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

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.

2008 ◽  
Vol 20 (1) ◽  
pp. 223
Author(s):  
J. Luo ◽  
S. Megee ◽  
I. Dobrinski

During mammalian spermatogenesis, spermatogonial stem cells (SSCs) reside in the stem cell niche on the basement membrane where they undergo self-renewing divisions. Differentiating daughter cells are located progressively more toward the tubular lumen where they ultimately form spermatozoa. The mechanisms responsible for maintenance of SSCs at the basement membrane are unclear. Microtubules consisting of α/β-tubulin heterodimers are associated with many cellular functions. Reversible acetylation of α-tubulin at Lys40 has been implicated in regulating microtubule stability and function. Acetylation of α-tubulin is abundant in stable microtubules but absent from dynamic cellular structures. Deacetylation of α-tubulin is controlled by histone deacetylase 6 which is predominantly expressed in mouse testis. Here, we tested the hypothesis that differential acetylation of α-tubulin might be involved in maintenance of SSCs. Immunohistochemistry for acetylated α-tubulin (Ac-α-Tu) and the spermatogonia specific proteins PGP 9.5, DAZL, and PLZF were used to characterize the expression pattern of Ac-α-Tu in porcine and murine germ cells at different stages of testis development. In immature boar testes, Ac-α-Tu was present exclusively in gonocytes but not in other testicular cells at 1 week of age, and in a subset of spermatogonia at 10 weeks of age. At this age, spermatogonia are migrating to the basement membrane of the seminiferous tubules, and Ac-α-Tu appeared to be polarized toward the basement membrane. In immature mouse testes, Ac-α-Tu was present in germ cells and Sertoli cells at 6 days of age, whereas at 2 weeks of age, Ac-α-Tu expression was stronger in spermatogonia co-expressing PGP 9.5 and in spermatocytes than in Sertoli cells or PGP 9.5-negative spermatogonia. In adult boar and mouse testes, Ac-α-Tu was detected in a few single or paired spermatogonia expressing PGP 9.5 localized on the basement membrane as well as in spermatocytes, spermatids, and spermatozoa. Spermatogonia with high levels of Ac-α-Tu expressed PLZF but did not express DAZL, suggesting that only undifferentiated spermatogonia maintain a high level of Ac-α-Tu. When seminiferous tubules from 1-week-old and adult boar testes were maintained in vitro for 1–2 days, high levels of Ac-α-Tu were detected in single or paired round spermatogonia with a large nucleus, compared to low levels in elongated paired and aligned spermatogonia. The unique expression pattern of Ac-α-Tu in undifferentiated germ cells during postnatal development appears to be conserved in mammalian testes. Since Ac-α-Tu is a component of long-lived stable microtubules and reducing acetylation of α-tubulin enhances cell motility, these results suggest that stabilization of microtubules might contribute to the maintenance of spermatogonial stem cells. This work was supported by 1R01 RR 17359-05.


Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1759-1766 ◽  
Author(s):  
K. Yomogida ◽  
H. Ohtani ◽  
H. Harigae ◽  
E. Ito ◽  
Y. Nishimune ◽  
...  

GATA-1 is an essential factor for the transcriptional activation of erythroid-specific genes, and is also abundantly expressed in a discrete subset of cells bordering the seminiferous epithelium in tubules of the murine testis. In examining normal and germ-line defective mutant mice, we show here that GATA-1 is expressed only in the Sertoli cell lineage in mouse testis. GATA-1 expression in Sertoli cells is induced concomitantly with the first wave of spermatogenesis, and GATA-1-positive cells are uniformly distributed among all tubules during prepubertal testis development. However, the number of GATA-1-positive cells declines thereafter and were found only in the peripheral zone of seminiferous tubules in stages VII, VIII and IX of spermatogenesis in the adult mouse testis. In contrast, virtually every Sertoli cell in mutant W/Wv, jsd/jsd or cryptorchid mice (all of which lack significant numbers of germ cells) expresses GATA-1, thus showing that the expression of this transcription factor is negatively controlled by the maturing germ cells. These observations suggest that transcription factor GATA-1 is a developmental stage- and spermatogenic cycle-specific regulator of gene expression in Sertoli cells.


2013 ◽  
Vol 25 (1) ◽  
pp. 290 ◽  
Author(s):  
R. H. Powell ◽  
M. N. Biancardi ◽  
J. Galiguis ◽  
Q. Qin ◽  
C. E. Pope ◽  
...  

