Distribution of swallow protein in egg chambers and embryos of Drosophila melanogaster

Development ◽  
1993 ◽  
Vol 119 (2) ◽  
pp. 457-470 ◽  
Author(s):  
J. Hegde ◽  
E.C. Stephenson
Keyword(s):  
Nurse Cell ◽  
Anterior Margin ◽  
Nuclear Division ◽  
Rna Localization ◽  
Early Embryogenesis ◽  
Asymmetric Distribution ◽  
Cell Cytoplasm ◽  
Maternal Effect Gene ◽  
Egg Chambers ◽  
Effect Gene

The Drosophila maternal effect gene swallow has a role in localizing bicoid mRNA at the anterior margin of the oocyte during oogenesis, and a poorly characterized role in nuclear divisions in early embryogenesis. We have examined the distribution of swallow protein during oogenesis and embryogenesis using anti-swallow antibodies. During oogenesis, high levels of swallow protein are present in basal nurse cell cytoplasm, although small amounts are also present at the anterior oocyte margin, the site of bicoid RNA localization. Only a small fraction of swallow protein is in a position to interact directly with bicoid RNA during localization. The asymmetric distribution of swallow protein is disrupted in swallow ovaries, in which bicoid RNA becomes unlocalized late in oogenesis. swallow protein is uniformly distributed in eggs, but becomes localized to nuclei during early mitotic divisions in early embryogenesis. swallow protein enters each nucleus at the beginning of mitosis, occupies a position complementary to that of condensed chromatin, and leaves each nucleus at the end of mitosis. We show examples of nuclear division defects in swallow mutant embryos, and suggest that the abnormal nuclear divisions in early swallow embryos reflect a second function for swallow protein that contributes to abdominal segmentation defects common in swallow embryos.

scholarly journals A mutation in the zebrafish maternal-effect gene nebel affects furrow formation and vasa RNA localization

1999 ◽  
Vol 9 (24) ◽  
pp. 1431-1440 ◽  
Author(s):  
Francisco Pelegri ◽  
Holger Knaut ◽  
Hans-Martin Maischein ◽  
Stefan Schulte-Merker ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Maternal Effect ◽  
Rna Localization ◽  
Maternal Effect Gene ◽  
Effect Gene

scholarly journals Drosophila cytoplasmic dynein, a microtubule motor that is asymmetrically localized in the oocyte.

1994 ◽  
Vol 126 (6) ◽  
pp. 1475-1494 ◽  
Author(s):  
M Li ◽  
M McGrail ◽  
M Serr ◽  
T S Hays
Keyword(s):  
Heavy Chain ◽  
Maternal Effect ◽  
Nurse Cell ◽  
Cytoplasmic Dynein ◽  
Cdna Clones ◽  
Dynein Heavy Chain ◽  
Dynein Motor ◽  
Maternal Effect Gene ◽  
Microtubule Motor ◽  
Egg Chambers

The unidirectional movements of the microtubule-associated motors, dyneins, and kinesins, provide an important mechanism for the positioning of cellular organelles and molecules. An intriguing possibility is that this mechanism may underlie the directed transport and asymmetric positioning of morphogens that influence the development of multicellular embryos. In this report, we characterize the Drosophila gene, Dhc64C, that encodes a cytoplasmic dynein heavy chain polypeptide. The primary structure of the Drosophila cytoplasmic dynein heavy chain polypeptide has been determined by the isolation and sequence analysis of overlapping cDNA clones. Drosophila cytoplasmic dynein is highly similar in sequence and structure to cytoplasmic dynein isoforms reported for other organisms. The Dhc64C dynein transcript is differentially expressed during development with the highest levels being detected in the ovaries of adult females. Within the developing egg chambers of the ovary, the dynein gene is predominantly transcribed in the nurse cell complex. In contrast, the encoded dynein motor protein displays a striking accumulation in the single cell that will develop as the oocyte. The temporal and spatial pattern of dynein accumulation in the oocyte is remarkably similar to that of several maternal effect gene products that are essential for oocyte differentiation and axis specification. This distribution and its disruption by specific maternal effect mutations lends support to recent models suggesting that microtubule motors participate in the transport of these morphogens from the nurse cell cytoplasm to the oocyte.

Gas6 Is a New Candidate of Maternal Effect Gene Essential for Cytoplasmic Maturation of Oocytes and Early Embryogenesis.

