scholarly journals Transcription factor AP2 controls cnidarian germ cell induction

Science ◽  
2020 ◽  
Vol 367 (6479) ◽  
pp. 757-762 ◽  
Author(s):  
Timothy Q. DuBuc ◽  
Christine E. Schnitzler ◽  
Eleni Chrysostomou ◽  
Emma T. McMahon ◽  
Febrimarsa ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Adult Stem Cells ◽  
Germ Line ◽  
Cell Induction ◽  
Cell Commitment ◽  
I Cells

Clonal animals do not sequester a germ line during embryogenesis. Instead, they have adult stem cells that contribute to somatic tissues or gametes. How germ fate is induced in these animals, and whether this process is related to bilaterian embryonic germline induction, is unknown. We show that transcription factor AP2 (Tfap2), a regulator of mammalian germ lines, acts to commit adult stem cells, known as i-cells, to the germ cell fate in the clonal cnidarian Hydractinia symbiolongicarpus. Tfap2 mutants lacked germ cells and gonads. Transplanted wild-type cells rescued gonad development but not germ cell induction in Tfap2 mutants. Forced expression of Tfap2 in i-cells converted them to germ cells. Therefore, Tfap2 is a regulator of germ cell commitment across germ line–sequestering and germ line–nonsequestering animals.

The development of the testis of the Merino ram, with special reference to the orgin of the adult stem cells

1962 ◽  
Vol 13 (3) ◽  
pp. 487 ◽  
Author(s):  
CS Sapsford
Keyword(s):  
Stem Cells ◽  
Basement Membrane ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Adult Stem Cells ◽  
Germ Line ◽  
Primordial Germ Cells ◽  
Seminiferous Tubules ◽  
Stages Of Development ◽  
Striking Change

In the ram, as in other mammals, the sex cords are made up of two types of cell: indifferent cells (derivatives of the coelomic epithelium) and primordial germ cells. In the cords, each type pursues a separate and independent line of development to become respectively the Sertoli cells and the stem cells (type A spermatogonia) of the adult testis. The principal changes taking place in the primordial germ cells (gonocytes) are a reduction in the size and number of the Feulgen-positive particles in the nuclei, the appearance and subsequent fusion of the nucleoli, and, finally, an increase in the size of the nuclei. While these changes are taking place, the cytoplasm increases in volume and inclusions become more numerous. Cells which have undergone all these transformations have been called prospermatogonia. The cells of the germ line are at first more centrally placed in the sex cords than the indifferent cells. Just before spermatogenesis begins, they migrate to the basement membrane of the seminiferous tubules. All germ cells in tubules in which spermatogenesis has been initiated are seen as prospermatogonia. These cells become flattened against the basement membrane, and their nuclei become more oval in shape. They thus become identical with the stem cells of the adult. Little change is evident in the nuclei of the indifferent cells until puberty. Feulgen-positive material is found in the form of coarse granules at earlier stages of development. At puberty, these granules become dispersed to give a much more homogeneous nucleus. Concurrently, nuclei increase in size, and single or double true nucleoli can be identified. During development, increases in cytoplasmic volume take place. Although cell boundaries between indifferent cells cannot be seen in fixed material, phase contrast observations of fresh material have demonstrated that some forms exist as mononucleate units. It could not be determined whether the same was true in the case of Sertoli cells. No striking change in the relative numbers of glandular interstitial cells could be observed at different stages of development.

The fog-3 gene and regulation of cell fate in the germ line of Caenorhabditis elegans.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 561-577 ◽  
Author(s):  
R E Ellis ◽  
J Kimble
Keyword(s):  
Caenorhabditis Elegans ◽  
Germ Cell ◽  
Sexual Identity ◽  
Cell Fate ◽  
Germ Cells ◽  
Regulatory Network ◽  
Germ Line ◽  
The Other ◽  
Nematode Caenorhabditis Elegans ◽  
Inhibitory Interactions

