A conserved requirement forFbxo7during male germ cell cytoplasmic remodelling

Summary statementFbxo7 is the substrate-recognition subunit of an SCF-type ubiquitin E3 ligase complex. It has physiologically important functions in regulating mitophagy, proteasome activity and the cell cycle in multiple cell types, like neurons, lymphocytes and erythrocytes. Here we show that in addition to the previously-known Parkinsonian and haematopoietic phenotypes, Fbxo7-deficient male mice are completely sterile. In these males, despite successful meiosis, nuclear elongation and eviction of histones from chromatin, the developing spermatids are phagocytosed by Sertoli cells during late spermiogenesis, as the cells undergo cytoplasmic remodelling. Surprisingly, despite the loss of all germ cells, there was no evidence of the symplast formation and cell sloughing that is typically associated with spermatid death in other mouse sterility models, suggesting that novel cell death and/or cell disposal mechanisms may be engaged in Fbxo7-deficient males. Mutation of theDrosophilaFbxo7 orthologue,nutcracker(ntc) was previously shown to cause sterility at a similar stage of germ cell development, indicating that the requirement for Fbxo7 is conserved. Thentcphenotype was attributed to proteasome mis-regulation via an interaction with the proteasome regulator, DmPI31. Our data suggest rather that in mice, the requirement for Fbxo7 is either independent of its interaction with PI31, or relates specifically to cytoplasmic proteasome activity during spermiogenesis.

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50 years of spermatogenesis: Sertoli cells and their interactions with germ cells

Biology of Reproduction ◽

10.1093/biolre/ioy027 ◽

2018 ◽

Vol 99 (1) ◽

pp. 87-100 ◽

Cited By ~ 27

Author(s):

Michael D Griswold

Keyword(s):

Germ Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Cultured Cells ◽

Cell Types ◽

Cell Development ◽

Specific Cell ◽

Germ Cell Development ◽

Cell Niche ◽

Transgenic Technologies

Abstract The complex morphology of the Sertoli cells and their interactions with germ cells has been a focus of investigators since they were first described by Enrico Sertoli. In the past 50 years, information on Sertoli cells has transcended morphology alone to become increasingly more focused on molecular questions. The goal of investigators has been to understand the role of the Sertoli cells in spermatogenesis and to apply that information to problems relating to male fertility. Sertoli cells are unique in that they are a nondividing cell population that is active for the reproductive lifetime of the animal and cyclically change morphology and gene expression. The numerous and distinctive junctional complexes and membrane specializations made by Sertoli cells provide a scaffold and environment for germ cell development. The increased focus of investigators on the molecular components and putative functions of testicular cells has resulted primarily from procedures that isolate specific cell types from the testicular milieu. Products of Sertoli cells that influence germ cell development and vice versa have been characterized from cultured cells and from the application of transgenic technologies. Germ cell transplantation has shown that the Sertoli cells respond to cues from germ cells with regard to developmental timing and has furthered a focus on spermatogenic stem cells and the stem cell niche. Very basic and universal features of spermatogenesis such as the cycle of the seminiferous epithelium and the spermatogenic wave are initiated by Sertoli cells and maintained by Sertoli-germ cell cooperation.

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Hmgcr promotes a long-range signal to attract germ cells which is aided by Wunens but independent of hh

10.1101/333575 ◽

2018 ◽

Author(s):

Kim Kenwrick ◽

Amrita Mukherjee ◽

Andrew Renault

Keyword(s):

Germ Cell ◽

Long Range ◽

Germ Cells ◽

Cell Types ◽

Final Position ◽

Expression Of Genes ◽

Germ Cell Migration ◽

Summary Statement ◽

Genetic Techniques ◽

Native Context

Summary StatementMigrating Drosophila germ cells are attracted by a long range Hmgcr mediated signal which is aided and acts simultaneously with Wunens suggesting that these pathways converge on a single chemoattractant.AbstractIn a developing embryo, many cell types migrate from their point of specification to their final position. This usually involves highly stereotyped routes which are determined through deployment of cell surface or secreted guidance molecules. Whilst genetic techniques have been successful in identifying these molecules, the distances over which such signals operate in their native context can be difficult to determine. Here we have quantified the range of an attractive signal for the migration of Drosophila germ cells. Their migration is guided by an attractive signal generated by the expression of genes in the 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (Hmgcr) pathway, and by a repulsive signal generated by the expression of Wunens. We demonstrate that the attractive signal downstream of Hmgcr operates over a long range and is sufficient to reach germ cells for the entirety of their migration. Furthermore, Hmgcr-mediated attraction and Wunen-mediated repulsion can operate simultaneously ruling out a model in which these pathways operate consecutively. Indeed, we show that Hmgcr-mediated attraction is boosted by Wunens suggesting the action of these two pathways is linked. Lastly, several papers have pointed to the secreted molecule Hedgehog (Hh) as being the germ cell attractant, whose secretion is increased by hmgcr. In this paper, we provide evidence that Hh is not downstream of hmgcr in germ cell migration.

