Restoration of the capacity to form pole cells in u.v.-irradiated Drosophila embryos

Development ◽  
1975 ◽  
Vol 33 (4) ◽  
pp. 1003-1011
Author(s):  
Richard Warn
Keyword(s):  
Pole Cell ◽  
Pole Cells ◽  
Pole Plasm ◽  
Cell Fragments ◽  
Drosophila Embryos

Injection of pole plasm into u.v.-irradiated posterior poles of early Drosophila embryos leads to the restoration of the capacity to form pole cells in nearly half of the recipients. The effect is specific, since cytoplasm from the anterior tip has no such result. In most cases only a small number (between 1 and 5) of discrete pole cells are formed. However, a large number of pole cell fragments with or without nuclei occur. Occasionally pole cells were formed outside the area of the originally irradiated pole plasm. This happened when material was injected more anteriorly than usual. Thus polar cytoplasm contains some factor(s) necessary for the formation of pole cells.

Spatial and developmental changes in the respiratory activity of mitochondria in early Drosophila embryos

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 1175-1182 ◽  
Author(s):  
T. Akiyama ◽  
M. Okada
Keyword(s):  
Respiratory Activity ◽  
Cell Formation ◽  
Rhodamine 123 ◽  
Mitochondrial Activity ◽  
Early Cleavage ◽  
Pole Cell ◽  
Posterior Group ◽  
Cleavage Stages ◽  
Pole Cells ◽  
Drosophila Embryos

Mitochondria of early Drosophila embryos were observed with a transmission electron microscope and a fluorescent microscope after vital staining with rhodamine 123, which accumulates only in active mitochondria. Rhodamine 123 accumulated particularly in the posterior pole region in early cleavage embryos, whereas the spatial distribution of mitochondria in an embryo was uniform throughout cleavage stages. In late cleavage stages, the dye showed very weak and uniform accumulation in all regions of periplasm. Polar plasm, sequestered in pole cells, restored the ability to accumulate the dye. Therefore, it is concluded that the respiratory activity of mitochondria is higher in the polar plasm than in the other regions of periplasm in early embryos, and this changes during development. The temporal changes in rhodamine 123-staining of polar plasm were not affected by u.v. irradiation at the posterior of early cleavage embryos at a sufficient dosage to prevent pole cell formation. This suggests that the inhibition of pole cell formation by u.v. irradiation is not due to the inactivation of the respiratory activities of mitochondria. In addition, we found that the anterior of Bicaudal-D mutant embryos at cleavage stage was stained with rhodamine 123 with the same intensity as the posterior of wild-type embryos. No pole cells form in the anterior of Bic-D embryos, where no restoration of mitochondrial activity occurs in the blastoderm stage. The posterior group mutations that we tested (staufen, oskar, tudor, nanos) and the terminal mutation (torso) did not alter staining pattern of the posterior with rhodamine 123.

scholarly journals Three distinct distributions of F-actin occur during the divisions of polar surface caps to produce pole cells in Drosophila embryos.

1985 ◽  
Vol 100 (4) ◽  
pp. 1010-1015 ◽  
Author(s):  
R M Warn ◽  
L Smith ◽  
A Warn
Keyword(s):  
Cell Formation ◽  
Contractile Ring ◽  
Polar Surface ◽  
Ring Type ◽  
Actin Organization ◽  
Polar Caps ◽  
Pole Cell ◽  
Nuclear Cycle ◽  
Pole Cells ◽  
Drosophila Embryos

The F-actin distribution was studied during pole cell formation in Drosophila embryos using the phalloidin derivative rhodaminyl-lysine-phallotoxin. Nuclei were also stained with 4'-6 diamidine-2-phenylindole dihydrochloride to correlate the pattern seen with the nuclear cycle. The precursors of the pole cells, the polar surface caps, were found to have an F-actin-rich cortex distinct from that of the rest of the embryo surface and an interior cytoplasm that was less intensely stained but brighter than the cytoplasm deeper in the embryo. They were found to divide once without forming true cells and then a second time when cells formed as a result of a meridional and a basal cleavage. Three distinct distributions of the cortical F-actin have been identified during these cleavages. It is concluded that the first division, which cleaves the polar caps but does not separate them from the embryo, involves very different processes from those that lead to the formation of the pole cells. A contractile-ring type of F-actin organization may not be present during the first cleavage but is suggested to occur during the second.

