scholarly journals A transgenic system for targeted ablation of reproductive and maternal-effect genes

Development ◽  
2021 ◽  
Vol 148 (12) ◽  
Author(s):  
Sylvain Bertho ◽  
Odelya Kaufman ◽  
KathyAnn Lee ◽  
Adrian Santos-Ledo ◽  
Daniel Dellal ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Maternal Effect ◽  
Early Embryo ◽  
Gene Products ◽  
Reverse Genetic ◽  
Genetic Screens ◽  
Maternal Effect Genes ◽  
Forward Genetic Screens ◽  
Embryonic Life ◽  
Bucky Ball

ABSTRACT Maternally provided gene products regulate the earliest events of embryonic life, including formation of the oocyte that will develop into an egg, and eventually into an embryo. Forward genetic screens have provided invaluable insights into the molecular regulation of embryonic development, including the essential contributions of some genes whose products must be provided to the transcriptionally silent early embryo for normal embryogenesis, called maternal-effect genes. However, other maternal-effect genes are not accessible due to their essential zygotic functions during embryonic development. Identifying these regulators is essential to fill the large gaps in our understanding of the mechanisms and molecular pathways contributing to fertility and to maternally regulated developmental processes. To identify these maternal factors, it is necessary to bypass the earlier requirement for these genes so that their potential later functions can be investigated. Here, we report reverse genetic systems to identify genes with essential roles in zebrafish reproductive and maternal-effect processes. As proof of principle and to assess the efficiency and robustness of mutagenesis, we used these transgenic systems to disrupt two genes with known maternal-effect functions: kif5ba and bucky ball.

scholarly journals A Transgenic System for Targeted Ablation of Reproductive and Maternal-Effect genes

2020 ◽  
Author(s):  
Sylvain Bertho ◽  
Odelya Kaufman ◽  
KathyAnn Lee ◽  
Adrian Santos-Ledo ◽  
Daniel Dellal ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Maternal Effect ◽  
Early Embryo ◽  
Reverse Genetic ◽  
Genetic Screens ◽  
Maternal Effect Genes ◽  
Genetic Systems ◽  
Forward Genetic Screens ◽  
Embryonic Life ◽  
Summary Statement

AbstractMaternally provided gene products regulate the earliest events of embryonic life, including formation of the oocyte that will develop into an egg, and eventually an embryo. Forward genetic screens have provided invaluable insights into the molecular regulation of embryonic development, including essential contributions of some genes whose products must be provided to the transcriptionally silent early embryo for normal embryogenesis, maternal-effect genes. However, other maternal-effect genes are not accessible due to their essential zygotic functions during embryonic development. Identifying these regulators is essential to fill the large gaps in our understanding of the mechanisms and molecular pathways contributing to fertility and maternally regulated developmental processes. To identify these maternal factors, it is necessary to bypass the earlier requirement for these genes so that their potential later functions can be investigated. Here we report reverse genetic systems to identify genes with essential roles in reproductive and maternal-effect processes, as proof of principal and to assess the efficiency and robustness of mutagenesis we used these transgenic systems to disrupt two genes with known maternal-effect functions, kif5Ba and bucky ball.Summary StatementWe report reverse genetic systems to identify essential regulators of reproductive and maternal-effect processes, as proof of principal we used these transgenic systems to disrupt genes with known maternal-effect functions.

scholarly journals Zebrafish embryonic development is induced by carp sperm

2016 ◽  
Vol 12 (11) ◽  
pp. 20160628 ◽  
Author(s):  
Thomas A. Delomas ◽  
Konrad Dabrowski
Keyword(s):  
Nervous System ◽  
Linkage Analysis ◽  
Embryonic Development ◽  
Common Carp ◽  
Genetic Screens ◽  
Characteristic Set ◽  
Zebrafish Development ◽  
Functional Development ◽  
Forward Genetic Screens

