scholarly journals A molecular network of conserved factors keeps ribosomes dormant in the egg

2021 ◽  
Author(s):  
Katrin Friederike Leesch ◽  
Laura Lorenzo-Orts ◽  
Carina Pribitzer ◽  
Irina Grishkovskaya ◽  
Manuel Matzinger ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Early Embryo ◽  
Active State ◽  
Molecular Network ◽  
Translational Repression ◽  
Molecular Evidence ◽  
Exit Tunnel ◽  
Translational Inhibitor

Ribosomes are produced in large quantities during oogenesis and stored in the egg. However, the egg and early embryo are translationally repressed. Using mass-spectrometry and cryo-EM analyses of ribosomes isolated from zebrafish and Xenopus eggs and embryos, we provide molecular evidence that ribosomes transition from a dormant to an active state during the first hours of embryogenesis. Dormant ribosomes are associated with four conserved factors that form two modules and occupy functionally important sites of the ribosome: a Habp4-eEF2 module that stabilizes ribosome levels and a Dap1b/Dapl1-eIF5a module that represses translation. Dap1b/Dapl1 is a newly discovered translational inhibitor that stably inserts into the polypeptide exit tunnel. Thus, a developmentally programmed, conserved ribosome state plays a key role in ribosome storage and translational repression in the egg.

A genetic pathway for regulation of tra-2 translation

Development ◽  
1997 ◽  
Vol 124 (3) ◽  
pp. 749-758 ◽  
Author(s):  
E.B. Goodwin ◽  
K. Hofstra ◽  
C.A. Hurney ◽  
S. Mango ◽  
J. Kimble
Keyword(s):  
Translational Control ◽  
Direct Repeat ◽  
Postembryonic Development ◽  
Early Embryo ◽  
Translational Repression ◽  
Female Development ◽  
Normal Pattern ◽  
Repeat Elements ◽  
Translation Repression ◽  
Translational Level

In Caenorhabditis elegans, the tra-2 sex-determining gene is regulated at the translational level by two 28 nt direct repeat elements (DREs) located in its 3′ untranslated region (3′UTR). DRF is a factor that binds the DREs and may be a trans-acting translational regulator of tra-2. Here we identify two genes that are required for the normal pattern of translational control. A newly identified gene, called laf-1, is required for translational repression by the tra-2 3′UTR. In addition, the sex-determining gene, tra-3, appears to promote female development by freeing tra-2 from laf-1 repression. Finally, we show that DRF activity correlates with translational repression of tra-2 during development and that tra-3 regulates DRF activity. We suggest that tra-3 may promote female development by releasing tra-2 from translation repression by laf-1 and that translational control is important for proper sex determination--both in the early embryo and during postembryonic development.

Role for mRNA localization in translational activation but not spatial restriction of nanos RNA

Development ◽  
1999 ◽  
Vol 126 (4) ◽  
pp. 659-669 ◽  
Author(s):  
S.E. Bergsten ◽  
E.R. Gavis
Keyword(s):  
Translational Control ◽  
Rna Localization ◽  
Early Embryo ◽  
Posterior Pole ◽  
Translational Repression ◽  
Control Element ◽  
Regulatory Sequences ◽  
Cis Acting ◽  
Body Patterning ◽  
Localization Signal

Patterning of the anterior-posterior body axis during Drosophila development depends on the restriction of Nanos protein to the posterior of the early embryo. Synthesis of Nanos occurs only when maternally provided nanos RNA is localized to the posterior pole by a large, cis-acting signal in the nanos 3′ untranslated region (3′UTR); translation of unlocalized nanos RNA is repressed by a 90 nucleotide Translational Control Element (TCE), also in the 3′UTR. We now show quantitatively that the majority of nanos RNA in the embryo is not localized to the posterior pole but is distributed throughout the cytoplasm, indicating that translational repression is the primary mechanism for restricting production of Nanos protein to the posterior. Through an analysis of transgenes bearing multiple copies of nanos 3′UTR regulatory sequences, we provide evidence that localization of nanos RNA by components of the posteriorly localized germ plasm activates its translation by preventing interaction of nanos RNA with translational repressors. This mutually exclusive relationship between translational repression and RNA localization is mediated by a 180 nucleotide region of the nanos localization signal, containing the TCE. These studies suggest that the ability of RNA localization to direct wild-type body patterning also requires recognition of multiple, unique elements within the nanos localization signal by novel factors. Finally, we propose that differences in the efficiencies with which different RNAs are localized result from the use of temporally distinct localization pathways during oogenesis.

