Dictyate Oocytes of a Kangaroo (Macropus robustus) Show Paternal Inactivation at the X-linked Gpd Locus

1985 ◽  
Vol 38 (1) ◽  
pp. 79 ◽  
Author(s):  
PG Johnston ◽  
E S Robinson ◽  
DM Johnston
Keyword(s):  
Paternal Allele ◽  
Maternal Allele ◽  
Large Numbers ◽  
The Cross ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Medullary Cells

Purified samples of large numbers of dictyate oocytes from 13 M. robustus pouch young heterozygous for glucose-6-phosphate dehydrogenase type and six homozygous controls were examined electrophoretically to determine activity states at the Gpd locus. Like somatic cortical and medullary cells, oocytes expressed only the maternal phenotype irrespective of the direction of the cross. No evidence was found of reactivation of the inactive (paternal) allele or inactivation of both maternal and paternal alleles. It was therefore concluded that unlike eutherian dictyate oocytes, only a single (maternal) allele is active in each dictyate oocyte in M. robustus. The stage of reactivation of the paternal allele remains to be determined.

scholarly journals DNA demethylase ROS1 negatively regulates the imprinting of DOGL4 and seed dormancy in Arabidopsis thaliana

2018 ◽  
Vol 115 (42) ◽  
pp. E9962-E9970 ◽  
Author(s):  
Haifeng Zhu ◽  
Wenxiang Xie ◽  
Dachao Xu ◽  
Daisuke Miki ◽  
Kai Tang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Seed Dormancy ◽  
Genomic Imprinting ◽  
Dna Demethylation ◽  
Paternal Allele ◽  
Maternal Allele ◽  
Imprinted Gene ◽  
Differential Gene ◽  
Parent Of Origin ◽  
Dna Demethylase

Genomic imprinting is a form of epigenetic regulation resulting in differential gene expression that reflects the parent of origin. In plants, imprinted gene expression predominantly occurs in the seed endosperm. Maternal-specific DNA demethylation by the DNA demethylase DME frequently underlies genomic imprinting in endosperm. Whether other more ubiquitously expressed DNA demethylases regulate imprinting is unknown. Here, we found that the DNA demethylase ROS1 regulates the imprinting of DOGL4. DOGL4 is expressed from the maternal allele in endosperm and displays preferential methylation and suppression of the paternal allele. We found that ROS1 negatively regulates imprinting by demethylating the paternal allele, preventing its hypermethylation and complete silencing. Furthermore, we found that DOGL4 negatively affects seed dormancy and response to the phytohormone abscisic acid and that ROS1 controls these processes by regulating DOGL4. Our results reveal roles for ROS1 in mitigating imprinted gene expression and regulating seed dormancy.

scholarly journals Allelic H3K27me3 to allelic DNA methylation switch maintains noncanonical imprinting in extraembryonic cells

2019 ◽  
Vol 5 (12) ◽  
pp. eaay7246 ◽  
Author(s):  
Zhiyuan Chen ◽  
Qiangzong Yin ◽  
Azusa Inoue ◽  
Chunxia Zhang ◽  
Yi Zhang
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Genetic Manipulation ◽  
Paternal Allele ◽  
Gene Promoters ◽  
Maternal Allele ◽  
Mammalian Development ◽  
Placental Development ◽  
Early Embryos ◽  
Allele Specific

Faithful maintenance of genomic imprinting is essential for mammalian development. While germline DNA methylation–dependent (canonical) imprinting is relatively stable during development, the recently found oocyte-derived H3K27me3-mediated noncanonical imprinting is mostly transient in early embryos, with some genes important for placental development maintaining imprinted expression in the extraembryonic lineage. How these noncanonical imprinted genes maintain their extraembryonic-specific imprinting is unknown. Here, we report that maintenance of noncanonical imprinting requires maternal allele–specific de novo DNA methylation [i.e., somatic differentially methylated regions (DMRs)] at implantation. The somatic DMRs are located at the gene promoters, with paternal allele–specific H3K4me3 established during preimplantation development. Genetic manipulation revealed that both maternal EED and zygotic DNMT3A/3B are required for establishing somatic DMRs and maintaining noncanonical imprinting. Thus, our study not only reveals the mechanism underlying noncanonical imprinting maintenance but also sheds light on how histone modifications in oocytes may shape somatic DMRs in postimplantation embryos.

scholarly journals Glucose-metabolizing Enzymes of the Mouse Erythrocyte: Activity Changes During Stress Erythropoiesis