Spermatogonial stem cells (SSC), progenitor cells capable of both self-renewal and producing daughter cells that will differentiate into sperm, can be manipulated for transplantation to propagate genetically important males. This application was demonstrated in felids by the successful xeno-transplantation of ocelot mixed germ cells into the testes of domestic cats, which resulted in the production of ocelot sperm (Silva et al. 2012 J. Androl. 33, 264–276). Spermatogonial stem cells are in low numbers in the testis, but have been identified and isolated in different mammalian species using SSC surface markers; however, their expression varies among species. Until recently, little was known about the expression of SSC surface markers in feline species. We previously demonstrated that many mixed germ cells collected from adult cat testes express the germ cell markers GFRα1, GPR125, and C-Kit, and a smaller population of cells expresses the pluripotent SSC-specific markers SSEA-1 and SSEA-4 (Powell et al. 2011 Reprod. Fertil. Dev. 24, 221–222). In the present study, our goal was to identify germ cell and SSC-specific markers in SSC from cat testes. Immunohistochemical (IHC) localization of germ cell markers GFRα1, GPR125, and C-Kit and pluripotent SSC-specific markers SSEA-1, SSEA-4, TRA-1-60, TRA-1-81, and Oct-4 was detected in testis tissue from both sexually mature and prepubertal males. Testes were fixed with modified Davidson’s fixative for 24 h before processing, embedding, and sectioning. The EXPOSE Mouse and Rabbit Specific HRP/DAB detection IHC kit (Abcam®, Cambridge, MA, USA) was used for antibody detection. Staining for SSEA-1, SSEA-4, TRA-1-60, TRA-1-81, and Oct-4 markers was expressed specifically at the basement membrane of the seminiferous tubules in both adult and prepubertal testes. The GFRα1 and GPR125 markers were detected at the basement membrane of the seminiferous tubules and across the seminiferous tubule section. However, C-Kit was not detected in any cell. Using flow cytometry from a pool of cells from seven adult testes, we detected 45% GFRα1, 50% GPR125, 59% C-Kit, 18% TRA-1-60, 16% TRA-1-81 positive cells, and a very small portion of SSEA-1 (7%) and SSEA-4 (3%) positive cells. Dual staining of germ cells pooled from 3 testes revealed 3 distinct cell populations that were positive for GFRα1 only (23%), positive for both GFRα1 and SSEA-4 (6%), and positive for SSEA-4 only (1%). Our IHC staining of cat testes indicated that cells along the basement membrane of seminiferous tubules were positive for SSC-specific markers, and flow cytometry analysis revealed that there were different cell populations expressing both germ cell and SSC-specific markers. Flow cytometry results show overlapping germ cell populations expressing SSEA-4 and GFRα1, and IHC results reveal that SSEA-4 positive cells are spermatogonia, whereas GFRα1 positive cells include other stages of germ cells, indicating that the small population of cells positive only for SSEA-4 is undifferentiated cat SSC.


2003 ◽  
Vol 15 (6) ◽  
pp. 323 ◽  
Author(s):  
David Pei-Cheng Lin ◽  
Ming-Yu Chang ◽  
Bo-Yie Chen ◽  
Han-Hsin Chang

Research using stem cells has several applications in basic biology and clinical medicine. Recent advances in the establishment of male germ line stem cells provided researchers with the ability to identify, isolate, maintain, expand and differentiate the spermatogonia, the primitive male germ cells, as cell lines under in vitro conditions. The ability to culture and manipulate stem cell lines from male germ cells has gradually facilitated research into spermatogenesis and male infertility, to an extent beyond that facilitated by the use of somatic stem cells. After the introduction of exogenous genes, the spermatogonial cells can be transplanted into the seminiferous tubules of recipients, where the transplanted cells can contribute to the offspring. The present review concentrates on the origin, life cycle and establishment of stem cell lines from male germ cells, as well as the current status of transplantation techniques and the application of spermatogonial stem cell lines.


Stem Cells ◽  
2009 ◽  
Vol 27 (1) ◽  
pp. 68-77 ◽  
Author(s):  
Nathan Bucay ◽  
Mayra Yebra ◽  
Vincenzo Cirulli ◽  
Ivka Afrikanova ◽  
Thomas Kaido ◽  
...  

2015 ◽  
Vol 27 (1) ◽  
pp. 251
Author(s):  
M. Nowak-Imialek ◽  
N. Lachmann ◽  
D. Herrmann ◽  
F. Jacob ◽  
H. Niemann

