TSPY1 suppresses USP7-mediated p53 function and promotes spermatogonial proliferation

The present study describes the testicular maturation phases (associating the germ cells development and the morphological changes suffered by the germinal epithelium along the whole year), and the testicular morphology in the yellow peacock bass Cichla kelberi, relating it to other species. For this purpose, 78 specimens were studied according conventional techniques of light microscope. The testes in C. kelberi were classified as unrestricted spermatogonial lobular, an apomorphic characteristic in the recent groups of Teleost. Furthermore, were defined five testicular maturation phases: Preparatory phase; Early Germinal Epithelium Development; Mid Germinal Epithelium Development; Late Germinal Epithelium Development and; Regression. Similar classifications were described to other species indicating that the testicular classifications based on this propose, can be applied to lots of fishes. However, besides it similarity, the testicular reproductive cycle of C. kelberifollows a different pattern in the Regression phase, on which the gonadal restructuration and the spermatogonial proliferation gathers at the same time. So, the testes in C. kelberi never return to the Preparatory phase to start a new reproductive cycle, being this one present only at the first reproductive cycle in this species. This fact also explains the absence of individuals totally spent after their first reproductive cycle.

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Epidermal growth factor mediates spermatogonial proliferation in newt testis

Reproductive Biology and Endocrinology ◽

10.1186/1477-7827-6-7 ◽

2008 ◽

Vol 6 (1) ◽

Cited By ~ 15

Author(s):

Keisuke Abé ◽

Ko Eto ◽

Shin-ichi Abé

Keyword(s):

Growth Factor ◽

Epidermal Growth Factor ◽

Epidermal Growth ◽

Spermatogonial Proliferation

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The c-kit receptor protein in the testis of green frog Rana esculenta: seasonal changes in relationship to testosterone titres and spermatogonial proliferation

Reproduction ◽

10.1530/rep.1.01009 ◽

2007 ◽

Vol 133 (1) ◽

pp. 51-60 ◽

Cited By ~ 22

Author(s):

Franca Raucci ◽

Maria Maddalena Di Fiore

Keyword(s):

Germ Cell ◽

Mitotic Activity ◽

Rana Esculenta ◽

Reproductive Period ◽

Receptor Protein ◽

Germinal Epithelium ◽

Positive Staining ◽

Green Frog ◽

Cyclic Changes ◽

Spermatogonial Proliferation

The green frogRana esculentais a seasonal breeder. The cyclic changes between almost arrested and highly activated spermatogenesis offer an ideal model to study basic mechanisms of spermatogenesis. In this study, we demonstrated, to our knowledge for the first time,c-kitreceptor positive cells in the testis of this amphibian. The presence ofc-kitreceptor protein was confirmed by western blotting (Wb) analyses carried out in the testis during all the three main phases of the sexual cycle. The antibody recognized a band of about 150 kDa that was correlated with the positive staining in the germinal epithelium. The immunolabelling forc-kitreceptor, evaluated by immunohistochemistry (IHC), was localized in I and II spermatogonia (SPG), in I and II spermatocytes, in both elongating spermatids and spermatozoa and in the Leydig cells. Furthermore,c-kitexpression showed a seasonal pattern connected with both testicular and plasma profiles of testosterone during the reproductive cycle. The highest expression ofc-kitreceptor occurred during the reproductive period, when the testis exhibited the maximum concentration of testosterone. In this period, the mitotic activity of germ cell, assessed by both Wb and IHC analyses for proliferating cell nuclear antigen (PCNA), was intensive. Indeed, during the post-reproductive period, testosterone titres were the lowest and the expression of both PCNA andc-kitreceptor protein in the testis, although present, is minor when compared with the reproductive phase. This evidence suggests that cell division can continue sufficiently to accumulate SPG for the next spring, when new germinal cells undergo multiplication. Finally, during the pre-reproductive period, testosterone levels begin to increase and mitotic activity of germinal epithelium is comparably enhanced. These events seem to precede the period of maximum stimulated spermatogonial proliferation, i.e. the reproductive period. These results suggest that thec-kitreceptor may play a role in germ cell proliferation and provide a basis for future detailed investigation of regulatory factors of the proliferation of SPG.

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Fsh Stimulates Spermatogonial Proliferation and Differentiation in Zebrafish via Igf3

Endocrinology ◽

10.1210/en.2015-1157 ◽

2015 ◽

Vol 156 (10) ◽

pp. 3804-3817 ◽

Cited By ~ 66

Author(s):

Rafael Henrique Nóbrega ◽

Roberto Daltro Vidal de Souza Morais ◽

Diego Crespo ◽

Paul P. de Waal ◽

Luiz Renato de França ◽

...