Blood ◽  
1972 ◽  
Vol 39 (4) ◽  
pp. 542-553 ◽  
Author(s):  
John J. Hutton
Keyword(s):  
Triosephosphate Isomerase ◽  
Rank Order ◽  
Inbred Mouse ◽  
Inbred Strains ◽  
Enzymatic Activities ◽  
Phosphoglycerate Mutase ◽  
Metabolizing Enzymes ◽  
Stress Erythropoiesis ◽  
Large Numbers ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract Many features of normal and abnormal erythropoiesis have been described in the inbred mouse, but no systematic studies of enzymatic activities in mouse erythrocytes have been reported. The activities of 14 enzymes of glycolysis and the hexose monophosphate shunt have been measured in mouse erythrocytes formed under normal conditions and during hemopoietic stress induced by phenylhydrazine treatment. The responses of inbred strains A/J and C57L/J were compared. In normal cells of each strain the activity of hexokinase was lowest, that of triosephosphate isomerase the highest, and the rank order of other enzymatic activities in the mouse was similar to that reported for the human erythrocyte. All enzymatic activities increased during the reticulocytosis accompanying stress erythropoiesis, with phosphofructokinase, aldolase, phosphoglycerate mutase, and glucose 6-phosphate dehydrogenase (G6-PD) showing the greatest relative elevations. Enzymatic activities declined rapidly during the 2-wk period following the initial reticulocytosis, suggesting that large numbers of immature erythrocytes with high enzymatic activities and shortened life spans had been produced during the response to erythropoietic stress. In normal hemolysates heated at 50°C, the most labile enzymes were glucose 6-phosphate dehydrogenase, enolase, and glyceraldehyde phosphate dehydrogenase. In the presence of erythrocyte stromata, glucose 6-phosphate dehydrogenase was more thermolabile in hemolysates of strain C57L/J than in those of A/J. This difference correlates both with the markedly lower activity of G6-PD in normal erythrocytes of C57L/J mice compared to erythrocytes of A/J mice and with the more rapid decrease in G6-PD dehydrogenase activity in aging erythrocytes of C57L/J.

scholarly journals Single Nucleotide Primer Extension (SNuPE) analysis of the G6PD gene in somatic cells and oocytes of a kangaroo (Macropus robustus)

2000 ◽  
Vol 75 (3) ◽  
pp. 269-274 ◽  
Author(s):  
DEBBIE WATSON ◽  
ANITA S. JACOMBS ◽  
DAVID A. LOEBEL ◽  
EDWARD S. ROBINSON ◽  
PETER G. JOHNSTON
Keyword(s):  
Somatic Cells ◽  
Primer Extension ◽  
Paternal Allele ◽  
Transcriptional Level ◽  
Specific Expression ◽  
Single Nucleotide ◽  
Cultured Fibroblasts ◽  
Preferential Expression ◽  
Single Nucleotide Primer Extension ◽  
Glucose 6 Phosphate Dehydrogenase

cDNA sequence analysis of the X-linked glucose-6-phosphate dehydrogenase (G6PD) gene has shown a base difference between two subspecies of the kangaroo, Macropus robustus robustus (wallaroo) and M. r. erubescens (euro). A thymine residue in the wallaroo at position 358 in exon 5 has been replaced by a cytosine residue in the euro, which accounts for the previously reported electrophoretic difference between the two subspecies. This base difference allowed use of the Single Nucleotide Primer Extension (SNuPE) technique to study allele-specific expression of G6PD at the transcriptional level. We began by examining G6PD expression in somatic cells and observed complete paternal X inactivation in all somatic tissues of adult female heterozygotes, whereas we found partial paternal allele activity in cultured fibroblasts, thus confirming previous allozyme electrophoresis studies. In late dictyate oocytes from an adult heterozygote, the assay also detected expression of both the maternal and paternal alleles at the G6PD locus, with the maternal allele showing preferential expression. Thus reactivation of the inactive paternally derived X chromosome occurs during oogenesis in M. robustus, although the exact timing of reactivation remains to be determined.

scholarly journals BIOLOGICAL SCIENCES: Genetics

2018 ◽  
Author(s):  
Jack S. Hsiao ◽  
Noelle D. Germain ◽  
Andrea Wilderman ◽  
Christopher Stoddard ◽  
Luke A. Wojenski ◽  
...  
Keyword(s):  
Boundary Element ◽  
Angelman Syndrome ◽  
Antisense Transcript ◽  
Neurodevelopmental Disorder ◽  
Boundary Function ◽  
Paternal Allele ◽  
Loss Of Function ◽  
Maternal Allele ◽  
Specific Expression ◽  
Human Neurons

