scholarly journals Control of lateral migration and germ cell elimination by the Drosophila melanogaster lipid phosphate phosphatases Wunen and Wunen 2

2005 ◽  
Vol 171 (4) ◽  
pp. 675-683 ◽  
Author(s):  
Hiroko Sano ◽  
Andrew D. Renault ◽  
Ruth Lehmann
Keyword(s):  
Drosophila Melanogaster ◽  
Axon Guidance ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Lateral Migration ◽  
Migration Process ◽  
The Central Nervous System ◽  
Lipid Phosphate ◽  
Lipid Phosphate Phosphatases ◽  
Single Cluster

In most organisms, primordial germ cells (PGCs) arise far from the region where somatic gonadal precursors (SGPs) are specified. Although PGCs in general originate as a single cluster of cells, the somatic parts of the gonad form on each site of the embryo. Thus, to reach the gonad, PGCs not only migrate from their site of origin but also split into two groups. Taking advantage of high-resolution real-time imaging, we show that in Drosophila melanogaster PGCs are polarized and migrate directionally toward the SGPs, avoiding the midline. Unexpectedly, neither PGC attractants synthesized in the SGPs nor known midline repellents for axon guidance were required to sort PGCs bilaterally. Repellent activity provided by wunen (wun) and wunen-2 (wun-2) expressed in the central nervous system, however, is essential in this migration process and controls PGC survival. Our results suggest that expression of wun/wun-2 repellents along the migratory paths provides faithful control over the sorting of PGCs into two gonads and eliminates PGCs left in the middle of the embryo.

Identification of tissues and patterning events required for distinct steps in early migration of zebrafish primordial germ cells

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5295-5307 ◽  
Author(s):  
G. Weidinger ◽  
U. Wolke ◽  
M. Koprunner ◽  
M. Klinger ◽  
E. Raz
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Paraxial Mesoderm ◽  
Molecular Characteristics ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Migration Process ◽  
Early Migration ◽  
Somatic Tissues

In many organisms, the primordial germ cells have to migrate from the position where they are specified towards the developing gonad where they generate gametes. Extensive studies of the migration of primordial germ cells in Drosophila, mouse, chick and Xenopus have identified somatic tissues important for this process and demonstrated a role for specific molecules in directing the cells towards their target. In zebrafish, a unique situation is found in that the primordial germ cells, as marked by expression of vasa mRNA, are specified in random positions relative to the future embryonic axis. Hence, the migrating cells have to navigate towards their destination from various starting positions that differ among individual embryos. Here, we present a detailed description of the migration of the primordial germ cells during the first 24 hours of wild-type zebrafish embryonic development. We define six distinct steps of migration bringing the primordial germ cells from their random positions before gastrulation to form two cell clusters on either side of the midline by the end of the first day of development. To obtain information on the origin of the positional cues provided to the germ cells by somatic tissues during their migration, we analyzed the migration pattern in mutants, including spadetail, swirl, chordino, floating head, cloche, knypek and no isthmus. In mutants with defects in axial structures, paraxial mesoderm or dorsoventral patterning, we find that certain steps of the migration process are specifically affected. We show that the paraxial mesoderm is important for providing proper anteroposterior information to the migrating primordial germ cells and that these cells can respond to changes in the global dorsoventral coordinates. In certain mutants, we observe accumulation of ectopic cells in different regions of the embryo. These ectopic cells can retain both morphological and molecular characteristics of primordial germ cells, suggesting that, in zebrafish at the early stages tested, the vasa-expressing cells are committed to the germ cell lineage.

scholarly journals The Bric-à-Brac transcription factors are necessary for formation of functional germline stem cell niches through control of dpp expression in the Drosophila melanogaster ovary

2019 ◽  
Author(s):  
Laurine Miscopein Saler ◽  
Mathieu Bartoletti ◽  
Virginie Hauser ◽  
Anne-Marie Pret ◽  
Laurent Theodore ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Stem Cell ◽  
Transcription Factors ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Somatic Cells ◽  
Bmp Signaling ◽  
Germline Stem Cell ◽  
Larval Stages ◽  
Functional Germline

AbstractMany studies have focused on the mechanisms of stem cell maintenance via their interaction with a particular niche or microenvironment in adult tissues, but how formation of a functional niche is initiated, including how stem cells within a niche are established, is less well understood. Adult Drosophila melanogaster ovary Germline Stem Cell (GSC) niches are comprised of somatic cells forming a stack called a Terminal Filament (TF) and underlying Cap Cells (CCs) and Escort Cells (ECs), which are in direct contact with GSCs. In the adult, the Engrailed (En) transcription factor is specifically expressed in niche cells where it directly controls expression of the decapentaplegic gene (dpp) encoding a member of the Bone Morphogenetic Protein (BMP) family of secreted signaling molecules, which are key factors for GSC maintenance. In late third instar larval ovaries, in response to BMP signaling from newly-formed niches, adjacent primordial germ cells become GSCs. The bric-à-brac paralogs (bab1 and bab2) encode BTB/POZ-domain containing transcription factors, that are also expressed in developing GSCs niches where they are required for TF formation. Here, we demonstrate that Bab1 and Bab2 display redundant cell autonomous function for TF morphogenesis and we identify a new function for these genes in GSC establishment. Moreover, we show that Bab proteins control dpp expression in otherwise correctly specified CCs, independently of En and its paralog Invected (Inv). In fact, our results also indicate that en/inv function in larval stages are neither essential for TF formation, nor GSC establishment. Finally, when bab2 was overexpressed in ovarian somatic cells outside of the niche, where en/inv were not expressed, ectopic BMP signaling activation was induced in adjacent germ cells of adult ovaries, which formed GSC-like tumors. Together, these results indicate that Bab transcription factors are positive regulators of BMP signaling for acquisition of GSC status.

Primordial Germ Cells of Drosophila melanogaster

2018 ◽  
pp. 145-151 ◽  
Author(s):  
Leif Benner ◽  
Girish Deshpande ◽  
Dorothy A. Lerit
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Cells ◽  
Primordial Germ Cells

Hexachlorobenzene toxicity in the rat ovary: II. Ultrastructure induced by medium (10 mg/kg) dose exposure

1992 ◽  
Vol 50 (1) ◽  
pp. 668-669
Author(s):  
Amreek Singh ◽  
Warren G. Foster ◽  
Anna Dykeman ◽  
David C. Villeneuve
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Surface Epithelium ◽  
Morphological Parameters ◽  
Comprehensive Investigation ◽  
Ovary Surface Epithelium ◽  
Rat Ovary ◽  
High Doses

Hexachlorobenzene (HCB) is a known toxicant that is found in the environment as a by-product during manufacture of certain pesticides. This chlorinated chemical has been isolated from many tissues including ovary. When administered in high doses, HCB causes degeneration of primordial germ cells and ovary surface epithelium in sub-human primates. A purpose of this experiment was to determine a no-effect dose of the chemical on the rat ovary. The study is part of a comprehensive investigation on the effects of the compound on the biochemical, hematological, and morphological parameters in the monkey and rat.

Transfusion of Chick Primordial Germ Cells into Quail Embryos and their Settlement in Gonads

1998 ◽  
Vol 69 (10) ◽  
pp. 911-915 ◽  
Author(s):  
Tamao ONO ◽  
Ryohei YOKOI ◽  
Seishi MAEDA ◽  
Takao NISHIDA ◽  
Hirohiko AOYAMA
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells
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