scholarly journals Analysis of the multiple roles of gld-1 in germline development: interactions with the sex determination cascade and the glp-1 signaling pathway.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 607-630 ◽  
Author(s):  
R Francis ◽  
E Maine ◽  
T Schedl
Keyword(s):  
Sex Determination ◽  
Germ Cell ◽  
Signaling Pathway ◽  
Germ Cells ◽  
Meiotic Prophase ◽  
Tumor Formation ◽  
Germline Development ◽  
Epistasis Analysis ◽  
Cell Ablation ◽  
Genetic Epistasis

Abstract The Caenorhabditis elegans gene gld-1 is essential for oocyte development; in gld-1 (null) hermaphrodites, a tumor forms where oogenesis would normally occur. We use genetic epistasis analysis to demonstrate that tumor formation is dependent on the sexual fate of the germline. When the germline sex determination pathway is set in the female mode (terminal fem/fog genes inactive), gld-1 (null) germ cells exit meiotic prophase and proliferate to form a tumor, but when the pathway is set in the male mode, they develop into sperm. We conclude that the gld-1 (null) phenotype is cell-type specific and that gld-1(+) acts at the end of the cascade to direct oogenesis. We also use cell ablation and epistasis analysis to examine the dependence of tumor formation on the glp-1 signaling pathway. Although glp-1 activity promotes tumor growth, it is not essential for tumor formation by gld-1 (null) germ cells. These data also reveal that gld-1(+) plays a nonessential (and sex nonspecific) role in regulating germ cell proliferation before their entry into meiosis. Thus gld-1(+) may negatively regulate proliferation at two distinct points in germ cell development: before entry into meiotic prophase in both sexes (nonessential premeiotic gld-1 function) and during meiotic prophase when the sex determination pathway is set in the female mode (essential meiotic gld-1 function).

The fusome organizes the microtubule network during oocyte differentiation in Drosophila

Development ◽  
2000 ◽  
Vol 127 (19) ◽  
pp. 4253-4264 ◽  
Author(s):  
N.C. Grieder ◽  
M. de Cuevas ◽  
A.C. Spradling
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Meiotic Prophase ◽  
Crucial Role ◽  
Skeletal Structure ◽  
Network Organization ◽  
Microtubule Network ◽  
Complex Process ◽  
Gamma Tubulin ◽  
Oocyte Differentiation

Differentiation of the Drosophila oocyte takes place in a cyst of 16 interconnected germ cells and is dependent on a network of microtubules that becomes polarized as differentiation progresses (polarization). We have investigated how the microtubule network polarizes using a GFP-tubulin construct that allows germ-cell microtubules to be visualized with greater sensitivity than in previous studies. Unexpectedly, microtubules are seen to associate with the fusome, an asymmetric germline-specific organelle, which elaborates as cysts form and undergoes complex changes during cyst polarization. This fusome-microtubule association occurs periodically during late interphases of cyst divisions and then continuously in 16-cell cysts that have entered meiotic prophase. As meiotic cysts move through the germarium, microtubule minus ends progressively focus towards the center of the fusome, as visualized using a NOD-lacZ marker. During this same period, discrete foci rich in gamma tubulin that very probably correspond to migrating cystocyte centrosomes also associate with the fusome, first on the fusome arms and then in its center, subsequently moving into the differentiating oocyte. The fusome is required for this complex process, because microtubule network organization and polarization are disrupted in hts(1) mutant cysts, which lack fusomes. Our results suggest that the fusome, a specialized membrane-skeletal structure, which arises in early germ cells, plays a crucial role in polarizing 16-cell cysts, at least in part by interacting with microtubules and centrosomes.

scholarly journals A long noncoding RNA binding to QKI-5 regulates germ cell apoptosis via p38 MAPK signaling pathway

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Kai Li ◽  
Shunshun Zhong ◽  
Yanyun Luo ◽  
Dingfeng Zou ◽  
Mengzhen Li ◽  
...  
Keyword(s):  
Germ Cell ◽  
Signaling Pathway ◽  
P38 Mapk ◽  
Cell Apoptosis ◽  
Rna Binding ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Germline Development ◽  
Germ Cell Apoptosis ◽  
Male Germline

