5'-3' Interactions in regulation of translation in Xenopus early embryos

1997 ◽  
Vol 75 (6) ◽  
pp. 739-748
Author(s):  
Leon W Browder ◽  
Jillian Wilkes-Johnston ◽  
Sherri D Fraser
Keyword(s):  
Xenopus Laevis ◽  
Key Words ◽  
Long Range ◽  
Translational Regulation ◽  
Chloramphenicol Acetyltransferase ◽  
Hairpin Structure ◽  
Untranslated Regions ◽  
Xenopus Embryos ◽  
Early Embryos ◽  
Long Range Interactions

We have investigated the effects of 3' noncoding elements in enhancing translation of messengers having translation-inhibiting 5' untranslated regions (UTRs). The translation of transcripts bearing the 5' UTRs of either human c-myc or a synthetic hairpin structure upstream of a chloramphenicol acetyltransferase (CAT) reporter sequence is greatly attenuated in early embryos of Xenopus laevis. Translation of transcripts bearing the human c-myc-5' UTR was markedly stimulated by the presence of 3' poly(A). Transcripts bearing the 5' hairpin element were insensitive to the presence of poly(A), but they were extremely sensitive to the composition of the 3' UTR. A GC-rich distal sequence repressed translation, whereas a proximal GGAAU sequence promoted translation of these transcripts. Our results support the concept that long-range interactions between the 5' and 3' ends of transcripts are important in regulating translation in Xenopus embryos. Key words: translational regulation, oncogenes, c-myc, Xenopus laevis, development, embryo.

scholarly journals Community effects in regulation of translation

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Paul M Macdonald ◽  
Matt Kanke ◽  
Andrew Kenny
Keyword(s):  
Long Range ◽  
Translational Regulation ◽  
Regulatory Elements ◽  
Community Effects ◽  
Particle Assembly ◽  
Cis Acting ◽  
Long Range Interactions ◽  
In Trans ◽  
Single Transcript ◽  
In Cis

Certain forms of translational regulation, and translation itself, rely on long-range interactions between proteins bound to the different ends of mRNAs. A widespread assumption is that such interactions occur only in cis, between the two ends of a single transcript. However, certain translational regulatory defects of the Drosophila oskar (osk) mRNA can be rescued in trans. We proposed that inter-transcript interactions, promoted by assembly of the mRNAs in particles, allow regulatory elements to act in trans. Here we confirm predictions of that model and show that disruption of PTB-dependent particle assembly inhibits rescue in trans. Communication between transcripts is not limited to different osk mRNAs, as regulation imposed by cis-acting elements embedded in the osk mRNA spreads to gurken mRNA. We conclude that community effects exist in translational regulation.

Pattern regulation in isolated halves and blastomeres of early Xenopus laevis

Development ◽  
1983 ◽  
Vol 74 (1) ◽  
pp. 221-234
Author(s):  
H. Kageura ◽  
K. Yamana
Keyword(s):  
Xenopus Laevis ◽  
Calf Serum ◽  
The Other ◽  
Foetal Calf Serum ◽  
Cell Stage ◽  
Macroscopic Appearance ◽  
Xenopus Embryos ◽  
Early Embryos ◽  
Tailbud Stage ◽  
Pattern Regulation

Xenopus embryos at the 2-cell stage were cut into right and left halves, those at the 4-cell stage into dorsal and ventral halves or individual blastomeres, and those at the 8-cell stage into lateral, animal and vegetal halves. Defect embryos, that is, 8-cell embryos from which a particular pair of blastomeres had been removed, were also prepared. These halves, blastomeres and defect embryos were cultured in 50% Leibovitz (L-15) medium supplemented with 10% foetal calf serum and then in 10% Steinberg solution. Their development was determined from their macroscopic appearance when controls reached stage 26 (early tailbud stage) or later. The only halves that could develop into normal larvae or frogs were lateral ones of 2- and 8-cell embryos. An interesting finding was that these halves of 2-cell embryos developed into only half-embryos when cultured in the above Leibovitz medium beyond the beginning of gastrulation. On the other hand, most or all the dorsal and ventral halves at the 4-cell stage and the animal and vegetal quartets at the 8-cell stage did not form normally proportioned embryos. Defect embryos lacking any two blastomeres of the animal half gave rise to nearly normal embryos, whereas those lacking two dorsal or two ventral blastomeres of the vegetal half did not. From the present results and those of studies now in progress, it is concluded that development of blastomeres and halves from these early embryos, except lateral halves from 2- and 8-cell embryos, is not regulative as expected earlier, and that a certain combination of blastomeres is essential for complete pattern regulation.