2010 ◽  
Vol 83 (Suppl_1) ◽  
pp. 254-254
Author(s):  
Kyeoung-Hwa Kim ◽  
Eun-Young Kim ◽  
Hyun-Seo Lee ◽  
Eunju Kim ◽  
Kyung-Ah Lee
Keyword(s):  
Maternal Effect ◽  
Early Embryogenesis ◽  
Maternal Effect Gene ◽  
Cytoplasmic Maturation ◽  
Effect Gene

NLRP2 and FAF1 deficiency blocks early embryogenesis in the mouse

Reproduction ◽  
2017 ◽  
Vol 154 (3) ◽  
pp. 245-251 ◽  
Author(s):  
Hui Peng ◽  
Haijun Liu ◽  
Fang Liu ◽  
Yuyun Gao ◽  
Jing Chen ◽  
...  
Keyword(s):  
Specific Binding ◽  
Specific Interaction ◽  
Early Embryo ◽  
Early Embryogenesis ◽  
Preimplantation Embryos ◽  
Binding Partner ◽  
Maternal Effect Gene ◽  
Early Embryos ◽  
Embryonic Arrest ◽  
Effect Gene

Nlrp2 is a maternal effect gene specifically expressed by mouse ovaries; deletion of this gene from zygotes is known to result in early embryonic arrest. In the present study, we identified FAF1 protein as a specific binding partner of the NLRP2 protein in both mouse oocytes and preimplantation embryos. In addition to early embryos, both Faf1 mRNA and protein were detected in multiple tissues. NLRP2 and FAF1 proteins were co-localized to both the cytoplasm and nucleus during the development of oocytes and preimplantation embryos. Co-immunoprecipitation assays were used to confirm the specific interaction between NLRP2 and FAF1 proteins. Knockdown of the Nlrp2 or Faf1 gene in zygotes interfered with the formation of a NLRP2–FAF1 complex and led to developmental arrest during early embryogenesis. We therefore conclude that NLRP2 interacts with FAF1 under normal physiological conditions and that this interaction is probably essential for the successful development of cleavage-stage mouse embryos. Our data therefore indicated a potential role for NLRP2 in regulating early embryo development in the mouse.

abnormal chromatin (abc), a maternal-effect locus in Drosophila melanogaster

1991 ◽  
Vol 98 (2) ◽  
pp. 233-243 ◽  
Author(s):  
K.B. Vessey ◽  
R.L. Ludwiczak ◽  
A.S. Briot ◽  
E.M. Underwood
Keyword(s):  
Drosophila Melanogaster ◽  
Maternal Effect ◽  
Chromosome Structure ◽  
Nuclear Division ◽  
Embryonic Cell ◽  
Female Sterility ◽  
Chromosome 2 ◽  
Maternal Effect Gene ◽  
Embryonic Cell Cycle ◽  
Effect Gene

Mutations in the maternal-effect gene abnormal chromatin (abc) in Drosophila melanogaster result in a variety of defects involving nuclear replication/division. Three recessive alleles of this gene, which maps near 51F on chromosome 2, all result in female sterility. They cause slower embryonic development that is usually abnormal from the earliest nuclear divisions and arrested by the sixth one. Nuclei tend to be large and erratically distributed, some intensely staining. Mitotic asynchrony is common. Few embryos reach the gastrula stage and none hatch. With the weakest allele, fsPL, bridges between nuclei are common; abnormal chromatin clumps that resemble yolk nuclei occur before the other nuclei reach the surface; and spindle anomalies and DNA wads with numerous centrosomes are seen. Females with the stronger alleles, fsA5 and fs27, lay fewer eggs and a smaller proportion of embryos reach blastoderm; developmental arrest occurs earlier, usually with several large nuclei distributed along the length of the embryo. Chorion defects occur in all three mutants. Mitotic asynchrony, nuclear bridging, endoreduplication and nuclear behavior aberrant from the first division suggest that the abc gene product operates in DNA replication/nuclear division. Larval (homozygous F1) neuroblast chromosome structure and mitotic indices are normal, indicating that any mitotic function is strictly maternal, i.e. abc is not a general mitotic gene. Thus abc is one of a few known genes with a maternal effect that appears to function in the embryonic cell cycle.

scholarly journals Germline Cell Death Is Inhibited byP-Element Insertions Disrupting thedcp-1/pitaNested Gene Pair in Drosophila

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 1881-1888 ◽  
Author(s):  
Bonni Laundrie ◽  
Jeanne S Peterson ◽  
Jason S Baum ◽  
Jeffrey C Chang ◽  
Dana Fileppo ◽  
...  
Keyword(s):  
Cell Death ◽  
Nurse Cell ◽  
Zinc Finger Protein ◽  
P Element ◽  
Germline Cell ◽  
Developmentally Regulated ◽  
Developmental Abnormalities ◽  
Egg Chambers ◽  
Caspase Gene ◽  
Active Caspase