Abstract Spermatogenesis is the complex process of male germline development and requires coordinated interactions by multiple gene products that undergo strict developmental regulations. Increasing evidence has suggested that a number of long noncoding RNAs (lncRNAs) may function as important regulatory molecules in various physiological and pathological processes by binding to specific proteins. Here, we identified a subset of QKI-5-binding lncRNAs in the mouse testis through the integrated analyses of RNA immunoprecipitation (RIP)-microarray and biological verification. Among the lncRNAs, we revealed that NONMMUT074098.2 (Lnc10), which was highly expressed in the spermatogonia and spermatocytes of the testis, interacted with QKI-5. Furthermore, Lnc10 depletion promoted germ cell apoptosis via the activation of p38 MAPK, whereas the simultaneous knockdown of QKI-5 could rescue the apoptotic phenotype and the activation of p38 MAPK, which were induced by the loss of Lnc10. These data indicated that the Lnc10-QKI-5 interaction was associated with the regulatory roles of QKI-5 and that the Lnc10-QKI-5 interaction inhibited the regulation of QKI-5 on the downstream p38 MAPK signaling pathway. Additionally, we functionally characterized the biological roles of Lnc10 and found that the knockdown of Lnc10 promoted the apoptosis of spermatogenic cells in vivo; this suggested that Lnc10 had an important biological role in mouse spermatogenesis. Thus, our study provides a potential strategy to investigate the biological significance of lncRNA-RBP interactions during male germline development.

scholarly journals Absence of mDazl produces a final block on germ cell development at meiosis

Reproduction ◽  
2003 ◽  
pp. 589-597 ◽  
Author(s):  
PT Saunders ◽  
JM Turner ◽  
M Ruggiu ◽  
M Taggart ◽  
PS Burgoyne ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Meiotic Prophase ◽  
Rna Binding ◽  
Developmental Stages ◽  
Cell Loss ◽  
Functional Differentiation ◽  
Autosomal Gene ◽  
Fetal Life ◽  
Male And Female

The autosomal gene DAZL is a member of a family of genes (DAZL, DAZ, BOULE), all of which contain a consensus RNA binding domain and are expressed in germ cells. Adult male and female mice null for Dazl lack gametes. In order to define more precisely the developmental stages in germ cells that require Dazl expression, the patterns of germ cell loss in immature male and female wild-type (+/+, WT) and Dazl -/- (DazlKO) mice were analysed. In females, loss of germ cells occurred during fetal life and was coincident with progression of cells through meiotic prophase. In males, testes were recovered from WT and DazlKO males obtained before and during the first wave of spermatogenesis (days 2-19). Mitotically active germ cells were present up to and including day 19. Functional differentiation of spermatogonia associated with detection of c-kit positive cells did not depend upon expression of Dazl. RBMY-positive cells (A, intermediate, B spermatogonia, zygotene and preleptotene spermatocytes) were reduced in DazlKO compared with WT testes. Staining of cell squashes from day 19 testes with anti-gamma-H2AX and anti-SCP3 antibodies showed that germ cells from DazlKO males were unable to progress beyond the leptotene stage of meiotic prophase I. It was concluded that in the absence of Dazl, germ cells can complete mitosis, and embark on functional differentiation but that, in both sexes, progression through meiotic prophase requires this RNA binding protein.

scholarly journals OBSERVATIONS ON EARLY GERM CELL DEVELOPMENT AND PREMEIOTIC RIBOSOMAL DNA AMPLIFICATION IN XENOPUS LAEVIS

1974 ◽  
Vol 62 (2) ◽  
pp. 460-472 ◽  
Author(s):  
Marvin R. Kalt ◽  
Joseph G. Gall
Keyword(s):  
Xenopus Laevis ◽  
Germ Cell ◽  
Ribosomal Dna ◽  
Germ Cells ◽  
Dna Hybridization ◽  
Meiotic Prophase ◽  
Germ Line ◽  
Tritiated Thymidine ◽  
Gradient Centrifugation ◽  
Dna Amplification

The origin of premeiotic ribosomal DNA (rDNA) amplification in germ-line cells of Xenopus laevis has been examined using in situ RNA-DNA hybridization on cytological preparations, tritiated thymidine autoradiography, and isopycnic density gradient centrifugation. Primordial germ cells (PGC), from the time they first become localized in the genital ridge at day no. 4 of development, until approximately day no. 22, remain in an extended interphase condition. During this time PGC do not incorporate tritiated thymidine, have near diploid levels of rDNA as demonstrated by cytological RNA-DNA hybridization, and possess only one or two nucleoli. Starting on day no. 22–24, mitosis, sexual differentiation, and rDNA gene amplification all begin in the germ cells. Multiple nucleoli also make their appearance at this stage. Ribosomal DNA amplification continues in gonial cells as long as they remain mitotically active. Amplified copies of rDNA are lost from germ cells at the onset of meiotic prophase. This loss is probably permanent in the male germ line, but variable and temporary in the female germ line. Early gonial cells in the ovary have been deduced to have an average cycle time for each mitotic division of between 3.8 and 4.3 days at a temperature of 21°C. Some oogonia appear to divide only four times before entering meiotic prophase, while the average during the initial wave of germ cell division is nine. Finally, a satellite DNA has been isolated from adult testes which has a density in neutral cesium chloride corresponding to the density of amplified oocyte rDNA. This satellite is not present in DNA isolated from somatic tissues of Xenopus.