Polar granules and pole cells in the embryo of Calliphora erythrocephala: ultrastructure and [3H]leucine labelling

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 79-93
Author(s):  
Anders Lundquist ◽  
Hadar Emanuelsson
Keyword(s):  
Cell Formation ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Calliphora Erythrocephala ◽  
Pole Cell ◽  
Polar Granules ◽  
Pole Cells ◽  
Autoradiographic Analysis ◽  
Pole Plasm ◽  
Blastoderm Stage

The polar granules in Calliphora undergo a gradual fragmentation during early cleavage, but reaggregate after pole-cell formation. Autoradiographic analysis showed that the pole cells in Calliphora acquire a higher ‘3H’leucine label than the rest of the embryo during the blastoderm stage. Such an increased label was not seen in the pole plasm before pole-cell formation or in the pole cells during gastrulation. Electron microscopic autoradiography revealed that the polar granules are substantially labelled during the blastoderm stage. At the same time, characteristic nuclear blebs appear in the pole cells. The observations are consistent with the hypothesis that polar granules contain maternalmessenger RNA, which is released and translated into proteins.

Centrosomes, and not nuclei, initiate pole cell formation in Drosophila embryos

Cell ◽  
1989 ◽  
Vol 57 (4) ◽  
pp. 611-619 ◽  
Author(s):  
Jordan W. Raff ◽  
David M. Glover
Keyword(s):  
Cell Formation ◽  
Pole Cell ◽  
Drosophila Embryos

scholarly journals Identification of a component of Drosophila polar granules

Development ◽  
1988 ◽  
Vol 103 (4) ◽  
pp. 625-640 ◽  
Author(s):  
B. Hay ◽  
L. Ackerman ◽  
S. Barbel ◽  
L.Y. Jan ◽  
Y.N. Jan
Keyword(s):  
Germ Line ◽  
Posterior Pole ◽  
Nuclear Bodies ◽  
Maternal Origin ◽  
Pole Cell ◽  
Polar Granules ◽  
Early Embryos ◽  
Biochemical Studies ◽  
Males And Females ◽  
Pole Cells

Information necessary for the formation of pole cells, precursors of the germ line, is provided maternally and localized to the posterior pole of the Drosophila egg. The maternal origin and posterior localization of polar granules suggest that they may be associated with pole cell determinants. We have generated an antibody (Mab46F11) against polar granules. In oocytes and early embryos, the Mab46F11 antigen is sharply localized to the posterior embryonic pole. In pole cells, it becomes associated with nuclear bodies within, and nuage around, the nucleus. Immunoreactivity remains associated with cells of the germ line throughout the life cycle of both males and females. This antibody recognizes a 72–74 × 10(3) Mr protein and is useful both as a pole lineage marker and in biochemical studies of polar granules.

Oskar anchoring restricts pole plasm formation to the posterior of the Drosophila oocyte

Development ◽  
2002 ◽  
Vol 129 (15) ◽  
pp. 3705-3714 ◽  
Author(s):  
Nathalie F. Vanzo ◽  
Anne Ephrussi
Keyword(s):  
Drosophila Melanogaster ◽  
Translational Control ◽  
Cell Formation ◽  
Positional Information ◽  
Mrna Localization ◽  
Posterior Pole ◽  
Tight Coupling ◽  
Anteroposterior Patterning ◽  
Pole Cell ◽  
Pole Plasm

Localization of the maternal determinant Oskar at the posterior pole of Drosophila melanogaster oocyte provides the positional information for pole plasm formation. Spatial control of Oskar expression is achieved through the tight coupling of mRNA localization to translational control, such that only posterior-localized oskar mRNA is translated, producing the two Oskar isoforms Long Osk and Short Osk. We present evidence that this coupling is not sufficient to restrict Oskar to the posterior pole of the oocyte. We show that Long Osk anchors both oskar mRNA and Short Osk, the isoform active in pole plasm assembly, at the posterior pole. In the absence of anchoring by Long Osk, Short Osk disperses into the bulk cytoplasm during late oogenesis, impairing pole cell formation in the embryo. In addition, the pool of untethered Short Osk causes anteroposterior patterning defects, owing to the dispersion of pole plasm and its abdomen-inducing activity throughout the oocyte. We show that the N-terminal extension of Long Osk is necessary but not sufficient for posterior anchoring, arguing for multiple docking elements in Oskar. This study reveals cortical anchoring of the posterior determinant Oskar as a crucial step in pole plasm assembly and restriction, required for proper development of Drosophila melanogaster.