Abstract In the nematode Caenorhabditis elegans, germ cells normally adopt one of three fates: mitosis, spermatogenesis or oogenesis. We have identified and characterized the gene fog-3, which is required for germ cells to differentiate as sperm rather than as oocytes. Analysis of double mutants suggests that fog-3 is absolutely required for spermatogenesis and acts at the end of the regulatory hierarchy controlling sex determination for the germ line. By contrast, mutations in fog-3 do not alter the sexual identity of other tissues. We also have characterized the null phenotype of fog-1, another gene required for spermatogenesis; we demonstrate that it too controls the sexual identity of germ cells but not of other tissues. Finally, we have studied the interaction of these two fog genes with gld-1, a gene required for germ cells to undergo oogenesis rather than mitosis. On the basis of these results, we propose that germ-cell fate might be controlled by a set of inhibitory interactions among genes that specify one of three fates: mitosis, spermatogenesis or oogenesis. Such a regulatory network would link the adoption of one germ-cell fate to the suppression of the other two.

002. REGULATION OF PLURIPOTENCY AND CELL CYCLE IN FETAL GERM CELLS

2009 ◽  
Vol 21 (9) ◽  
pp. 2
Author(s):  
P. Western ◽  
J. Van Den Bergen ◽  
D. Miles ◽  
R. Ralli ◽  
A. Sinclair
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Transcriptional Regulation ◽  
Germ Cell ◽  
Germ Cells ◽  
Germ Line ◽  
Cell Lineage ◽  
Mitotic Arrest ◽  
Male Germ Cells ◽  
Developmental Potential

The germ cell lineage is unique in that it must ensure that the genome retains the complete developmental potential (totipotency) that supports development in the following generation. This is achieved through a number of mechanisms that prevent the early germ cell lineage from somatic differentiation and promote the capactity for functional totipotency. Part of this process involves the retained germ line expression of key genes that regulate pluripotency in embryonic stem cells, embryonic germ cells and some embryonal carcinoma cells, the stem cells of testicular tumours. Despite this, germ cells are not intrinsically pluripotent and must differentiate along the male or female pathways, a process which requires commitment of the bi-potential primordial germ cells to the spermatogenic (male) pathway and their entry into mitotic arrest, or to the oogenic pathway (females) and entry into meiosis. This involves robust regulation of regulatory networks controlling pluripotency, cell cycle and sex specific differentiation. Our work aims to further understand the mechanisms controlling differentiation, pluripotency and cell cycle in early male and female germ cells. Our data shows that mitotic arrest of male germ cells involves strict regulation of the G1-S phase check-point through the retinoblastoma protein. In addition, suppression of pluripotency in differentiating male germ cells involves post-transcriptional regulation of OCT4, transcriptional regulation of Sox2 and Nanog and methylation of the Sox2 and Nanog promoters. Further understanding of these processes promises to lead to a greater understanding of the molecular mechanisms underlying control of pluripotency, cell cycle and differentiation in the germ line and the initiation of germ cell derived testis tumours.

The germ line regulates somatic cyst cell proliferation and fate during Drosophila spermatogenesis

Development ◽  
1996 ◽  
Vol 122 (8) ◽  
pp. 2437-2447 ◽  
Author(s):  
P. Gonczy ◽  
S. DiNardo
Keyword(s):  
Stem Cells ◽  
Cell Proliferation ◽  
Cell Fate ◽  
Germ Cells ◽  
Germ Line ◽  
Lineage Tracing ◽  
Somatic Stem Cells ◽  
Daughter Cyst ◽  
Cyst Cell ◽  
Cyst Cells

Spermatogenesis relies on the function of germ-line stem cells, as a continuous supply of differentiated spermatids is produced throughout life. In Drosophila, there must also be somatic stem cells that produce the cyst cells that accompany germ cells throughout spermatogenesis. By lineage tracing, we demonstrate the existence of such somatic stem cells and confirm that of germ-line stem cells. The somatic stem cells likely correspond to the ultrastructurally described cyst progenitor cells. The stem cells for both the germ-line and cyst lineage are anchored around the hub of non-dividing somatic cells located at the testis tip. We then address whether germ cells regulate the behavior of somatic hub cells, cyst progenitors and their daughter cyst cells by analyzing cell proliferation and fate in testes in which the germ line has been genetically ablated. Daughter cyst cells, which normally withdraw from the cell cycle, continue to proliferate in the absence of germ cells. In addition, cells from the cyst lineage switch to the hub cell fate. Male-sterile alleles of chickadee and diaphanous, which are deficient in germ cells, exhibit similar cyst cell phenotypes. We conclude that signaling from germ cells regulates the proliferation and fate of cells in the somatic cyst lineage.

