation on genes and pathways related to egg fertilization. Considering the nature of limited resources in adults, low fecundity, and egg protection behavior in C. chuxiongica, we suggest that mating triggers trade-offs between reproduction and survival in this insect and females of this species may have evolved specific strategies to adapt to the environmental and hosts’ conditions, e.g., restrict whole fecundity to ensure higher fertilization and offspring’s survival. Moreover, mating induced significant responses on genes and pathways that play important roles in vertebrate reproduction while their function in insects are unclear, such as the progesterone-mediated oocyte maturation pathway; the significant regulation after mating suggests that their function may be evolutionarily conserved in animal kingdom.

scholarly journals A conserved morphogenetic mechanism for epidermal ensheathment of nociceptive sensory neurites

2018 ◽  
Author(s):  
Nan Jiang ◽  
Jeffrey P. Rasmussen ◽  
Joshua A. Clanton ◽  
Marci F. Rosenberg ◽  
Kory P. Luedke ◽  
...  
Keyword(s):  
Developmental Origins ◽  
Actin Network ◽  
Filamentous Actin ◽  
Functional Roles ◽  
Evolutionarily Conserved ◽  
Sensory Modalities ◽  
Different Types ◽  
Somatosensory Neurons ◽  
Sheath Formation ◽  
And Function

AbstractInteractions between epithelial cells and neurons influence a range of sensory modalities including taste, touch, and smell. Vertebrate and invertebrate keratinocytes/keratinocyte-like epidermal cells ensheath peripheral arbors of somatosensory neurons, including nociceptors, yet the developmental origins and functional roles of this ensheathment are largely unknown. Here, we describe an evolutionarily conserved morphogenetic mechanism for epidermal ensheathment of somatosensory neurites. We found that somatosensory neurons in Drosophila and zebrafish induce formation of epidermal sheaths, which wrap neurites of different types of neurons to different extents. Neurites induce formation of plasma membrane phosphatidylinositol 4,5-bisphosphate microdomains at nascent sheaths, followed by a filamentous actin network, and recruitment of junctional proteins that likely form autotypic junctions to seal sheaths. Finally, blocking epidermal sheath formation destabilized dendrite branches and reduced nociceptive sensitivity in Drosophila. Epidermal somatosensory neurite ensheathment is thus a deeply conserved cellular process that contributes to the morphogenesis and function of nociceptive sensory neurons.

scholarly journals Why did the UV-A-induced photoluminescent blue-green glow in trilobite eyes and exoskeletons not cause problems for trilobites?

2015 ◽  
Author(s):  
Brigitte Schoenemann ◽  
Euan N.K. Clarkson ◽  
Gábor Horváth
Keyword(s):  
High Refractive Index ◽  
Optical Quality ◽  
Aquatic Systems ◽  
Relevant Factor ◽  
Animal Kingdom ◽  
Receptor Cells ◽  
Visual Systems ◽  
Different Depths ◽  
The Difference

The calcitic lenses in the eyes of Palaeozoic trilobites are unique in the animal kingdom, although the use of calcite would have conveyed great advantages for vision in aquatic systems. Calcite lenses are transparent, and due to their high refractive index they would facilitate the focusing of light. In some respects, however, calcite lenses bear evident disadvantages. Birefringence would cause double images at different depths, but this is not a problem for trilobites since the difference in the paths of the ordinary and extraordinary rays is less than the diameter of the receptor cells. Another point, not discussed hitherto, is that calcite fluoresces when illuminated with UV-A. Here we show experimentally that calcite lenses fluoresce, and we discuss why fluorescence does not diminish the optical quality of these lenses and the image formed by them. In the environments in which the trilobites lived, UV-A would not have been a relevant factor, and thus fluorescence would not have disturbed or confused their visual system. We also argue that whatever the reason was that calcite was never again used successfully in the visual systems of aquatic arthropods, it was not fluorescence.

scholarly journals Conserved meiotic mechanisms in the cnidarian Clytia hemisphaerica revealed by Spo11 knockout

2022 ◽  
Author(s):  
Catriona Munro ◽  
Hugo Cadis ◽  
Evelyn Houliston ◽  
Jean-Ren&eacute Huynh
Keyword(s):  
Classical Model ◽  
Fruit Fly ◽  
Model Organisms ◽  
Oocyte Growth ◽  
Alternative Pathways ◽  
Functional Studies ◽  
Evolutionarily Conserved ◽  
Synaptonemal Complex Formation ◽  
Chromosome Movements

During meiosis, each duplicated chromosome pairs and recombines with its unique homolog to ensure the shuffling of genetic information across generations. Functional studies in classical model organisms have revealed a surprising diversity in the chronology and interdependency of the earliest meiotic steps such as chromosome movements, pairing, association via Synaptonemal Complex formation (synapsis), recombination and the formation of chiasmata. A key player is Spo11, an evolutionarily conserved topoisomerase-related transesterase that initiates meiotic recombination via the catalysis of programmed DNA double stranded breaks (DSBs). While DSBs are required for pairing and synapsis in budding yeast and mouse, alternative pathways are employed during female meiosis of the fruit fly and nematode Caenorhabditis elegans. Here, to provide a comparative perspective on meiotic regulation from a distinct animal clade, we chart gametogenesis in Clytia hemisphaerica jellyfish and examine the role of Spo11 using CRISPR-Cas9 mutants, generated clonally from F0 polyp colonies. Spo11 mutant females fail to assemble synaptonemal complexes and chiasmata, such that homologous chromosome pairs disperse during oocyte growth. Subsequent meiotic divisions are abnormal but produce viable progeny. Clytia thus shares an ancient eukaryotic dependence of synapsis and chromosome segregation on Spo11-generated DSBs. It provides a valuable additional experimental model for dissecting meiotic mechanisms during animal gametogenesis, and for building a comparative framework for distinguishing evolutionarily conserved versus flexible features of meiosis.

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