A single cell approach to problems of cell lineage and commitment during embryogenesis of Drosophila melanogaster

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 1-12 ◽  
Author(s):  
G.M. Technau
Keyword(s):  
Drosophila Melanogaster ◽  
Single Cell ◽  
Cell Lineage ◽  
Cellular Level ◽  
Central Importance ◽  
Cell Level ◽  
Combined Application ◽  
A Cell ◽  
Pole Cells ◽  
Drosophila Embryos

The mechanisms leading to the commitment of a cell to a particular fate or to restrictions in its developmental potencies represent a problem of central importance in developmental biology. Both at the genetic and at the molecular level, studies addressing this topic using the fruitfly Drosophila melanogaster have advanced substantially, whereas, at the cellular level, experimental techniques have been most successfully applied to organisms composed of relatively large and accessible cells. The combined application of the different approaches to one system should improve our understanding of the process of commitment as a whole. Recently, a method has been devised to study cell lineage in Drosophila embryos at the single cell level. This method has been used to analyse the lineages, as well as the state of commitment of single cell progenitors from various ectodermal, mesodermal and endodermal anlagen and of the pole cells. The results obtained from a clonal analysis of wild-type larval structures are discussed in this review.

Epsilon granules in Drosophila pole cells and oöcytes

Development ◽  
1965 ◽  
Vol 13 (1) ◽  
pp. 73-81
Author(s):  
Suzanne L. Ullmann
Keyword(s):  
Germ Cells ◽  
Microscope Study ◽  
Light Microscope ◽  
Primordial Germ Cells ◽  
Structural Level ◽  
Developmental Morphology ◽  
Insect Eggs ◽  
Polar Granules ◽  
Pole Cells ◽  
Drosophila Embryos

In many insect eggs, including those of the Diptera, deeply staining granules, rich in RNA, occur in the posterior polar plasm and during ontogeny become enclosed within the pole cells. The structure and fate of these cells, which generally give rise to the primordial germ cells, and their inclusions have excited interest for over half a century (Hegner, 1908; Huettner, 1923; Rabinowitz, 1941; Poulson, 1947; Counce, 1963; Mahowald, 1962), yet numerous questions concerning them remain unsettled or controversial to this day. For instance, the dual fate of the pole cells in Drosophila, the genus which has been most extensively studied, is still debated (Poulson & Waterhouse, 1960; Hathaway & Selman, 1961). Recently, Counce (1963), in a light-microscope study, has described the developmental morphology of the polar granules in several species of Drosophila embryos; while Mahowald (1962) has succeeded in identifying them in D. melanogaster at the ultra-structural level.

scholarly journals A small sequence in domain v of the mitochondrial large ribosomal RNA restores Drosophila melanogaster pole cell determination in uv-irradiated embryos

2010 ◽  
Vol 15 (3) ◽  
Author(s):  
Rossana Psaila ◽  
Donatella Ponti ◽  
Marta Ponzi ◽  
Franca Gigliani ◽  
Piero Battaglia
Keyword(s):  
Ribosomal Rna ◽  
Luciferase Activity ◽  
Protein Biosynthesis ◽  
Base Sequence ◽  
Cell Determination ◽  
Pole Cell ◽  
Higher Eukaryotes ◽  
Domain V ◽  
Drosophila Embryos

AbstractThe mechanism by which the mitochondrial large rRNA is involved in the restoration of the pole cell-forming ability in Drosophila embryos is still unknown. We identified a 15-ribonucleotide sequence which is conserved from the protobacterium Wolbachia to the higher eukaryotes in domain V of the mitochondrial large rRNA. This short sequence is sufficient to restore pole cell determination in UV-irradiated Drosophila embryos. Here, we provide evidence that the conserved 15-base sequence is sufficient to restore luciferase activity in vitro. Moreover, we show that the internal GAGA sequence is involved in protein binding and that mutations in this tetranucleotide affect the sequence’s ability to restore luciferase activity. The obtained results lead us to propose that mtlrRNA may be involved either in damaged protein reactivation or in protein biosynthesis during pole cell determination.

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