Germ cells of the mammalian female: A limited or renewable resource?

2021 ◽  
Author(s):  
Mathilde Hainaut ◽  
Hugh J Clarke
Keyword(s):  
Stem Cells ◽  
Cell Fate ◽  
Germ Cells ◽  
Germ Line ◽  
Marker Gene ◽  
Somatic Cells ◽  
Renewable Resource ◽  
Weight Of Evidence ◽  
Fetal Life

Abstract In many non-mammalian organisms, a population of germ-line stem cells supports continuing production of gametes during most or all the life of the individual, and germ-line stem cells are also present and functional in male mammals. Traditionally, however, they have been thought not to exist in female mammals, who instead generate all their germ cells during fetal life. Over the last several years, this dogma has been challenged by several reports, while supported by others. We describe and compare these conflicting studies with the aim of understanding how they came to opposing conclusions. We first consider studies that, by examining marker-gene expression, the fate of genetically marked cells, and consequences of depleting the oocyte population, addressed whether ovaries of post-natal females contain oogonial stem cells (OSC) that give rise to new oocytes. We next discuss whether ovaries contain cells that, even if inactive under physiological conditions, nonetheless possess OSC properties that can be revealed through cell-culture. We then examine studies of whether cells harvested after long-term culture of cells obtained from ovaries can, following transplantation into ovaries of recipient females, give rise to oocytes and offspring. Finally, we note studies where somatic cells have been re-programmed to acquire a female germ-cell fate. We conclude that the weight of evidence strongly supports the traditional interpretation that germ-line stem cells do not exist post-natally in female mammals. However, the ability to generate germ cells from somatic cells in vitro establishes a method to generate new gametes from cells of post-natal mammalian females.

scholarly journals Characterization of Alternative Splicing (AS) Events during Chicken (Gallus gallus) Male Germ-Line Stem Cell Differentiation with Single-Cell RNA-seq

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1469
Author(s):  
Changhua Sun ◽  
Kai Jin ◽  
Qisheng Zuo ◽  
Hongyan Sun ◽  
Jiuzhou Song ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Alternative Splicing ◽  
Cell Differentiation ◽  
Germ Cell ◽  
Germ Cells ◽  
Germ Line ◽  
Rna Seq ◽  
Germ Cell Differentiation ◽  
Genome Wide

Alternative splicing (AS) is a ubiquitous, co-transcriptional, and post-transcriptional regulation mechanism during certain developmental processes, such as germ cell differentiation. A thorough understanding of germ cell differentiation will help us to open new avenues for avian reproduction, stem cell biology, and advances in medicines for human consumption. Here, based on single-cell RNA-seq, we characterized genome-wide AS events in manifold chicken male germ cells: embryonic stem cells (ESCs), gonad primordial germ cells (gPGCs), and spermatogonia stem cells (SSCs). A total of 38,494 AS events from 15,338 genes were detected in ESCs, with a total of 48,955 events from 14,783 genes and 49,900 events from 15,089 genes observed in gPGCs and SSCs, respectively. Moreover, this distribution of AS events suggests the diverse splicing feature of ESCs, gPGCs, and SSCs. Finally, several crucial stage-specific genes, such as NANOG, POU5F3, LIN28B, BMP4, STRA8, and LHX9, were identified in AS events that were transmitted in ESCs, gPGCs, and SSCs. The gene expression results of the RNA-seq data were validated by qRT-PCR. In summary, we provided a comprehensive atlas of the genome-wide scale of the AS event landscape in male chicken germ-line cells and presented its distribution for the first time. This research may someday improve treatment options for men suffering from male infertility.