scholarly journals Germ Cell Biology Sex determination in mammalian germ cells

2015 ◽  
Vol 0 (0) ◽  
pp. 0 ◽  
Author(s):  
Josephine Bowles ◽  
CassyM Spiller
Keyword(s):  
Sex Determination ◽  
Germ Cell ◽  
Germ Cells ◽  
Cell Biology

scholarly journals Spermatogenesis in testes of Dazl null mice after transplantation of wild-type germ cells

Reproduction ◽  
2003 ◽  
pp. 599-604 ◽  
Author(s):  
R R ◽  
R Speed ◽  
M Taggart ◽  
HJ Cooke
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Germ Cells ◽  
Meiotic Prophase ◽  
Spermatogonial Stem Cells ◽  
Cell Suspensions ◽  
Male Mice ◽  
Wild Type

Dazl knockout male mice are infertile because their germ cells are unable to complete the first meiotic prophase in the first wave of spermatogenesis and thereafter decrease in number due to a block at the A-aligned to A1 transition. The ability of the surviving somatic components of the testes to retain their function in the absence of mature germ cells was tested by injecting marked wild-type germ cell suspensions containing spermatogonial stem cells. Comparison of the frequency and extent of colonization of Dazl knockout testes with that of testes chemically depleted of germ cells showed little if any difference. It was concluded that Dazlko testes seem unimpaired in their ability to support spermatogenesis. Therefore, Dazlko testes provide a useful and reliable recipient in which to evaluate spermatogonial stem cells. The results furthermore demonstrate that the somatic compartment of the testis of these animals retains functionality.

scholarly journals Sex Determination in the Drosophila Germline Is Dictated by the Sexual Identity of the Surrounding Soma

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1741-1756 ◽  
Author(s):  
J A Waterbury ◽  
J I Horabin ◽  
D Bopp ◽  
P Schedl
Keyword(s):  
Sex Determination ◽  
Sexual Identity ◽  
Signaling Pathway ◽  
X Chromosome ◽  
Germ Cells ◽  
Chromosome Counting ◽  
Counting System ◽  
Germline Expression ◽  
Female Specific ◽  
Male Specific

Abstract It has been suggested that sexual identity in the germline depends upon the combination of a nonautonomous somatic signaling pathway and an autonomous X chromosome counting system. In the studies reported here, we have examined the role of the sexual differentiation genes transformer (tra) and doublesex (dsx) in regulating the activity of the somatic signaling pathway. We asked whether ectopic somatic expression of the female products of the tra and dsx genes could feminize the germline of XY animals. We find that TraF is sufficient to feminize XY germ cells, shutting off the expression of male-specific markers and activating the expression of female-specific markers. Feminization of the germline depends upon the constitutively expressed transformer-2 (tra-2) gene, but does not seem to require a functional dsx gene. However, feminization of XY germ cells by TraF can be blocked by the male form of the Dsx protein (DsxM). Expression of the female form of dsx, DsxF, in XY animals also induced germline expression of female markers. Taken together with a previous analysis of the effects of mutations in tra, tra-2, and dsx on the feminization of XX germ cells in XX animals, our findings indicate that the somatic signaling pathway is redundant at the level tra and dsx. Finally, our studies call into question the idea that a cell-autonomous X chromosome counting system plays a central role in germline sex determination.

scholarly journals Male germline stem cells in non-human primates

2017 ◽  
Vol 4 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Swati Sharma ◽  
Joana M. D. Portela ◽  
Daniel Langenstroth-Röwer ◽  
Joachim Wistuba ◽  
Nina Neuhaus ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Germ Cells ◽  
Developmental Stages ◽  
Expression Patterns ◽  
Regulatory Mechanisms ◽  
Primate Species ◽  
Germline Stem Cells ◽  
Germline Development ◽  
Human Primate