ABSTRACTAngelman syndrome (AS) is a severe neurodevelopmental disorder caused by the loss of function from the maternal allele of UBE3A, a gene encoding an E3 ubiquitin ligase. UBE3A is only expressed from the maternally-inherited allele in mature human neurons due to tissue-specific genomic imprinting. Imprinted expression of UBE3A is restricted to neurons by expression of UBE3A antisense transcript (UBE3A-ATS) from the paternally-inherited allele, which silences the paternal allele of UBE3A in cis. However, the mechanism restricting UBE3A-ATS expression and UBE3A imprinting to neurons is not understood. We used CRISPR/Cas9-mediated genome editing to functionally define a bipartite boundary element critical for neuron-specific expression of UBE3A-ATS in humans. Removal of this element led to upregulation of UBE3A-ATS without repressing paternal UBE3A. However, increasing expression of UBE3A-ATS in the absence of the boundary element resulted in full repression of paternal UBE3A, demonstrating that UBE3A imprinting requires both the loss of function from the boundary element as well as upregulation of UBE3A-ATS. These results suggest that manipulation of the competition between UBE3A-ATS and UBE3A may provide a potential therapeutic approach for AS.SIGNIFICANCE STATEMENTAngelman syndrome is a neurodevelopmental disorder caused by loss of function from the maternal allele of UBE3A, an imprinted gene. The paternal allele of UBE3A is silenced by a long, non-coding antisense transcript in mature neurons. We have identified a boundary element that stops the transcription of the antisense transcript in human pluripotent stem cells, and thus restricts UBE3A imprinted expression to neurons. We further determined that UBE3A imprinting requires both the loss of the boundary function and sufficient expression of the antisense transcript to silence paternal UBE3A. These findings provide essential details about the mechanisms of UBE3A imprinting that may suggest additional therapeutic approaches for Angelman syndrome.

Search for Counterparties

Dark Markets ◽  
2012 ◽  
Author(s):  
Darrell Duffie
Keyword(s):  
Discrete Time ◽  
Continuous Time ◽  
Law Of Large Numbers ◽  
Random Matching ◽  
Cross Sectional ◽  
Equilibrium Search ◽  
Search Intensity ◽  
Large Numbers ◽  
The Law ◽  
The Cross

This chapter introduces the modeling of search and random matching in large economies. The objective is to build intuition and techniques for later chapters. After some mathematical prerequisites, it defines the notion of random matching. It then invokes the law of large numbers to calculate the cross-sectional distribution of types of matches. This is extended to multiperiod search, first in discrete-time settings and then in continuous time. The optimal search intensity of a given agent, given the cross-sectional distribution of types in the population, is characterized with Bellman's principle. The chapter then briefly takes up the issue of equilibrium search efforts.

scholarly journals Angelman syndrome imprinting center encodes a transcriptional promoter

2014 ◽  
Vol 112 (22) ◽  
pp. 6871-6875 ◽  
Author(s):  
Michael W. Lewis ◽  
Jason O. Brant ◽  
Joseph M. Kramer ◽  
James I. Moss ◽  
Thomas P. Yang ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Angelman Syndrome ◽  
Paternal Allele ◽  
Specific Gene ◽  
Prader Willi Syndrome ◽  
Maternal Allele ◽  
Expression Of Genes ◽  
Imprinting Center ◽  
Maternal Contribution ◽  
Parent Of Origin

Clusters of imprinted genes are often controlled by an imprinting center that is necessary for allele-specific gene expression and to reprogram parent-of-origin information between generations. An imprinted domain at 15q11–q13 is responsible for both Angelman syndrome (AS) and Prader–Willi syndrome (PWS), two clinically distinct neurodevelopmental disorders. Angelman syndrome arises from the lack of maternal contribution from the locus, whereas Prader–Willi syndrome results from the absence of paternally expressed genes. In some rare cases of PWS and AS, small deletions may lead to incorrect parent-of-origin allele identity. DNA sequences common to these deletions define a bipartite imprinting center for the AS–PWS locus. The PWS–smallest region of deletion overlap (SRO) element of the imprinting center activates expression of genes from the paternal allele. The AS–SRO element generates maternal allele identity by epigenetically inactivating the PWS–SRO in oocytes so that paternal genes are silenced on the future maternal allele. Here we have investigated functional activities of the AS–SRO, the element necessary for maternal allele identity. We find that, in humans, the AS–SRO is an oocyte-specific promoter that generates transcripts that transit the PWS–SRO. Similar upstream promoters were detected in bovine oocytes. This result is consistent with a model in which imprinting centers become DNA methylated and acquire maternal allele identity in oocytes in response to transiting transcription.