AbstractGermline cell death in Drosophila oogenesis is controlled by distinct signals. The death of nurse cells in late oogenesis is developmentally regulated, whereas the death of egg chambers during mid-oogenesis is induced by environmental stress or developmental abnormalities. P-element insertions in the caspase gene dcp-1 disrupt both dcp-1 and the outlying gene, pita, leading to lethality and defective nurse cell death in late oogenesis. By isolating single mutations in the two genes, we have found that the loss of both genes contributes to this ovary phenotype. Mutants of pita, which encodes a C2H2 zinc-finger protein, are homozygous lethal and show dumpless egg chambers and premature nurse cell death in germline clones. Early nurse cell death is not observed in the dcp-1/pita double mutants, suggesting that dcp-1+ activity is required for the mid-oogenesis cell death seen in pita mutants. dcp-1 mutants are viable and nurse cell death in late oogenesis occurs normally. However, starvation-induced germline cell death during mid-oogenesis is blocked, leading to a reduction and inappropriate nuclear localization of the active caspase Drice. These findings suggest that the combinatorial loss of pita and dcp-1 leads to the increased survival of abnormal egg chambers in mutants bearing the P-element alleles and that dcp-1 is essential for cell death during mid-oogenesis.

Evidence against electrophoresis as the principal mode of protein transport in vitellogenic ovarian follicles of Drosophila

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 279-288
Author(s):  
J. Bohrmann ◽  
H. Gutzeit
Keyword(s):  
Nurse Cell ◽  
Protein Transport ◽  
Exchange Chromatography ◽  
Heterologous Proteins ◽  
Nurse Cells ◽  
Cell Cytoplasm ◽  
Two Dimensional Gel Electrophoresis ◽  
Electrophoretic Transport ◽  
Indicator Dyes

Charged cell constituents in polytrophic insect follicles are thought to be transported in the nurse cell-oocyte syncytium by way of electrophoresis. This concept, proposed by Woodruff & Telfer (1980) was based on electrophysiological data and microinjection of heterologous proteins using Hyalophora follicles. By microinjecting fluorescently labelled acidic and basic proteins into the nurse cells or oocyte of vitellogenic Drosophila follicles, we failed to obtain evidence for charge-dependent migration of these molecules. We have also analyzed the proteins of nurse cells and oocyte on isoelectric focusing gels, by means of two-dimensional gel electrophoresis, and by ion exchange chromatography to see if basic or acidic proteins accumulate in vivo in nurse cells and oocyte, respectively. For the bulk of the follicular proteins we found no accumulation. Further evidence against an electrophoretic transport system in Drosophila was obtained by estimating the intracellular pH from the colour of indicator dyes microinjected into the follicles; the results indicate that the pH in the nurse cell cytoplasm is lower than that in the ooplasm. According to the model developed for Hyalophora, electrophoretic transport would be favoured by high pH in the nurse cell cytoplasm.

scholarly journals Zebrafish vasa RNA but Not Its Protein Is a Component of the Germ Plasm and Segregates Asymmetrically before Germline Specification

2000 ◽  
Vol 149 (4) ◽  
pp. 875-888 ◽  
Author(s):  
Holger Knaut ◽  
Francisco Pelegri ◽  
Kerstin Bohmann ◽  
Heinz Schwarz ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Germ Cell ◽  
Germ Plasm ◽  
Primordial Germ Cell ◽  
Subcellular Structure ◽  
Actin Cortex ◽  
Maternal Effect Gene ◽  
Close Proximity ◽  
Hybrid Fish ◽  
Vasa Gene ◽  
Effect Gene

Work in different organisms revealed that the vasa gene product is essential for germline specification. Here, we describe the asymmetric segregation of zebrafish vasa RNA, which distinguishes germ cell precursors from somatic cells in cleavage stage embryos. At the late blastula (sphere) stage, vasa mRNA segregation changes from asymmetric to symmetric, a process that precedes primordial germ cell proliferation and perinuclear localization of Vasa protein. Analysis of hybrid fish between Danio rerio and Danio feegradei demonstrates that zygotic vasa transcription is initiated shortly after the loss of unequal vasa mRNA segregation. Blocking DNA replication indicates that the change in vasa RNA segregation is dependent on a maternal program. Asymmetric segregation is impaired in embryos mutant for the maternal effect gene nebel. Furthermore, ultrastructural analysis of vasa RNA particles reveals that vasa RNA, but not Vasa protein, localizes to a subcellular structure that resembles nuage, a germ plasm organelle. The structure is initially associated with the actin cortex, and subsequent aggregation is inhibited by actin depolymerization. Later, the structure is found in close proximity of microtubules. We previously showed that its translocation to the distal furrows is microtubule dependent. We propose that vasa RNA but not Vasa protein is a component of the zebrafish germ plasm. Triggered by maternal signals, the pattern of germ plasm segregation changes, which results in the expression of primordial germ cell–specific genes such as vasa and, consequently, in germline fate commitment.

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