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Gene trap analysis of germ cell signaling to Sertoli cells: NGF-TrkA mediated induction of Fra1 and Fos by post-meiotic germ cells

Journal of Cell Science ◽

10.1242/jcs.114.2.435 ◽

2001 ◽

Vol 114 (2) ◽

pp. 435-443 ◽

Cited By ~ 2

Author(s):

F. Vidal ◽

P. Lopez ◽

L.A. Lopez-Fernandez ◽

F. Ranc ◽

J.C. Scimeca ◽

...

Keyword(s):

Germ Cell ◽

Germ Cells ◽

Cross Talk ◽

Sertoli Cells ◽

Target Genes ◽

Fusion Transcript ◽

Cell Types ◽

Genomic Region ◽

Gene Encoding ◽

Gene Trapping

Analysis of complex signalisation networks involving distinct cell types is required to understand most developmental processes. Differentiation of male germ cells in adult mammals involves such a cross-talk between Sertoli cells, the somatic component which supports and controls germinal differentiation, and germ cells at their successive maturation stages. We developed a gene trapping strategy to identify genes, which, in Sertoli cells, are either up- or down-regulated by signals emitted by the germinal component. A library of approximately 2,000 clones was constituted from colonies independently selected from the Sertoli line 15P-1 by growth in drug-containing medium after random integration of a promoter-less (beta)geo transgene (neo(r)-lacZ fusion), which will be expressed as a fusion transcript from a ‘trapped’ cellular promoter, different in each clone. A first screen conducted on 700 events identified six clones in which beta-galactosidase activity was increased and one in which it was repressed upon addition of germ cells. The targeted loci were identified by cloning and sequencing the genomic region 5′ of the insert. One of them was identified as the gene encoding Fra1, a component of the AP1 transcription regulatory complex. Accumulation of Fra1 mRNA was induced, both in 15P-1 and in freshly explanted Sertoli cells, by addition of either round spermatids or nerve growth factor (NGF). The effect of NGF was mediated by the TrkA receptor and the ERK1-ERK2 kinase kinase pathway. Fos and Fra1 transcription were induced within the first hour after addition of the neurotrophin, but, unlike what is observed after serum induction in the same cells, a second wave of transcription of Fra1, but not of Fos, started 16 hours later and peaked at higher levels at about 20 hours. These results suggest that AP1 activation may be an important relay in the Sertoli-germ cell cross-talk, and validate the gene trapping approach as a tool for the identification of target genes in cell culture systems.

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Cell-type-specific regulation of genes involved in testicular lipid metabolism: fatty acid-binding proteins, diacylglycerol acyltransferases, and perilipin 2

Reproduction ◽

10.1530/rep-13-0199 ◽

2013 ◽

Vol 146 (5) ◽

pp. 471-480 ◽

Cited By ~ 16

Author(s):

Gerardo M Oresti ◽

Jesús García-López ◽

Marta I Aveldaño ◽

Jesús del Mazo

Keyword(s):

Fatty Acid ◽

Cell Differentiation ◽

Germ Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Fatty Acid Binding Proteins ◽

Cell Type ◽

Fatty Acid Binding ◽

Germ Cell Differentiation ◽

Perilipin 2

Male germ cell differentiation entails the synthesis and remodeling of membrane polar lipids and the formation of triacylglycerols (TAGs). This requires fatty acid-binding proteins (FABPs) for intracellular fatty acid traffic, a diacylglycerol acyltransferase (DGAT) to catalyze the final step of TAG biosynthesis, and a TAG storage mode. We examined the expression of genes encoding five members of the FABP family and two DGAT proteins, as well as the lipid droplet protein perilipin 2 (PLIN2), during mouse testis development and in specific cells from seminiferous epithelium.Fabp5expression was distinctive of Sertoli cells and consequently was higher in prepubertal than in adult testis. The expression ofFabp3increased in testis during postnatal development, associated with the functional differentiation of interstitial cells, but was low in germ cells.Fabp9, together withFabp12, was prominently expressed in the latter. Their transcripts increased from spermatocytes to spermatids and, interestingly, were highest in spermatid-derived residual bodies (RB). Both Sertoli and germ cells, which produce neutral lipids and store them in lipid droplets, expressedPlin2. Yet, whileDgat1was detected in Sertoli cells,Dgat2accumulated in germ cells with a similar pattern of expression asFabp9. These results correlated with polyunsaturated fatty acid-rich TAG levels also increasing with mouse germ cell differentiation highest in RB, connecting DGAT2 with the biosynthesis of such TAGs. The age- and germ cell type-associated increases inFabp9,Dgat2, andPlin2levels are thus functionally related in the last stages of germ cell differentiation.