scholarly journals Molecular basis for chirality-regulated Aβ self-assembly and receptor recognition revealed by ion mobility-mass spectrometry

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Gongyu Li ◽  
Kellen DeLaney ◽  
Lingjun Li
Keyword(s):  
Mass Spectrometry ◽  
Ion Mobility ◽  
Self Assembly ◽  
Molecular Basis ◽  
Drug Targets ◽  
Molecular Evidence ◽  
Ion Mobility Mass Spectrometry ◽  
Epitope Region ◽  
Receptor Recognition ◽  
Chiral Effects

Abstract Despite extensive efforts on probing the mechanism of Alzheimer’s disease (AD) and enormous investments into AD drug development, the lack of effective disease-modifying therapeutics and the complexity of the AD pathogenesis process suggest a great need for further insights into alternative AD drug targets. Herein, we focus on the chiral effects of truncated amyloid beta (Aβ) and offer further structural and molecular evidence for epitope region-specific, chirality-regulated Aβ fragment self-assembly and its potential impact on receptor-recognition. A multidimensional ion mobility-mass spectrometry (IM-MS) analytical platform and in-solution kinetics analysis reveal the comprehensive structural and molecular basis for differential Aβ fragment chiral chemistry, including the differential and cooperative roles of chiral Aβ N-terminal and C-terminal fragments in receptor recognition. Our method is applicable to many other systems and the results may shed light on the potential development of novel AD therapeutic strategies based on targeting the D-isomerized Aβ, rather than natural L-Aβ.

scholarly journals MALDI-TOF Mass Spectrometry Revealed Significant Lipid Variations in Follicular Fluid and Somatic Follicular Cells but Not in Enclosed Oocytes between the Large Dominant and Small Subordinate Follicles in Bovine Ovary

2020 ◽  
Vol 21 (18) ◽  
pp. 6661
Author(s):  
Priscila Silvana Bertevello ◽  
Ana-Paula Teixeira-Gomes ◽  
Valerie Labas ◽  
Luiz Cordeiro ◽  
Marie-Claire Blache ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Follicular Fluid ◽  
Lipid Composition ◽  
Cumulus Cells ◽  
Building Blocks ◽  
Early Embryo ◽  
Follicular Cells ◽  
Theca Cells ◽  
Maldi Tof Mass Spectrometry ◽  
Maldi Tof

Lipid metabolism in ovarian follicular cells supports the preparation of an enclosed oocyte to ovulation. We aimed to compare lipid composition of a dominant large follicle (LF) and subordinated small follicles (SFs) within the same ovaries. Mass spectrometry imaging displayed the differences in the distribution of several lipid features between the different follicles. Comparison of lipid fingerprints between LF and SF by Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight (MALDI-TOF) mass spectrometry revealed that in the oocytes, only 8 out of 468 detected lipids (1.7%) significantly changed their abundance (p < 0.05, fold change > 2). In contrast, follicular fluid (FF), granulosa, theca and cumulus cells demonstrated 55.5%, 14.9%, 5.3% and 9.8% of significantly varied features between LF and SF, respectively. In total, 25.2% of differential lipids were identified and indicated potential changes in membrane and signaling lipids. Tremendous changes in FF lipid composition were likely due to the stage specific secretions from somatic follicular cells that was in line with the differences observed from FF extracellular vesicles and gene expression of candidate genes in granulosa and theca cells between LF and SF. In addition, lipid storage in granulosa and theca cells varied in relation to follicular size and atresia. Differences in follicular cells lipid profiles between LF and SF may probably reflect follicle atresia degree and/or accumulation of appropriate lipids for post-ovulation processes as formation of corpus luteum. In contrast, the enclosed oocyte seems to be protected during final follicular growth, likely due in part to significant lipid transformations in surrounding cumulus cells. Therefore, the enclosed oocyte could likely keep lipid building blocks and energy resources to support further maturation and early embryo development.