Haploid gynogenetic screens increase the efficiency of forward genetic screens and linkage analysis in fish. Typically, UV-irradiated zebrafish sperm is used to activate zebrafish oocytes for haploid screens. We describe the use of UV-irradiated common carp sperm to activate haploid gynogenetic zebrafish development. Carp × zebrafish hybrids are shown to have a characteristic set of features during embryonic development and exhibit functional development of several tissues (muscle, heart and nervous system). Hybrids become inviable past the embryonic stages. This technique eliminates the possibility of incompletely irradiated zebrafish spermatozoa contaminating haploid progenies. While developing this protocol, one unique zebrafish female was identified which, upon insemination with UV-irradiated carp spermatozoa, repeatedly displayed spontaneous diploidization of the maternal chromosomes in her offspring.

scholarly journals The miR-125 family is an important regulator of the expression and maintenance of maternal effect genes during preimplantational embryo development

Open Biology ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 160181 ◽  
Author(s):  
Kyeoung-Hwa Kim ◽  
You-Mi Seo ◽  
Eun-Young Kim ◽  
Su-Yeon Lee ◽  
Jini Kwon ◽  
...  
Keyword(s):  
Embryo Development ◽  
Maternal Effect ◽  
Early Embryo ◽  
Binding Motif ◽  
Seed Region ◽  
Maternal Effect Gene ◽  
Maternal Effect Genes ◽  
Important Regulator ◽  
Genome Activation ◽  
Zygotic Genome

Previously, we reported that Sebox is a new maternal effect gene (MEG) that is required for early embryo development beyond the two-cell (2C) stage because this gene orchestrates the expression of important genes for zygotic genome activation (ZGA). However, regulators of Sebox expression remain unknown. Therefore, the objectives of the present study were to use bioinformatics tools to identify such regulatory microRNAs (miRNAs) and to determine the effects of the identified miRNAs on Sebox expression. Using computational algorithms, we identified a motif within the 3′UTR of Sebox mRNA that is specific to the seed region of the miR-125 family, which includes miR-125a-5p, miR-125b-5p and miR-351-5p. During our search for miRNAs, we found that the Lin28a 3′UTR also contains the same binding motif for the seed region of the miR-125 family. In addition, we confirmed that Lin28a also plays a role as a MEG and affects ZGA at the 2C stage, without affecting oocyte maturation or fertilization. Thus, we provide the first report indicating that the miR-125 family plays a crucial role in regulating MEGs related to the 2C block and in regulating ZGA through methods such as affecting Sebox and Lin28a in oocytes and embryos.

scholarly journals How Zebrafish Can Drive the Future of Genetic-based Hearing and Balance Research

2021 ◽  
Author(s):  
Lavinia Sheets ◽  
Melanie Holmgren ◽  
Katie S Kindt
Keyword(s):  
Animal Models ◽  
Reverse Genetics ◽  
Genetic Model ◽  
Behavioral Changes ◽  
Reverse Genetic ◽  
Genetic Screens ◽  
Genetic Studies ◽  
Morphological Alterations ◽  
Forward Genetic Screens ◽  
Transgenic Lines

AbstractOver the last several decades, studies in humans and animal models have successfully identified numerous molecules required for hearing and balance. Many of these studies relied on unbiased forward genetic screens based on behavior or morphology to identify these molecules. Alongside forward genetic screens, reverse genetics has further driven the exploration of candidate molecules. This review provides an overview of the genetic studies that have established zebrafish as a genetic model for hearing and balance research. Further, we discuss how the unique advantages of zebrafish can be leveraged in future genetic studies. We explore strategies to design novel forward genetic screens based on morphological alterations using transgenic lines or behavioral changes following mechanical or acoustic damage. We also outline how recent advances in CRISPR-Cas9 can be applied to perform reverse genetic screens to validate large sequencing datasets. Overall, this review describes how future genetic studies in zebrafish can continue to advance our understanding of inherited and acquired hearing and balance disorders.