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Minireview: Transcriptional Regulation of Gonadal Development and Differentiation

Endocrinology ◽

10.1210/en.2004-1454 ◽

2005 ◽

Vol 146 (3) ◽

pp. 1035-1042 ◽

Cited By ~ 60

Author(s):

Susan Y. Park ◽

J. Larry Jameson

Keyword(s):

Germ Cells ◽

Sertoli Cells ◽

Leydig Cells ◽

Cell Types ◽

Gonadal Development ◽

Targeted Mutagenesis ◽

Seminiferous Tubules ◽

Molecular Pathways ◽

Theca Cells ◽

Main Cell

The embryonic gonad is undifferentiated in males and females until a critical stage when the sex chromosomes dictate its development as a testis or ovary. This binary developmental process provides a unique opportunity to delineate the molecular pathways that lead to distinctly different tissues. The testis comprises three main cell types: Sertoli cells, Leydig cells, and germ cells. The Sertoli cells and germ cells reside in seminiferous tubules where spermatogenesis occurs. The Leydig cells populate the interstitial compartment and produce testosterone. The ovary also comprises three main cell types: granulosa cells, theca cells, and oocytes. The oocytes are surrounded by granulosa and theca cells in follicles that grow and differentiate during characteristic reproductive cycles. In this review, we summarize the molecular pathways that regulate the distinct differentiation of these cell types in the developing testis and ovary. In particular, we focus on the transcription factors that initiate these cascades. Although most of the early insights into the sex determination pathway were based on human mutations, targeted mutagenesis in mouse models has revealed key roles for genes not anticipated to regulate gonadal development. Defining these molecular pathways provides the foundation for understanding this critical developmental event and provides new insight into the causes of gonadal dysgenesis.

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Studies of Sl/Sld in equilibrium with +/+ mouse aggregation chimaeras. II. Effect of the steel locus on spermatogenesis

Development ◽

10.1242/dev.102.1.117 ◽

1988 ◽

Vol 102 (1) ◽

pp. 117-126 ◽

Cited By ~ 2

Author(s):

H. Nakayama ◽

H. Kuroda ◽

H. Onoue ◽

J. Fujita ◽

Y. Nishimune ◽

...

Keyword(s):

Mast Cells ◽

Germ Cell ◽

Germ Cells ◽

Cross Sections ◽

Sertoli Cells ◽

Type A ◽

Precursor Cells ◽

Intrinsic Defect ◽

Serial Sections ◽

Type A Spermatogonia

Mutant mice of Sl/Sld genotype are deficient in melanocytes, erythrocytes, mast cells and germ cells. Deficiency of melanocytes, erythrocytes and mast cells is not attributable to an intrinsic defect in their precursor cells but to a defect in the tissue environment that is necessary for migration, proliferation and/or differentiation. We investigated the mechanism of germ cell deficiency in male Sl/Sld mice by producing aggregation chimaeras from Sl/Sld and +/+ embryos. Chimaeric mice with apparent white stripes were obtained. Two of four such chimaeras were fertile and the phenotypes of resulting progenies showed that some Sl/Sld germ cells had differentiated into functioning sperms in the testis of the chimaeras. In cross sections of the testes of chimaeras, both differentiated and nondifferentiated tubules were observed. However, the proportions of type A spermatogonia to Sertoli cells in both types of tubules were comparable to the values observed in differentiated tubules of normal +/+ mice. We reconstructed the whole length of four tubules from serial sections. Differentiated and nondifferentiated segments alternated in a single tubule. The shortest differentiated segment contained about 180 Sertoli cells and the shortest nondifferentiated segment about 150 Sertoli cells. These results suggest that Sertoli cells of either Sl/Sld or +/+ genotype make discrete patches and that differentiation of type A spermatogonia does not occur in patches of Sl/Sld Sertoli cells.