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

scholarly journals Detecting long-range interactions between migrating cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Metzner ◽  
F. Hörsch ◽  
C. Mark ◽  
T. Czerwinski ◽  
A. Winterl ◽  
...  
Keyword(s):  
Nk Cells ◽  
Tumor Cells ◽  
Long Range ◽  
Cooperative Behavior ◽  
Simulated Data ◽  
Movement Direction ◽  
Repulsive Interaction ◽  
Collagen Gels ◽  
Long Range Interactions ◽  
A Cell

AbstractChemotaxis enables cells to systematically approach distant targets that emit a diffusible guiding substance. However, the visual observation of an encounter between a cell and a target does not necessarily indicate the presence of a chemotactic approach mechanism, as even a blindly migrating cell can come across a target by chance. To distinguish between the chemotactic approach and blind migration, we present an objective method that is based on the analysis of time-lapse recorded cell migration trajectories: For each movement step of a cell relative to the position of a potential target, we compute a p value that quantifies the likelihood of the movement direction under the null-hypothesis of blind migration. The resulting distribution of p values, pooled over all recorded cell trajectories, is then compared to an ensemble of reference distributions in which the positions of targets are randomized. First, we validate our method with simulated data, demonstrating that it reliably detects the presence or absence of remote cell-cell interactions. In a second step, we apply the method to data from three-dimensional collagen gels, interspersed with highly migratory natural killer (NK) cells that were derived from two different human donors. We find for one of the donors an attractive interaction between the NK cells, pointing to a cooperative behavior of these immune cells. When adding nearly stationary K562 tumor cells to the system, we find a repulsive interaction between K562 and NK cells for one of the donors. By contrast, we find attractive interactions between NK cells and an IL-15-secreting variant of K562 tumor cells. We therefore speculate that NK cells find wild-type tumor cells only by chance, but are programmed to leave a target quickly after a close encounter. We provide a freely available Python implementation of our p value method that can serve as a general tool for detecting long-range interactions in collective systems of self-driven agents.

scholarly journals A novel class of translationally invariant spin chains with long-range interactions

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
B. Basu-Mallick ◽  
F. Finkel ◽  
A. González-López
Keyword(s):  
Long Range ◽  
Degrees Of Freedom ◽  
Spin Chains ◽  
Open Chain ◽  
New Class ◽  
Spin Interactions ◽  
Long Range Interactions ◽  
Spin Reversal ◽  
Twisted Yangian ◽  
Internal Degrees Of Freedom

Abstract We introduce a new class of open, translationally invariant spin chains with long-range interactions depending on both spin permutation and (polarized) spin reversal operators, which includes the Haldane-Shastry chain as a particular degenerate case. The new class is characterized by the fact that the Hamiltonian is invariant under “twisted” translations, combining an ordinary translation with a spin flip at one end of the chain. It includes a remarkable model with elliptic spin-spin interactions, smoothly interpolating between the XXX Heisenberg model with anti-periodic boundary conditions and a new open chain with sites uniformly spaced on a half-circle and interactions inversely proportional to the square of the distance between the spins. We are able to compute in closed form the partition function of the latter chain, thereby obtaining a complete description of its spectrum in terms of a pair of independent su(1|1) and su(m/2) motifs when the number m of internal degrees of freedom is even. This implies that the even m model is invariant under the direct sum of the Yangians Y (gl(1|1)) and Y (gl(0|m/2)). We also analyze several statistical properties of the new chain’s spectrum. In particular, we show that it is highly degenerate, which strongly suggests the existence of an underlying (twisted) Yangian symmetry also for odd m.

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