Interface and twins in GaAs/Si grown by both MBE And MOCVD

1990 ◽  
Vol 48 (4) ◽  
pp. 468-469
Author(s):  
Rongtuan Fan
Keyword(s):  
Phase Transformation ◽  
Liquid Nitrogen ◽  
Systematic Difference ◽  
Plane Section ◽  
Lattice Period ◽  
Cross Sectional ◽  
Weak Beam ◽  
Large Numbers ◽  
Twinning Plane ◽  
The Cross

Recently, A number of the scientists have studied GaAs/si In this work, we intend to investigateo the interface and the twins in GaAs/Si which was grown by both MBE and MOCVD. TEM studies were performed on (011) crosssections of the GaAs/Si using TEM and HREM. TEM specimens were produced by sandwiching, dimpling, and atom- milling with ˜5KV Ar ions at liquid nitrogen temperatures.It showed the cross-sectional images in GaAs/Si in Fig.la, there were a lot of defects in the interface of GaAs/Si. Fig.lb obtained using the weak beam tecnique have showed the distribution of the twins and the defects to same interface of Fig.la. As well known,in the process of growth, deformation and phase transformation for crystals, it is not only often to produce the twins, but also the twins will be continuously produced in the twins, called secondary twins. If the phenomenon which continued to produce twins in the twins would be sustained by many times, then called trine, quaternary and multiple twins boundary will emerge from the interface. In the deformation, the twins on two difference twins plane intersect with each other in move, so that, the secondary twins may be produced in the crossing section, see Fig.1b and 2. It is interesting to compare epilayers grown by MOCVD and MBE, that reveals a systematic difference between the twinning produced by the two processes.MBE growth results in very large numbers of microtwins ˜50 Å -100 Å in width in the first 1000Å or so of the layer. MOCVD tends to generate much smaller numbers of large twins (up to 1.5μ) which can penetrate right through a thick (>10μm) epilayer, Fig.1. But, by way of exception, in our research in this year, the dislocations in GaAs/Si were observed only, there was nothing for twins, Fig.3.These twins grow up in {111} , i . e . , {111} is twinning plane, section direction <112>. microtwins with 3 times that of a lattice period(Fig.4).

Single Nucleotide Polymorphisms Influence the Phenotype of Mutations P618A and R1336W found in the ADAMTS13 Gene of Congenital TTP Patients.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2977-2977
Author(s):  
Barbara Plaimauer ◽  
Gabriele Mohr ◽  
Waltraud Wernhart ◽  
Katharina Bruno ◽  
Gerhard Antoine ◽  
...  
Keyword(s):  
Amino Acid ◽  
Single Nucleotide Polymorphisms ◽  
Single Amino Acid ◽  
Paternal Allele ◽  
Amino Acid Substitutions ◽  
Common Snps ◽  
Nucleotide Polymorphisms ◽  
Adamts13 Activity ◽  
Maternal Allele ◽  
Single Nucleotide

Abstract ADAMTS13 cleaves plasmatic von Willebrand factor (VWF) between Tyr1605 and Met1606 and regulates thereby the hemostatic activity of VWF. Mutations in the ADAMTS13 gene leading to severe ADAMTS13 deficiency have been found in patients with congenital thrombotic thrombocytopenic purpura (TTP). We have analyzed the ADAMTS13 gene defects in two brothers with hereditary TTP [Antoine et al, Brit. J. Hematol., 2003] where we detected a total of six nucleotide exchanges causing point mutations. On the maternal allele we found an accumulation of five amino acid substitutions (R7W, Q448E, P618A, A732V, R1336W) and on the paternal allele a stop mutation (Q44X) leading to premature protein termination in the propeptide region. Both brothers were double heterozygotes with < 3% of ADAMTS13 activity, whereas their asymptomatic parents have ~ 50% activity. Four (R7W, Q448E, P618A, A732V) of the five maternal mutations constitute single nucleotide polymorphisms (SNP) but R1336W was identified as novel rare mutation in the second cub domain. To evaluate the biologic phenotype of a given haplotype, e.g. the functional significance of the presence of the various SNPs, we analyzed the functional impact of the individual mutations on ADAMTS13 antigen levels and ADAMTS13 activity. A series of mutant ADAMTS13 molecules was expressed which contained either single amino acid substitutions or combinations of mutations with each other. We found that the common SNPs R7W, Q448E and A732V, as single mutations, had either no or only a minor impact on ADAMTS13 secretion and ADAMTS13 activity, whereas P618A and R1336W conferred a dominant adverse effect on ADAMTS13 secretion levels. Co-expression of SNPs R7W or Q448E with SNP P618A lead to improved ADAMTS13 secretion levels and could therefore partly attenuate the detrimental effect of P618A. Concomitant expression of all four SNPs reconstituted secretion levels similar to wild-type implicating a complex synergistically interaction of SNPs located in different ADAMTS13 domain regions, however, functional activity was impaired to 50%. Mutation R1336W was shown to be, as a single amino acid exchange, responsible for reduced ADAMTS13 antigen levels, but in contrast to P618A, the negative effect of R1336W was rather enhanced by the co-expression of R7W and Q448E, than rescued, leading to the total absence of ADAMTS13 secretion from the maternal allele. Our findings provide for the first time evidence that fairly common SNPs, dependent on the presence or absence of other mutations, may differently modulate functional ADAMTS13 protease levels.

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