scholarly journals Uncovering the balance of forces driving microtubule aster migration in C. elegans zygotes

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
A. De Simone ◽  
A. Spahr ◽  
C. Busso ◽  
P. Gönczy
2021 ◽  
Author(s):  
Chenshu Liu ◽  
Zoe Lung ◽  
John S Wang ◽  
Fan Wu ◽  
Abby F Dernburg

Oogenesis involves meiosis and oocyte maturation. Both processes rely on mechanical forces (Lee et al., 2015; Nagamatsu et al., 2019; Rog and Dernburg, 2015; Sato et al., 2009; Tsatskis et al., 2020; Wynne et al., 2012), which can be transduced from the cytoskeleton to the nuclear envelope (NE) through linker of nucleoskeleton and cytoskeleton (LINC) complexes (Burke, 2018; Chang et al., 2015; Fan et al., 2020; Link et al., 2014). Gametes must protect their genomes from damage in this mechanically stressful environment. In C. elegans, oocyte nuclei lacking the single lamin protein LMN-1 are vulnerable to nuclear collapse. Here we deploy the auxin-inducible degradation system to investigate the balance of forces that drive this collapse and protect oocyte nuclei. We find that nuclear collapse is not a consequence of apoptosis. It is promoted by dynein and a LINC complex comprised of SUN-1 and ZYG-12, which assumes polarized distribution at the NE in response to dynein-mediated forces. We also show that the lamin meshwork works in parallel with other inner nuclear membrane (INM) proteins to counteract mechanical stress at the NE during oogenesis. We speculate that a similar network may protect oocyte integrity during the long arrest period in mammals.


2007 ◽  
Vol 179 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Miao-Chih Tsai ◽  
Julie Ahringer

Microtubules deliver positional signals and are required for establishing polarity in many different organisms and cell types. In Caenorhabditis elegans embryos, posterior polarity is induced by an unknown centrosome-dependent signal. Whether microtubules are involved in this signaling process has been the subject of controversy. Although early studies supported such an involvement (O'Connell, K.F., K.N. Maxwell, and J.G. White. 2000. Dev. Biol. 222:55–70; Wallenfang, M.R., and G. Seydoux. 2000. Nature. 408:89–92; Hamill, D.R., A.F. Severson, J.C. Carter, and B. Bowerman. 2002. Dev. Cell. 3:673–684), recent work involving RNA interference knockdown of tubulin led to the conclusion that centrosomes induce polarity independently of microtubules (Cowan, C.R., and A.A. Hyman. 2004. Nature. 431:92–96; Sonneville, R., and P. Gonczy. 2004. Development. 131: 3527–3543). In this study, we investigate the consequences of tubulin knockdown on polarity signaling. We find that tubulin depletion delays polarity induction relative to wild type and that polarity only occurs when a small, late-growing microtubule aster is visible at the centrosome. We also show that the process of a normal meiosis produces a microtubule-dependent polarity signal and that the relative levels of anterior and posterior PAR (partitioning defective) polarity proteins influence the response to polarity signaling. Our results support a role for microtubules in the induction of embryonic polarity in C. elegans.


2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.


2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.


2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.


Author(s):  
Takaaki Hirotsu ◽  
Yu Hayashi ◽  
Ryo Iwata ◽  
Hirofumi Kunitomo ◽  
Eriko Kage-Nakadai ◽  
...  

2010 ◽  
Vol 5 (03) ◽  
Author(s):  
M Pfeiffer ◽  
A Schlotterer ◽  
G Kukudov ◽  
T Fleming ◽  
A Bierhaus ◽  
...  
Keyword(s):  

Author(s):  
Aleksey E. Shishkin

Relevance. The market-imposed system of consumerism overstepped the boundaries of bifurcation and entered into “legitimate rights” to abolish the living traditional world, thereby disturbing the balance in society and thereby signed the death sentence to itself. The problem of research. Exploring the possibilities of social reloading from consumerism to communitarianism to restore the balance of power in society. Scientific novelty and research results. Our novelty of research lies in the application of scientific tools to analyze a possible reload. We used the complementarity principle of N. Bohr, the principle of spontaneous emergence of I. Prigogine, the principle of incompatibility L. Zade, the principle of managing uncertainties, the principle of ignorance of individual opinions and collective ideas, the principle of conformity, the principle of diversity of development of a complex system, the principle of unity and mutual transitions, the principle oscillatory (pulsating) evolution – showed instability in the management of society by mondialist-compradors and a possible countdown of the transition from the sensual age to the ideation nnuyu, and in our case – from consumerism to communitarianism. The main purpose of the work. From the apparent modern triumph of consumerism over communitarianism, we are not interested in a fact-problem, but in the idea of transforming reality that can stop the process of obscuration. Discussion and Conclusion. In the Middle Ages, during the construction of the project “Holy Russia”, communities were created according to the principle of “big”. Around the devotee of piety, voluntary monastic settlements were created, which grew into suburbs. Of these, the ascetic-hesychast stood out, who went into the forest and chopped down a new temple. To the righteous people flocked, yearning for a just life. This is how a new community was created. There was a new prayer book and then the big man blessed him to organize other settlements. The state should be interested in finding new forms of solutions for educational, economic, technical, cultural and food programs, therefore the initiative of communitarianists should not be punished, but supported. Today, foreign investors are becoming owners of not only factories, but even entire branches of domestic industry and are able to significantly influence domestic politics in our country. The growing number of immigrants as a destabilizing factor is becoming increasingly important. In such a situation, the fate of the country depends on the ability of the people to a new unification. It is necessary to unite on the basis of religious and cultural traditions on the principle of professional fraternities; if only there would be more centers of spiritual culture, but not by the principle of quantity, as is always the case with officials, but by the qualitative qualification of the “big man” as a center of creative and integrative power. From the foregoing, the idea of building ideational (communitarian) cohorts is born, which, through their ascetic life and creative work, should set a new vector for historical development (“salt”) consumer society.


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