Keyword(s):

Mitotic Index ◽

Germ Line ◽

Type A ◽

Single Type ◽

Dependent Manner ◽

Independent Manner ◽

Proliferation And Differentiation ◽

Igf Receptor ◽

Receptor Inhibitor ◽

Spermatogonial Proliferation

Growth factors modulate germ line stem cell self-renewal and differentiation behavior. We investigate the effects of Igf3, a fish-specific member of the igf family. Fsh increased in a steroid-independent manner the number and mitotic index of single type A undifferentiated spermatogonia and of clones of type A differentiating spermatogonia in adult zebrafish testis. All 4 igf gene family members in zebrafish are expressed in the testis but in tissue culture only igf3 transcript levels increased in response to recombinant zebrafish Fsh. This occurred in a cAMP/protein kinase A-dependent manner, in line with the results of studies on the igf3 gene promoter. Igf3 protein was detected in Sertoli cells. Recombinant zebrafish Igf3 increased the mitotic index of type A undifferentiated and type A differentiating spermatogonia and up-regulated the expression of genes related to spermatogonial differentiation and entry into meiosis, but Igf3 did not modulate testicular androgen release. An Igf receptor inhibitor blocked these effects of Igf3. Importantly, the Igf receptor inhibitor also blocked Fsh-induced spermatogonial proliferation. We conclude that Fsh stimulated Sertoli cell production of Igf3, which promoted via Igf receptor signaling spermatogonial proliferation and differentiation and their entry into meiosis. Because previous work showed that Fsh also released spermatogonia from an inhibitory signal by down-regulating anti-Müllerian hormone and by stimulating androgen production, we can now present a model, in which Fsh orchestrates the activity of stimulatory (Igf3, androgens) and inhibitory (anti-Müllerian hormone) signals to promote spermatogenesis.

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Salinity and photoperiod modulate pubertal development in Atlantic salmon (Salmo salar)

Journal of Endocrinology ◽

10.1530/joe-13-0240 ◽

2013 ◽

Vol 220 (3) ◽

pp. 319-332 ◽

Cited By ~ 27

Author(s):

Michelle C Melo ◽

Eva Andersson ◽

Per Gunnar Fjelldal ◽

Jan Bogerd ◽

Luiz R França ◽

...

Keyword(s):

Atlantic Salmon ◽

Salmo Salar ◽

Plasma Levels ◽

Pubertal Development ◽

Mrna Levels ◽

Treatment Groups ◽

Timing Of Puberty ◽

The Brain ◽

Spermatogonial Proliferation ◽

Stimulation Of

The Atlantic salmon shows substantial life cycle plasticity, which also applies to the timing of puberty. While it is characterized by the activation of the brain–pituitary–gonad axis, many morphophysiological aspects of puberty and the influence of environmental conditions, such as water salinity, are not well understood in fish. Here, 12-month-old Atlantic salmon coming from an out-of-season smoltification regime in December were exposed to freshwater (FW) or seawater (SW) at 16 °C to stimulate puberty under a 24-h constant light (LL) or 12 h light:12 h darkness (LD) photoperiod. These four treatment groups (FWLL, SWLL, FWLD, and SWLD) were studied from January to March. Next to 11-ketotestosterone (11-KT) plasma levels, the expression of pituitary genes (gnrhr4, fshb, and lhb) and spermatogenesis was quantified. When spermatogonial proliferation started, fshb mRNA levels increased steeply and began to decrease when spermatogonial mitosis approached completion and most germ cells had reached meiotic or post-meiotic stages. Conversely, lhb mRNA levels increased progressively during spermatogenesis. Most males in all treatment groups matured, but exposure to SW resulted in the strongest stimulation of the onset of spermatogenesis and elevation of pituitary gnrhr4 and fshb mRNA levels. Later on, the LD photoperiod accelerated, irrespective of the salinity, the completion of spermatogenesis, associated with higher lhb mRNA and 11-KT plasma levels than in the LL groups. We find that both salinity and photoperiod modulated different aspects of spermatogenesis, and resulted in a differential activation of pituitary and testis functions; SW stimulating the onset and the shorter photoperiod the completion of spermatogenesis.

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The arrangement of germ cells in the rat seminiferous tubule: an electron-microscope study

Journal of Cell Science ◽

10.1242/jcs.19.3.487 ◽

1975 ◽

Vol 19 (3) ◽

pp. 487-507

Author(s):

P.B. Moens ◽

A.D. Hugenholtz

Keyword(s):

Electron Microscopy ◽

Germ Cells ◽

Electron Microscope Study ◽

Mitotic Cycle ◽

Seminiferous Epithelium ◽

Serial Sections ◽

Cell Numbers ◽

Large Size ◽

Cytoplasmic Bridges ◽

Spermatogonial Proliferation

The spermatogonia and early spermatocytes of 13 samples of rat seminiferous epithelium (about 0-05 mm2 each) were mapped from electron micrographs of serial sections. Clones of cells, connected by cytoplasmic bridges (syncytia of 2–100 cells), in various stages of spermatogenic development were identified. Maps of 7 separate areas are illustrated. It is concluded that, contrary to the models of spermatogonial proliferation based on light-microscope observations, regions of seminiferous epithelium which are identical in terms of spermatid and spermatocyte criteria have, in fact, quantitative and qualitative differences in their spermatogonial population. The data are interpreted that for a given epithelial area there is a periodic build-up of spermatogonia which then produce several successive quanta of spermatocytes and when the spermatogonia are depleted the process repeats. That cell numbers less than double following a mitotic cycle has generally been attributed to systematic degeneration. Evidence from electron microscopy indicates, however, that at the mitotic peaks not all the syncytia undergo division but that some remain arrested. Similarly, within a dividing syncytium a few cells do not divide while they advance developmentally with the syncytium as a whole. The observed large size of spermatocyte syncytia further argues against systematic degeneration with its attendant fragmentation of syncytia.

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