Abstract. Over the past few decades, several studies have attempted to decipher the biology of mammalian germline stem cells (GSCs). These studies provide evidence that regulatory mechanisms for germ cell specification and migration are evolutionarily conserved across species. The characteristics and functions of primate GSCs are highly distinct from rodent species; therefore the findings from rodent models cannot be extrapolated to primates. Due to limited availability of human embryonic and testicular samples for research purposes, two non-human primate models (marmoset and macaque monkeys) are extensively employed to understand human germline development and differentiation. This review provides a broader introduction to the in vivo and in vitro germline stem cell terminology from primordial to differentiating germ cells. Primordial germ cells (PGCs) are the most immature germ cells colonizing the gonad prior to sex differentiation into testes or ovaries. PGC specification and migratory patterns among different primate species are compared in the review. It also reports the distinctions and similarities in expression patterns of pluripotency markers (OCT4A, NANOG, SALL4 and LIN28) during embryonic developmental stages, among marmosets, macaques and humans. This review presents a comparative summary with immunohistochemical and molecular evidence of germ cell marker expression patterns during postnatal developmental stages, among humans and non-human primates. Furthermore, it reports findings from the recent literature investigating the plasticity behavior of germ cells and stem cells in other organs of humans and monkeys. The use of non-human primate models would enable bridging the knowledge gap in primate GSC research and understanding the mechanisms involved in germline development. Reported similarities in regulatory mechanisms and germ cell expression profile in primates demonstrate the preclinical significance of monkey models for development of human fertility preservation strategies.

scholarly journals The sex determination master switch, Sex-lethal, responds to Hedgehog signaling in theDrosophilagermline

Development ◽  
2001 ◽  
Vol 128 (14) ◽  
pp. 2649-2660 ◽  
Author(s):  
Cynthia Vied ◽  
Jamila I. Horabin
Keyword(s):  
Sex Determination ◽  
Signaling Pathway ◽  
Germ Cells ◽  
Meiotic Recombination ◽  
Hedgehog Signaling ◽  
Nuclear Translocation ◽  
Hedgehog Signaling Pathway ◽  
Cubitus Interruptus ◽  
Protein Levels ◽  
Sex Lethal

Sex-lethal is the Drosophila melanogaster sex determination master switch. It is also required in female germ cells to control mitosis and meiotic recombination. As early germ cells mature, distinct changes in both Sex-lethal protein levels and localization occur. By manipulating the levels of Hedgehog and making germline clones of components in the hedgehog signaling pathway, we demonstrate that Hedgehog affects the nuclear translocation of Sex-lethal and the levels of the protein in early germ cells. This effect is mediated primarily through degradation. Consistent with the Hedgehog pathway regulating Sex-lethal, we find Sex-lethal in a complex with Fused and Costal-2, both downstream components of the pathway. This is the first demonstration that downstream components of the Hedgehog signaling pathway regulate a target other than Cubitus interruptus.

scholarly journals Crosstalk Between Retinoic Acid and Sex-Related Genes Controls Germ Cell Fate and Gametogenesis in Medaka

2021 ◽  
Vol 8 ◽  
Author(s):  
Mateus C. Adolfi ◽  
Amaury Herpin ◽  
Anabel Martinez-Bengochea ◽  
Susanne Kneitz ◽  
Martina Regensburger ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Differentiation ◽  
Sex Determination ◽  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Sex Differentiation ◽  
Model Species ◽  
Fish Model ◽  
Germ Cell Differentiation

Sex determination (SD) is a highly diverse and complex mechanism. In vertebrates, one of the first morphological differences between the sexes is the timing of initiation of the first meiosis, where its initiation occurs first in female and later in male. Thus, SD is intimately related to the responsiveness of the germ cells to undergo meiosis in a sex-specific manner. In some vertebrates, it has been reported that the timing for meiosis entry would be under control of retinoic acid (RA), through activation of Stra8. In this study, we used a fish model species for sex determination and lacking the stra8 gene, the Japanese medaka (Oryzias latipes), to investigate the connection between RA and the sex determination pathway. Exogenous RA treatments act as a stress factor inhibiting germ cell differentiation probably by activation of dmrt1a and amh. Disruption of the RA degrading enzyme gene cyp26a1 induced precocious meiosis and oogenesis in embryos/hatchlings of female and even some males. Transcriptome analyzes of cyp26a1–/–adult gonads revealed upregulation of genes related to germ cell differentiation and meiosis, in both ovaries and testes. Our findings show that germ cells respond to RA in a stra8 independent model species. The responsiveness to RA is conferred by sex-related genes, restricting its action to the sex differentiation period in both sexes.

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