Early transcription in Caenorhabditis elegans embryos

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 443-451 ◽  
Author(s):  
L.G. Edgar ◽  
N. Wolf ◽  
W.B. Wood

We have analysed early transcription in devitellinized, cultured embryos of the nematode Caenorhabditis elegans by two methods: measurement of [32P]UTP uptake into TCA-precipitable material and autoradiographic detection of [3H]UTP labelling both in the presence and absence of alpha-amanitin. RNA synthesis was first detected at the 8- to 12-cell stage, and alpha-amanitin sensitivity also appeared at this time, during the cleavages establishing the major founder cell lineages. The requirements for maternally supplied versus embryonically produced gene products in early embryogenesis were examined in the same culture system by observing the effects of alpha-amanitin on cell division and the early stereotyped lineage patterns. In the presence of high levels of alpha-amanitin added at varying times from two cells onward, cell division continued until approximately the 100-cell stage and then stopped during a single round of cell division. The characteristic unequal early cleavages, orientation of cleavage planes and lineage-specific timing of early divisions were unaffected by alpha-amanitin in embryos up to 87 cells. These results indicate that embryonic transcription starts well before gastrulation in C. elegans embryos, but that although embryonic transcripts may have important early functions, maternal products can support at least the mechanics of the first 6 to 7 cell cycles.

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1623-1628
Author(s):  
Hediye Nese Cinar ◽  
Keri L Richards ◽  
Kavita S Oommen ◽  
Anna P Newman

Abstract We isolated egl-13 mutants in which the cells of the Caenorhabditis elegans uterus initially appeared to develop normally but then underwent an extra round of cell division. The data suggest that egl-13 is required for maintenance of the cell fate.


Genetics ◽  
1997 ◽  
Vol 145 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Lisa C Kadyk ◽  
Eric J Lambie ◽  
Judith Kimble

The germ line is the only tissue in Caenorhabditis elegans in which a stem cell population continues to divide mitotically throughout life; hence the cell cycles of the germ line and the soma are regulated differently. Here we report the genetic and phenotypic characterization of the glp-3 gene. In animals homozygous for each of five recessive loss-of-function alleles, germ cells in both hermaphrodites and males fail to progress through mitosis and meiosis, but somatic cells appear to divide normally. Germ cells in animals grown at 15° appear by DAPI staining to be uniformly arrested at the G2/M transition with <20 germ cells per gonad on average, suggesting a checkpoint-mediated arrest. In contrast, germ cells in mutant animals grown at 25° frequently proliferate slowly during adulthood, eventually forming small germ lines with several hundred germ cells. Nevertheless, cells in these small germ lines never undergo meiosis. Double mutant analysis with mutations in other genes affecting germ cell proliferation supports the idea that glp-3 may encode a gene product that is required for the mitotic and meiotic cell cycles in the C. elegans germ line.


Development ◽  
1978 ◽  
Vol 48 (1) ◽  
pp. 37-51
Author(s):  
S. J. Kelly ◽  
J. G. Mulnard ◽  
C. F. Graham

Cell division was observed in intact and dissociated mouse embryos between the 2-cell stage and the blastocyst in embryos developing in culture. Division to the 4-cell stage was usually asynchronous. The first cell to divide to the 4-cell stage produced descendants which tended to divide ahead of those cells produced by its slow partner at all subsequent stages of development up to the blastocyte stage. The descendants of the first cell to divide to the 4-cell stage did not subsequently have short cell cycles. The first cell or last cell to divide from the 4-cell stage was labelled with tritiated thymidine. The embryo was reassembled, and it was found that the first pair of cells to reach the 8-cell stage contributed disproportionately more descendants to the ICM when compared with the last cell to divide to the 8-cell stage.


Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1227-1236 ◽  
Author(s):  
B. Goldstein

Establishment of the gut founder cell (E) in C. elegans involves an interaction between the P2 and the EMS cell at the four cell stage. Here I show that the fate of only one daughter of EMS, the E cell, is affected by this induction. In the absence of the P2-EMS interaction, both E and its sister cell, MS, produce pharyngeal muscle cells and body wall muscle cells, much as MS normally does. By cell manipulations and inhibitor studies, I show first that EMS loses the competence to respond before it divides even once, but P2 presents an inducing signal for at least three cell cycles. Second, induction on one side of the EMS cell usually blocks the other side from responding to a second P2-derived signal. Third, microfilaments and microtubules may be required near the time of the interaction for subsequent gut differentiation. Lastly, cell manipulations in pie-1 mutant embryos, in which the P2 cell is transformed to an EMS-like fate and produces a gut cell lineage, revealed that gut fate is segregated to one of P2's daughters cell-autonomously. The results contrast with previous results from similar experiments on the response to other inductions, and suggest that this induction may generate cell diversity by a different mechanism.


2010 ◽  
Vol 21 (13) ◽  
pp. 2161-2171 ◽  
Author(s):  
Kin Chan ◽  
Jesse P. Goldmark ◽  
Mark B. Roth

The orderly progression through the cell division cycle is of paramount importance to all organisms, as improper progression through the cycle could result in defects with grave consequences. Previously, our lab has shown that model eukaryotes such as Saccharomyces cerevisiae, Caenorhabditis elegans, and Danio rerio all retain high viability after prolonged arrest in a state of anoxia-induced suspended animation, implying that in such a state, progression through the cell division cycle is reversibly arrested in an orderly manner. Here, we show that S. cerevisiae (both wild-type and several cold-sensitive strains) and C. elegans embryos exhibit a dramatic decrease in viability that is associated with dysregulation of the cell cycle when exposed to low temperatures. Further, we find that when the yeast or worms are first transitioned into a state of anoxia-induced suspended animation before cold exposure, the associated cold-induced viability defects are largely abrogated. We present evidence that by imposing an anoxia-induced reversible arrest of the cell cycle, the cells are prevented from engaging in aberrant cell cycle events in the cold, thus allowing the organisms to avoid the lethality that would have occurred in a cold, oxygenated environment.


2018 ◽  
Author(s):  
Yohei Kikuchi ◽  
Akatsuki Kimura

AbstractMicroinjection is a useful method in cell biology, with which exogenous substances are introduced into a cell in a location- and time-specific manner. The Caenorhabditis elegans embryo is an important model system for cell and developmental biology. Applying microinjection to the C. elegans embryo had been difficult due to the rigid eggshell surrounding the embryo. In 2013, microinjection method using a carbon-coated quartz needle for the C. elegans embryo was reported. To prepare the needle, unfortunately, special equipment is required and thus a limited number of researchers can use this method. In this study, we established a method for the microinjection of drugs, dyes, and microbeads into the C. elegans embryo using an uncoated glass needle that can be produced in a general laboratory. This method enabled us to easily detect cell lineage up to adult stages by injecting a fluorescent dye into a blastomere. We also found a cell-non-autonomous control mechanism of cell adhesion; specifically, the injection of an actin inhibitor into one cell at the 2-cell stage enhanced adhesion between daughter cells of the other cell. Our microinjection method is expected to be used for broad studies and could facilitate various discoveries using C. elegans.


Development ◽  
2000 ◽  
Vol 127 (10) ◽  
pp. 2063-2073 ◽  
Author(s):  
S. Pichler ◽  
P. Gonczy ◽  
H. Schnabel ◽  
A. Pozniakowski ◽  
A. Ashford ◽  
...  

Asymmetric cell divisions require the establishment of an axis of polarity, which is subsequently communicated to downstream events. During the asymmetric cell division of the P(1) blastomere in C. elegans, establishment of polarity depends on the establishment of anterior and posterior cortical domains, defined by the localization of the PAR proteins, followed by the orientation of the mitotic spindle along the previously established axis of polarity. To identify genes required for these events, we have screened a collection of maternal-effect lethal mutations on chromosome II of C. elegans. We have identified a mutation in one gene, ooc-3, with mis-oriented division axes at the two-cell stage. Here we describe the phenotypic and molecular characterization of ooc-3. ooc-3 is required for the correct localization of PAR-2 and PAR-3 cortical domains after the first cell division. OOC-3 is a novel putative transmembrane protein, which localizes to a reticular membrane compartment, probably the endoplasmic reticulum, that spans the whole cytoplasm and is enriched on the nuclear envelope and cell-cell boundaries. Our results show that ooc-3 is required to form the cortical domains essential for polarity after cell division.