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Hepatocyte growth factor modulates in vitro survival and proliferation of germ cells during postnatal testis development

Journal of Endocrinology ◽

10.1677/joe.1.06528 ◽

2006 ◽

Vol 189 (1) ◽

pp. 137-146 ◽

Cited By ~ 11

Author(s):

A Catizone ◽

G Ricci ◽

J Del Bravo ◽

M Galdieri

Keyword(s):

Growth Factor ◽

Hepatocyte Growth Factor ◽

Germ Cell ◽

Germ Cells ◽

Cell Types ◽

Tyrosine Kinase Receptor ◽

Testis Development ◽

Pachytene Spermatocytes ◽

Hepatocyte Growth

The hepatocyte growth factor (HGF) is a pleiotropic cytokine that influences mitogenesis, motility and differentiation of many different cell types by its tyrosine kinase receptor c-Met. We previously demonstrated that the c-Met/HGF system is present and functionally active during postnatal testis development. We found also that spermatozoa express c-Met and that HGF has a positive effect on the maintenance of sperm motility. In the present paper, we extend our study on the germ cells at different stages of differentiation during the postnatal development of the testis. We demonstrate that c-met is present in rat spermatogonia, pachytene spermatocytes and round spermatids and that HGF significantly increases spermatogonial proliferation in 8- to 10-day-old pre-pubertal rats. At this age HGF does not affect Sertoli cells and peritubular myoid cells proliferation. In addition, we studied the effect of the factor on germ cell apoptosis and we show that HGF prevents the germ cell apoptotic process. We also studied the effect of HGF on 18- to 20-day-old and 28- to 30-day-old rat testes. At these ages also the factor significantly increases germ cell duplication and decreases the number of apoptotic cells. However, the effect on programmed cell death is higher in the 8- to 10-day-old rats and declines in the older animals. In conclusion, we report that rat germ cells (spermatogonia, pachytene spermatocytes and round spermatids) express c-met and that HGF modulates germ cell proliferating activity and apoptosis in vitro. These data indicate that the c-Met/HGF system is involved in male germ cell homeostasis and, consequently, has a role in male fertility.

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Sertoli cell ablation and replacement of the spermatogonial niche in mouse

Nature Communications ◽

10.1038/s41467-019-13879-8 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 5

Author(s):

Tetsuhiro Yokonishi ◽

Jennifer McKey ◽

Shintaro Ide ◽

Blanche Capel

Keyword(s):

Sertoli Cells ◽

Cell Types ◽

Supporting Cell ◽

Idiopathic Male Infertility ◽

Testicular Cells ◽

Cell Ablation ◽

Toxic Drug ◽

Donor Cells ◽

Multiple Cell

AbstractSpermatogonia, which produce sperm throughout the male lifetime, are regulated inside a niche composed of Sertoli cells, and other testis cell types. Defects in Sertoli cells often lead to infertility, but replacement of defective cells has been limited by the inability to deplete the existing population. Here, we use an FDA-approved non-toxic drug, benzalkonium chloride (BC), to deplete testis cell types in vivo. Four days after BC administration, Sertoli cells are preferentially depleted, and can be replaced to promote spermatogenesis from surviving (host) spermatogonia. Seven days after BC treatment, multiple cell types can be engrafted from fresh or cryopreserved testicular cells, leading to complete spermatogenesis from donor cells. These methods will be valuable for investigation of niche-supporting cell interactions, have the potential to lead to a therapy for idiopathic male infertility in the clinic, and could open the door to production of sperm from other species in the mouse.

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Expression Profiling of Mammalian Male Meiosis and Gametogenesis Identifies Novel Candidate Genes for Roles in the Regulation of Fertility

Molecular Biology of the Cell ◽

10.1091/mbc.e03-10-0762 ◽

2004 ◽

Vol 15 (3) ◽

pp. 1031-1043 ◽

Cited By ~ 97

Author(s):

Ulrich Schlecht ◽

Philippe Demougin ◽

Reinhold Koch ◽

Leandro Hermida ◽

Christa Wiederkehr ◽

...

Keyword(s):

Germ Cell ◽

Germ Cells ◽

Expression Profiling ◽

Large Scale ◽

Developmental Stages ◽

Expression Patterns ◽

Control Cell ◽

Cell Types ◽

Male Meiosis ◽

Cell Expression

We report a comprehensive large-scale expression profiling analysis of mammalian male germ cells undergoing mitotic growth, meiosis, and gametogenesis by using high-density oligonucleotide microarrays and highly enriched cell populations. Among 11,955 rat loci investigated, 1268 were identified as differentially transcribed in germ cells at subsequent developmental stages compared with total testis, somatic Sertoli cells as well as brain and skeletal muscle controls. The loci were organized into four expression clusters that correspond to somatic, mitotic, meiotic, and postmeiotic cell types. This work provides information about expression patterns of ∼200 genes known to be important during male germ cell development. Approximately 40 of those are included in a group of 121 transcripts for which we report germ cell expression and lack of transcription in three somatic control cell types. Moreover, we demonstrate the testicular expression and transcriptional induction in mitotic, meiotic, and/or postmeiotic germ cells of 293 as yet uncharacterized transcripts, some of which are likely to encode factors involved in spermatogenesis and fertility. This group also contains potential germ cell-specific targets for innovative contraceptives. A graphical display of the data is conveniently accessible through the GermOnline database at http://www.germonline.org .

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