scholarly journals Conversion of Germ Cells to Somatic Cell Types in C. elegans

2020 ◽  
Vol 8 (4) ◽  
pp. 24 ◽  
Author(s):  
Nida ul Fatima ◽  
Baris Tursun
Keyword(s):  
Transcription Factor ◽  
Germ Cell ◽  
Somatic Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Molecular Mechanisms ◽  
Essential Property ◽  
C Elegans ◽  
Differentiated Cells ◽  
A Cell

The potential of a cell to produce all types of differentiated cells in an organism is termed totipotency. Totipotency is an essential property of germ cells, which constitute the germline and pass on the parental genetic material to the progeny. The potential of germ cells to give rise to a whole organism has been the subject of intense research for decades and remains important in order to better understand the molecular mechanisms underlying totipotency. A better understanding of the principles of totipotency in germ cells could also help to generate this potential in somatic cell lineages. Strategies such as transcription factor-mediated reprogramming of differentiated cells to stem cell-like states could benefit from this knowledge. Ensuring pluripotency or even totipotency of reprogrammed stem cells are critical improvements for future regenerative medicine applications. The C. elegans germline provides a unique possibility to study molecular mechanisms that maintain totipotency and the germ cell fate with its unique property of giving rise to meiotic cells Studies that focused on these aspects led to the identification of prominent chromatin-repressing factors such as the C. elegans members of the Polycomb Repressive Complex 2 (PRC2). In this review, we summarize different factors that were recently identified, which use molecular mechanisms such as control of protein translation or chromatin repression to ensure maintenance of totipotency and the germline fate. Additionally, we focus on recently identified factors involved in preventing transcription-factor-mediated conversion of germ cells to somatic lineages. These so-called reprogramming barriers have been shown in some instances to be conserved with regard to their function as a cell fate safeguarding factor in mammals. Overall, continued studies assessing the different aspects of molecular pathways involved in maintaining the germ cell fate in C. elegans may provide more insight into cell fate safeguarding mechanisms also in other species.

111 CLONING AND CHARACTERIZATION OF PIG VASA HOMOLOG GENE AND ITS SPECIFIC EXPRESSION IN GERM CELL LINEAGE

2005 ◽  
Vol 17 (2) ◽  
pp. 206
Author(s):  
G.S. Lee ◽  
S.H. Lee ◽  
H.S. Kim ◽  
E.B. Jeung ◽  
S.K. Kang ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Germ Line ◽  
Pcr Amplification ◽  
Molecular Probes ◽  
Cloning And Expression ◽  
Soil Nematode ◽  
Rt Pcr ◽  
Specific Expression ◽  
Cell Commitment

All of the vasa homologue genes in C. elegans (Caenorhabditis elegens, a free-living soil nematode), xenopus, zebrafish, mouse, human, chicken, trout, and rat exhibited a germ line-specific expression and are used as specific molecular probes to distinguish the developmental profile of germ cells. In order to determine a useful marker for the research of germ cell commitment and development in pigs, we investigated the cloning and expression profile of porcine vasa homolog gene (Pvh). A Pvh cDNA gene of size 2172 bps (submitted to NCBI gene Bank No. AY626785) was cloned from pig ovary by reverse transcription-polymerase chain reaction (RT-PCR) amplification. The amplification was repeated three times and each RT-PCR product was sequenced. The isolated cDNA had 724 deduced amino acids with significant homology to mouse (85%) or human (91%) vasa. The Pvh sequence presents five copies of the RGG motifs and the DEAD box. By RT-PCR amplification, the expression of Pvh mRNA was restricted to the ovary and testis and was undetectable in somatic tissues including brain, whole blood, heart, lung, kidney, spleen, intestine, and liver. When analyzed by RT-PCR amplification, during pre-implantation embryo development, Pvh was transcribed in oocytes and fertilized 2-cell embryos (no difference in the expression levels between oocytes and fertilized 2-cell embryos), but not in 4-cell, 8-cell, morula and blastocyst stages. Using mouse vasa antibody (kindly donated from Dr. Noce, Japan; tested in porcine cells with porcine oocytes and mouse oocytes as positive control and with porcine brain cells as negative control), immunohistochemical analysis of fetal (Day 100) and adult gonad sections revealed that Pvh protein was specifically expressed in proliferating primordial germ cells (PGC), oocytes and spermatocytes. Interestingly, Pvh protein was not expressed in embryonic germ cells, but it was strongly expressed in freshly isolated PGC. Our results indicate that Pvh gene is specifically transcribed in pig germ cells. This study was supported by grants from the Korean Ministry of Science and Technology (Biodiscovery) and the Biogreen 21-1000520030100000.