The Phenotype of mes-2, mes-3, mes-4 and mes-6, Maternal-Effect Genes Required for Survival of the Germline in Caenorhabditis elegans, Is Sensitive to Chromosome Dosage

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 167-185 ◽  
Author(s):  
Carol Garvin ◽  
Richard Holdeman ◽  
Susan Strome
Keyword(s):  
Gene Expression ◽  
Germ Cells ◽  
Maternal Effect ◽  
Early Embryo ◽  
Male Offspring ◽  
X Chromosomes ◽  
Control Of Gene Expression ◽  
Maternal Effect Genes ◽  
Surprising Finding

AbstractMutations in mes-2, mes-3, mes-4, and mes-6 result in maternal-effect sterility: hermaphrodite offspring of mes/mes mothers are sterile because of underproliferation and death of the germ cells, as well as an absence of gametes. Mutant germ cells do not undergo programmed cell death, but instead undergo a necrotic-type death, and their general poor health apparently prevents surviving germ cells from forming gametes. Male offspring of mes mothers display a significantly less severe germline phenotype than their hermaphrodite siblings, and males are often fertile. This differential response of hermaphrodite and male offspring to the absence of mes+ product is a result of their different X chromosome compositions; regardless of their sexual phenotype, XX worms display a more severe germline phenotype than XO worms, and XXX worms display the most severe phenotype. The sensitivity of the mutant phenotype to chromosome dosage, along with the similarity of two MES proteins to chromatin-associated regulators of gene expression in Drosophila, suggest that the essential role of the mes genes is in control of gene expression in the germline. An additional, nonessential role of the mes genes in the soma is suggested by the surprising finding that mutations in the mes genes, like mutations in dosage compensation genes, feminize animals whose male sexual identity is somewhat ambiguous. We hypothesize that the mes genes encode maternally supplied regulators of chromatin structure and gene expression in the germline and perhaps in somatic cells of the early embryo, and that at least some of their targets are on the X chromosomes.

A molecular screen for polar-localised maternal RNAs in the early embryo of Drosophila

Zygote ◽  
1993 ◽  
Vol 1 (3) ◽  
pp. 257-271 ◽  
Author(s):  
Dali Ding ◽  
Howard D. Lipshitz
Keyword(s):  
Maternal Effect ◽  
Biological Significance ◽  
Early Embryo ◽  
Early Embryogenesis ◽  
Cdna Libraries ◽  
Mitochondrial Cytochrome ◽  
Molecular Approach ◽  
Genetic Screens ◽  
Potential Use ◽  
Genetic Strategies

SummaryLocalised, maternally synthesised RNAs and proteins play an important role in an early animal embryogenesis. In Drosophila, genetic screens have recovered a number of maternal effect loci that encode localised products in the embryo. However, only a third of Drosophila's genes have been genetically mutated. Consequently, we conducted a molecular screen for polar-localised RNAs in the early Drosophila embryo in order to identify additional maternal molecules that carry out spatially restricted functions during early embryogenesis. Total RNA was purified from anterior or posterior poles cut off early Drosophila embryos. These RNAs were used to construct directionally cloned anterior and posterior cDNA libraries which were used in a differential screen for cDNAs representing maternal RNAs localised to one or other pole of the embryo. Five such clones were identified, representing cyclin B RNA, Hsp83 RNA, 28S ribosomal RNA, mitochondrial cytochrome c oxidase subunit one RNA and mitochondrial 16S large ribosomal RNA. Mutations in the loci encoding these RNAs have not been recovered in genetic screens, confirming that our molecular approach complements genetic strategies for identifying maternal molecules that carry out spatially restricted functions in the early embryo. We consider the possible biological significance of localisation of each of these species of transcripts as well as the mechanism of their localisation, and discuss the potential use of our cDNA libraries in screens for rarer localised RNAs.