225. Characterisation of a diverse secretome generated by the mouse preimplantation embryo

2008 ◽  
Vol 20 (9) ◽  
pp. 25
Author(s):  
C. O.'Neill ◽  
A. Beardsley
Keyword(s):  
Mass Spectrometry ◽  
Redox Regulation ◽  
Preimplantation Embryo ◽  
Early Embryo ◽  
Arginine Deiminase ◽  
Post Translational Modification ◽  
Preimplantation Embryo Development ◽  
Mouse Preimplantation Embryo ◽  
Esi Mass Spectrometry

This study investigated the suitability of surface-enhanced laser desorption and ionisation time-of-flight (SELDI-TOF) and electro-spray ionisation (ESI) mass spectrometry for the analysis of the proteins released by the mouse preimplantation embryo in vitro. SELDI-TOF analysis with CM10 or IMAC30 (but not Q10) chips detected a protein peak at m/z 8570 released by both C57BL6 and hybrid embryos. No other peaks unique to the embryo were identified with this method. ESI mass spectrometry of tryptic digests of embryo conditioned media identified a total of 20 proteins released during development from the zygote to blastocysts stage. Four proteins were expressed in at least 7 out of 8 cultures tested, one of these (lactate dehydrogenase B) was in all cultures. A further five proteins were in at least half of the cultures and 11 more putative proteins were detected in at least one culture. The pattern of protein secretion was not obviously different for C57BL6 or hyrid embryos. The expression of two of these proteins is essential for preimplantation embryo development (NLR family, pyrin domain containing 5 protein and peptidyl arginine deiminase, type VI). A further four proteins detected have roles in redox regulation of cells, and three others are capable of inducing post-translational modification of proteins. This study shows the feasibility of ESI mass spectrometry and the limitations of SELD-TOF mass spectrometry for identifying the proteins scereted by the preimplantation embryo in vitro. This analysis identifies a range of targets that now require detailed functional analysis to assess whether their release by the embryo is an important property of the early embryo, or an artefact of in vitro culture.

scholarly journals Emerging Technologies in Mass Spectrometry-Based DNA Adductomics

2019 ◽  
Vol 8 (2) ◽  
pp. 13 ◽  
Author(s):  
Jingshu Guo ◽  
Robert J. Turesky
Keyword(s):  
Mass Spectrometry ◽  
Dna Damage ◽  
Dna Adducts ◽  
Disease Risk ◽  
Scanning Speed ◽  
Molecular Evidence ◽  
Main Transition ◽  
Human Exposure Assessment ◽  
Covalent Modifications

The measurement of DNA adducts, the covalent modifications of DNA upon the exposure to the environmental and dietary genotoxicants and endogenously produced electrophiles, provides molecular evidence for DNA damage. With the recent improvements in the sensitivity and scanning speed of mass spectrometry (MS) instrumentation, particularly high-resolution MS, it is now feasible to screen for the totality of DNA damage in the human genome through DNA adductomics approaches. Several MS platforms have been used in DNA adductomic analysis, each of which has its strengths and limitations. The loss of 2′-deoxyribose from the modified nucleoside upon collision-induced dissociation is the main transition feature utilized in the screening of DNA adducts. Several advanced data-dependent and data-independent scanning techniques originated from proteomics and metabolomics have been tailored for DNA adductomics. The field of DNA adductomics is an emerging technology in human exposure assessment. As the analytical technology matures and bioinformatics tools become available for analysis of the MS data, DNA adductomics can advance our understanding about the role of chemical exposures in DNA damage and disease risk.

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