Oct4 is a transcription factor essential for establishment and maintenance of pluripotency in mammalian stem cells. Oct4 expression was found in early embryos and germ cells throughout fetal development. In male mice, Oct4 expression is found in mitotically arrested prospermatogonia until birth. After onset of spermatogenesis, expression is maintained in type A spermatogonia, but is downregulated in type B spermatogonia and in spermatocytes (Pesce et al. 1998 Mech. Dev). Previously, we successfully generated Oct4-EGFP reporter pigs carrying the entire 18-kb genomic sequence of the murine Oct4 gene fused to the enhanced green fluorescent protein (EGFP) cDNA (Nowak-Imialek et al. 2011 Stem Cells Dev.). This animal model is unique because it allows in vivo and in vitro visualisation of Oct4-positive cells. Germ line specific Oct4-EGFP expression was analysed in testis isolated from young (<1 week) and adult (>7 months) pigs. Squash preparation of testicular tissue isolated from adult transgenic boars revealed high amounts of EGFP-positive cells compared to young piglets. We confirmed Oct4 and EGFP expression in the testis from young and adult transgenic animals using Northern blot analysis. Specific expression of Oct4 and EGFP in testis could be observed in blots as a single band of 1.5 kb. As a loading control, the blot was rehybridized with a β-actin probe. Mammalian testes contain different cell types, including germ cells, Sertoli cells, Leydig cells, and peritubular cells. To define the cellular origin of EGFP-expressing cells, we isolated these cells from adult transgenic testis using fluorescence-activated cell sorting (FACS)-based techniques. Analysis of isolated EGFP positive cells with qRT-PCR demonstrated the presence of marker genes specific for undifferentiated (Oct4, UTF1, FGFR3, PGP 9.5, THY-1, SALL4, and GFRα1) and differentiated (BOLL and PRM2) germ cells. Markers specific for Sertoli cells (vimentin) and Leydig cells (LHCGR) were not observed. To verify the localization of EGFP-positive cells in seminiferous tubules, we performed immunohistochemical detection of GFP in adult pig testis. Unlike the Oct4-EGFP reporter mouse model, GFP protein was not found in spermatogonia attached to the basement membrane of seminiferous tubules, but instead were found in differentiated germ cells, including spermatocytes and spermatids. These results show that the Oct4-EGFP expression in testis differs between mouse and porcine Oct4-EGFP transgenic models. To verify that the EGFP expression driven by the mouse Oct4 promoter in porcine testis reflects the endogenous Oct4 expression profile, Western blot and histochemical analyses are currently underway.


Science ◽  
2020 ◽  
Vol 367 (6479) ◽  
pp. 757-762 ◽  
Author(s):  
Timothy Q. DuBuc ◽  
Christine E. Schnitzler ◽  
Eleni Chrysostomou ◽  
Emma T. McMahon ◽  
Febrimarsa ◽  
...  

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.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 373-373
Author(s):  
Tatyana Kotova ◽  
Anastasia N Vetokh ◽  
Ludmila A Volkova ◽  
Natalia Volkova ◽  
Natalia A Zinovieva

Abstract The use of testicular stem cells (spermatogonia) is of most interest for obtaining individuals with predetermined traits and genome genetic modification and for conservation of poultry gene pool. A significant population of mature donor germ cells (sperm) is formed upon successful spermatogonia cells transplantation into the testes of male recipients. Obtained sperm can be used to produce offspring with the desired traits. A key step in this technology is the removal of own spermatogenic cells (inhibition of spermatogenesis) in male recipients. The aim of research was to develop and optimize methodological approaches to inhibit the spermatogenesis in quail using busulfan. This drug was injected directly into the testes parenchyma of mature males by multiple injection at the concentration from 20 to 100 mg per 1kg of body weight (n = 25). Histological preparations of testes from the experimental quails were obtained to study composition of spermatogenic cells in the seminiferous tubules after busulfan administration. The male peers who were not injected with busulfan were used as a control. Experimental quails showed a decrease in the number of spermatogenic cells in the seminiferous tubules 32, 75, 111, 119 and 118 times compared with the control when using busulfan in concentrations 20, 40, 60, 80 and 100 mg/kg of weight, respectively (P &lt; 0.001). The cells composition in the seminiferous tubules from experimental quails was represented mainly by Sertoli cells and spermatogonia. After busulfan introduction at the concentrations 20, 40, 60, 80 and 100 mg/kg, the percentage of spermatogonia was 55±5 %, 24±4 %, 6±2 %, 5±2 % and 4±1 %, respectively. The use of busulfan at the concentration of 80–100 mg/kg led to high mortality of quails. Thus, it was found that the optimal busulfan concentration for elimination of quail spermatogenic cells was 60 mg/kg. Supported by RFBR within Project №18-29-07079.


2021 ◽  
Vol 52 (6) ◽  
pp. 370-378
Author(s):  
A. Yu. Kulibin ◽  
E. A. Malolina

Abstract The rete testis connects seminiferous tubules in which germ cells develop to the efferent ducts and the epididymis, where gametes mature and gain mobility. Several recent studies have thoroughly explored the morphogenesis of this structure in mice during embryonic and postnatal periods. A part of the rete testis has been shown to derive from the precursors of gonad somatic cells before sex determination. The other part forms from embryonal Sertoli cells of testis cords adjacent to the mesonephros. The transformation of Sertoli cells into rete testis cells is apparently not limited to the embryonic stage of development and continues during postnatal testis development. Recently, it was found that the rete testis participates in the formation and maintenance of specialized Sertoli cells in terminal segments of seminiferous tubules, transitional zones. Current views suggest that the transitional zones of the seminiferous tubules may represent a niche for spermatogonial stem cells, the site of the prolonged proliferation of Sertoli cells in the pubertal and postpubertal periods of testis development, and also could be a generator of spermatogenic waves. To sum up, the rete testis transports gametes from the testis to the epididymis, maintains pressure within seminiferous tubules, regulates the composition of the testicular fluid, and impacts the spermatogenic process itself.


1994 ◽  
Vol 161 (2) ◽  
pp. 626-628 ◽  
Author(s):  
Colin L. Stewart ◽  
Inder Gadi ◽  
Harshida Bhatt

Sign in / Sign up

Export Citation Format

Share Document