A sensitized genetic screen to identify regulators of C. elegans germline stem cells

2021 ◽  
Author(s):  
Sarah Robinson-Thiewes ◽  
Aaron M. Kershner ◽  
Heaji Shin ◽  
Kimberly A. Haupt ◽  
Peggy Kroll-Connor ◽  
...  
Keyword(s):  
Stem Cells ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Gene Products ◽  
Germline Stem Cells ◽  
Loss Of Function ◽  
Genetic Screens ◽  
Self Renewal ◽  
C Elegans ◽  
Forward Genetic Screens

AbstractGermline stem cells (GSCs) in Caenorhabditis elegans are maintained by GLP-1/Notch signaling from the niche and by a downstream RNA regulatory network. Loss of the GLP-1 receptor causes GSCs to precociously undergo meiotic differentiation, the “Glp” phenotype, due to a failure to self-renew. lst-1 and sygl-1 are functionally redundant direct targets of GLP-1 signaling whose gene products work with PUF RNA binding proteins to promote GSC self-renewal. Whereas single loss-of-function mutants are fertile, lst-1 sygl-1 double mutants are sterile and Glp. We set out to identify genes that function redundantly with either lst-1 or sygl-1 to maintain GSCs. To this end, we conducted forward genetic screens for Glp mutants in genetic backgrounds lacking functional copies of either lst-1 or sygl-1. The screens generated nine glp-1 alleles, two lst-1 alleles, and one allele of pole-1, which encodes the catalytic subunit of DNA polymerase ε. Three glp-1 alleles reside in Ankyrin (ANK) repeats not previously mutated. pole-1 single mutants have a low penetrance Glp that is enhanced by loss of either lst-1 or sygl-1. Thus, the screen uncovered one locus that interacts genetically with both lst-1 and sygl-1 and generated useful mutations for further studies of GSC regulation.

scholarly journals Maternal variants in NLRP and other maternal effect proteins are associated with multilocus imprinting disturbance in offspring

2018 ◽  
Vol 55 (7) ◽  
pp. 497-504 ◽  
Author(s):  
Matthias Begemann ◽  
Faisal I Rezwan ◽  
Jasmin Beygo ◽  
Louise E Docherty ◽  
Julia Kolarova ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Maternal Effect ◽  
Pregnancy Loss ◽  
Early Embryo ◽  
Imprinting Disorders ◽  
Monozygotic Twinning ◽  
Whole Exome ◽  
Maternal Effect Genes ◽  
Mammalian Genes

BackgroundGenomic imprinting results from the resistance of germline epigenetic marks to reprogramming in the early embryo for a small number of mammalian genes. Genetic, epigenetic or environmental insults that prevent imprints from evading reprogramming may result in imprinting disorders, which impact growth, development, behaviour and metabolism. We aimed to identify genetic defects causing imprinting disorders by whole-exome sequencing in families with one or more members affected by multilocus imprinting disturbance.MethodsWhole-exome sequencing was performed in 38 pedigrees where probands had multilocus imprinting disturbance, in five of whom maternal variants in NLRP5 have previously been found.ResultsWe now report 15 further pedigrees in which offspring had disturbance of imprinting, while their mothers had rare, predicted-deleterious variants in maternal effect genes, including NLRP2, NLRP7 and PADI6. As well as clinical features of well-recognised imprinting disorders, some offspring had additional features including developmental delay, behavioural problems and discordant monozygotic twinning, while some mothers had reproductive problems including pregnancy loss.ConclusionThe identification of 20 putative maternal effect variants in 38 families affected by multilocus imprinting disorders adds to the evidence that maternal genetic factors affect oocyte fitness and thus offspring development. Testing for maternal-effect genetic variants should be considered in families affected by atypical imprinting disorders.

scholarly journals Variants in Maternal Effect Genes and Relaxed Imprinting Control in a Special Placental Mesenchymal Dysplasia Case with Mild Trophoblast Hyperplasia