scholarly journals In vitro germ cell differentiation from embryonic stem cells of mice: induction control by BMP4 signalling

2016 ◽  
Vol 36 (6) ◽  
Author(s):  
Zohreh Makoolati ◽  
Mansoureh Movahedin ◽  
Mehdi Forouzandeh-Moghadam
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Germ Cell ◽  
Germ Line ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Culture Systems ◽  
Germ Cell Differentiation ◽  
Cell Commitment

The present study aims to confirm and analyse germ cell-related patterns and specific gene expressions at a very early stage of cell commitment. Following the XY cytogenetic confirmation of the CCE mouse embryonic stem cells (mESCs) line, cells were cultured to form embryoid bodies (EBs). Expression pattern assessment of the mouse vasa homologue (Mvh), Stra8, α6 and β1 integrin genes in ESC and 1–3-day-old EB showed that all genes except α6 integrin were expressed in the ESC. The mean calibration of Mvh, Stra8 and α6 integrin expression significantly increased upon EB formation compared with the ESCs. During mouse embryogenesis, the signalling of bone morphogenetic protein (BMP) is essential for germ-line formation. To investigate its role in germ-line induction in vitro, mESCs were cultured as 1-day-old EB aggregates with BMP4 for 4 days in STO co-culture systems, in the presence and absence of 5 ng/ml BMP4. At the end of the culture period, colony assay (number and diameter) was performed and the viability percentage and proliferation rate was determined. There were no significant statistical differences in the abovementioned criteria between these two groups. Moreover, the expression of Mvh, α6 and β1 integrins, Stra8 and Piwil2 genes was evaluated in co-culture groups. The molecular results of co-culture groups showed higher–but insignificant–Piwil2 and significant α6 integrin expressions in BMP4 treated co-culture systems. These results confirmed that the EB system and the presence of BMP4 in a STO co-culture system improve the differentiation of ESCs to germ cell.

Ectopic expression of the Drosophila Bam protein eliminates oogenic germline stem cells

Development ◽  
1997 ◽  
Vol 124 (18) ◽  
pp. 3651-3662 ◽  
Author(s):  
B. Ohlstein ◽  
D. McKearin
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Ectopic Expression ◽  
Cell Lineage ◽  
Limiting Factor ◽  
Germline Stem Cells ◽  
Stem Cell Divisions

The Drosophila germ-cell lineage has emerged as a remarkable system for identifying genes required for changes in cell fate from stem cells into more specialized cells. Previous work indicates that bam expression is necessary for cystoblast differentiation; bam mutant germ cells fail to differentiate, but instead proliferate like stem cells. This paper reports that ectopic expression of bam is sufficient to extinguish stem cell divisions. Heat-induced bam+ expression specifically eliminated oogenic stem cells while somatic stem cell populations were not affected. Together with previous studies of the timing of bam mRNA and protein expression and the state of arrest in bam mutant cells, these data implicate Bam as a direct regulator of the switch from stem cell to cystoblast. Surprisingly, ectopic bam+ had no deleterious consequences for male germline cells suggesting that Bam may regulate somewhat different steps of germ-cell development in oogenesis and spermatogenesis. We discuss a model for how bam+ could direct differentiation based on our data (McKearin and Ohlstein, 1995) that Bam protein is essential to assemble part of the germ-cell-specific organelle, the fusome. We propose that fusome biogenesis is an obligate step for cystoblast cell fate and that Bam is the limiting factor for fusome maturation in female germ cells.

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