2020 ◽  
Vol 117 (26) ◽  
pp. 14636-14641 ◽  
Author(s):  
Joonhee Choi ◽  
Hengyun Zhou ◽  
Renate Landig ◽  
Hai-Yin Wu ◽  
Xiaofei Yu ◽  
...  

Understanding the coordination of cell-division timing is one of the outstanding questions in the field of developmental biology. One active control parameter of the cell-cycle duration is temperature, as it can accelerate or decelerate the rate of biochemical reactions. However, controlled experiments at the cellular scale are challenging, due to the limited availability of biocompatible temperature sensors, as well as the lack of practical methods to systematically control local temperatures and cellular dynamics. Here, we demonstrate a method to probe and control the cell-division timing inCaenorhabditis elegansembryos using a combination of local laser heating and nanoscale thermometry. Local infrared laser illumination produces a temperature gradient across the embryo, which is precisely measured by in vivo nanoscale thermometry using quantum defects in nanodiamonds. These techniques enable selective, controlled acceleration of the cell divisions, even enabling an inversion of division order at the two-cell stage. Our data suggest that the cell-cycle timing asynchrony of the early embryonic development inC. elegansis determined independently by individual cells rather than via cell-to-cell communication. Our method can be used to control the development of multicellular organisms and to provide insights into the regulation of cell-division timings as a consequence of local perturbations.


2020 ◽  
Vol 21 (10) ◽  
pp. 3652
Author(s):  
Dureen Samandar Eweis ◽  
Julie Plastino

The cell shape changes that ensure asymmetric cell divisions are crucial for correct development, as asymmetric divisions allow for the formation of different cell types and therefore different tissues. The first division of the Caenorhabditis elegans embryo has emerged as a powerful model for understanding asymmetric cell division. The dynamics of microtubules, polarity proteins, and the actin cytoskeleton are all key for this process. In this review, we highlight studies from the last five years revealing new insights about the role of actin dynamics in the first asymmetric cell division of the early C. elegans embryo. Recent results concerning the roles of actin and actin binding proteins in symmetry breaking, cortical flows, cortical integrity, and cleavage furrow formation are described.


Genetics ◽  
2009 ◽  
Vol 183 (3) ◽  
pp. 965-977 ◽  
Author(s):  
Annina C. Spilker ◽  
Alexia Rabilotta ◽  
Caroline Zbinden ◽  
Jean-Claude Labbé ◽  
Monica Gotta

PAR proteins (partitioning defective) are major regulators of cell polarity and asymmetric cell division. One of the par genes, par-1, encodes a Ser/Thr kinase that is conserved from yeast to mammals. In Caenorhabditis elegans, par-1 governs asymmetric cell division by ensuring the polar distribution of cell fate determinants. However the precise mechanisms by which PAR-1 regulates asymmetric cell division in C. elegans remain to be elucidated. We performed a genomewide RNAi screen and identified six genes that specifically suppress the embryonic lethal phenotype associated with mutations in par-1. One of these suppressors is mpk-1, the C. elegans homolog of the conserved mitogen activated protein (MAP) kinase ERK. Loss of function of mpk-1 restored embryonic viability, asynchronous cell divisions, the asymmetric distribution of cell fate specification markers, and the distribution of PAR-1 protein in par-1 mutant embryos, indicating that this genetic interaction is functionally relevant for embryonic development. Furthermore, disrupting the function of other components of the MAPK signaling pathway resulted in suppression of par-1 embryonic lethality. Our data therefore indicates that MAP kinase signaling antagonizes PAR-1 signaling during early C. elegans embryonic polarization.


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