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 544
Author(s):  
Tien-Chi Huang ◽  
Kung-Chao Chang ◽  
Jen-Yun Chang ◽  
Yi-Shan Tsai ◽  
Yao-Jong Yang ◽  
...  
Keyword(s):  
Maternal Effect ◽  
Hydatidiform Mole ◽  
Placental Tissue ◽  
Differentially Methylated Region ◽  
Normal Birth ◽  
Maternal Effect Genes ◽  
Common Etiology ◽  
Artificial Abortion ◽  
Secondary Dmr ◽  
Placental Mesenchymal Dysplasia

Placental mesenchymal dysplasia (PMD) and partial hydatidiform mole (PHM) placentas share similar characteristics, such as placental overgrowth and grape-like placental tissues. Distinguishing PMD from PHM is critical because the former can result in normal birth, while the latter diagnosis will lead to artificial abortion. Aneuploidy and altered dosage of imprinted gene expression are implicated in the pathogenesis of PHM and also some of the PMD cases. Diandric triploidy is the main cause of PHM, whereas mosaic diploid androgenetic cells in the placental tissue have been associated with the formation of PMD. Here, we report a very special PMD case also presenting with trophoblast hyperplasia phenotype, which is a hallmark of PHM. This PMD placenta has a normal biparental diploid karyotype and is functionally sufficient to support normal fetal growth. We took advantage of this unique case to further dissected the potential common etiology between these two diseases. We show that the differentially methylated region (DMR) at NESP55, a secondary DMR residing in the GNAS locus, is significantly hypermethylated in the PMD placenta. Furthermore, we found heterozygous mutations in NLRP2 and homozygous variants in NLRP7 in the mother’s genome. NLRP2 and NLRP7 are known maternal effect genes, and their mutation in pregnant females affects fetal development. The variants/mutations in both genes have been associated with imprinting defects in mole formation and potentially contributed to the mild abnormal imprinting observed in this case. Finally, we identified heterozygous mutations in the X-linked ATRX gene, a known maternal–zygotic imprinting regulator in the patient. Overall, our study demonstrates that PMD and PHM may share overlapping etiologies with the defective/relaxed dosage control of imprinted genes, representing two extreme ends of a spectrum.

Nutritional Status Impacts Epigenetic Regulation in Early Embryo Development: A Scoping Review

2021 ◽  
Author(s):  
Shuang Cai ◽  
Shuang Quan ◽  
Guangxin Yang ◽  
Meixia Chen ◽  
Qianhong Ye ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Embryo Development ◽  
Epigenetic Regulation ◽  
Scoping Review ◽  
Epigenetic Modification ◽  
Reproductive Technologies ◽  
Early Embryo ◽  
Epigenetic Modifications ◽  
Nutrition Status ◽  
Early Embryo Development

ABSTRACTWith the increasing maternal age and the use of assisted reproductive technology in various countries worldwide, the influence of epigenetic modification on embryonic development is increasingly notable and prominent. Epigenetic modification disorders caused by various nutritional imbalance would cause embryonic development abnormalities and even have an indelible impact on health in adulthood. In this scoping review, we summarize the main epigenetic modifications in mammals and the synergies among different epigenetic modifications, especially DNA methylation, histone acetylation, and histone methylation. We performed an in-depth analysis of the regulation of various epigenetic modifications on mammals from zygote formation to cleavage stage and blastocyst stage, and reviewed the modifications of key sites and their potential molecular mechanisms. In addition, we discuss the effects of nutrition (protein, lipids, and one-carbon metabolism) on epigenetic modification in embryos and emphasize the importance of various nutrients in embryonic development and epigenetics during pregnancy. Failures in epigenetic regulation have been implicated in mammalian and human early embryo loss and disease. With the use of reproductive technologies, it is becoming even more important to establish developmentally competent embryos. Therefore, it is essential to evaluate the extent to which embryos are sensitive to these epigenetic modifications and nutrition status. Understanding the epigenetic regulation of early embryo development will help us make better use of reproductive technologies and nutrition regulation to improve reproductive health in mammals.

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