Comparison of actin-filament bundles in myoid cells and Sertoli cells of the rat, golden hamster and mouse

1994 ◽  
Vol 275 (2) ◽  
pp. 395-398 ◽  
Author(s):  
Mamiko Maekawa ◽  
Toshio Nagano ◽  
Tohru Murakami
Keyword(s):  
Actin Filament ◽  
Sertoli Cells ◽  
Golden Hamster ◽  
Myoid Cells ◽  
Filament Bundles

Distribution of actin-filament bundles in myoid cells, Sertoli cells, and tunica albuginea of rat and mouse testes

1991 ◽  
Vol 266 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Mamiko Maekawa ◽  
Toshio Nagano ◽  
Kyoko Kamimura ◽  
Tohru Murakami ◽  
Harunori Ishikawa ◽  
...  
Keyword(s):  
Actin Filament ◽  
Sertoli Cells ◽  
Tunica Albuginea ◽  
Myoid Cells ◽  
Filament Bundles

scholarly journals rpS6 Regulates Blood-Testis Barrier Dynamics By Affecting F-Actin Organization and Protein Recruitment

Endocrinology ◽  
2012 ◽  
Vol 153 (10) ◽  
pp. 5036-5048 ◽  
Author(s):  
Ka-Wai Mok ◽  
Dolores D. Mruk ◽  
Bruno Silvestrini ◽  
C. Yan Cheng
Keyword(s):  
Sertoli Cell ◽  
Actin Filament ◽  
Sertoli Cells ◽  
Plasma Membranes ◽  
Permeability Barrier ◽  
Actin Organization ◽  
Filament Bundles ◽  
Mtorc1 Pathway ◽  
Protein Recruitment ◽  
Blood Testis Barrier

Abstract During spermatogenesis, preleptotene spermatocytes residing near the basement membrane of the seminiferous tubule must traverse the blood-testis barrier (BTB) at stage VIII–IX of the epithelial cycle to continue their development in the adluminal compartment. Unlike other blood-tissue barriers (e.g. the blood-brain barrier) that are created by the endothelial tight junction (TJ) barrier of capillaries, the BTB is created by specialized junctions between Sertoli cells in which TJ coexists with basal ectoplasmic specialization (basal ES, a testis-specific adherens junction). The basal ES is typified by the presence of tightly packed actin filament bundles sandwiched between cisternae of endoplasmic reticulum and the apposing plasma membranes of Sertoli cells. These actin filament bundles also confer unusual adhesive strength to the BTB. Yet the mechanisms by which these filamentous actin (F-actin) networks are regulated from the bundled to the debundled state to facilitate the transit of spermatocytes remain elusive. Herein, we provide evidence that ribosomal protein S6 (rpS6), the downstream signaling molecule of the mammalian target of rapamycin complex 1 (mTORC1) pathway, is a major regulator of F-actin organization and adhesion protein recruitment at the BTB. rpS6 is restrictively and spatiotemporally activated at the BTB during the epithelial cycle. An activation of rpS6 led to a disruption of the Sertoli cell TJ barrier and BTB integrity. Its silencing in vitro or in vivo by using small interfering RNA duplexes or short hairpin RNA was found to promote the Sertoli cell TJ permeability barrier by the recruitment of adhesion proteins (e.g. claudin-11 and occludin) to the BTB. Thus, rpS6 in the mTORC1 pathway regulates BTB restructuring via its effects on the F-actin organization and protein recruitment at the BTB.

scholarly journals αE-catenin actin-binding domain alters actin filament conformation and regulates binding of nucleation and disassembly factors

2013 ◽  
Vol 24 (23) ◽  
pp. 3710-3720 ◽  
Author(s):  
Scott D. Hansen ◽  
Adam V. Kwiatkowski ◽  
Chung-Yueh Ouyang ◽  
HongJun Liu ◽  
Sabine Pokutta ◽  
...  
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Binding Domain ◽  
Actin Binding ◽  
Filamentous Actin ◽  
Filament Structure ◽  
Actin Binding Domain ◽  
Filament Bundles ◽  
Underlying Mechanisms ◽  
Cell Cell

The actin-binding protein αE-catenin may contribute to transitions between cell migration and cell–cell adhesion that depend on remodeling the actin cytoskeleton, but the underlying mechanisms are unknown. We show that the αE-catenin actin-binding domain (ABD) binds cooperatively to individual actin filaments and that binding is accompanied by a conformational change in the actin protomer that affects filament structure. αE-catenin ABD binding limits barbed-end growth, especially in actin filament bundles. αE-catenin ABD inhibits actin filament branching by the Arp2/3 complex and severing by cofilin, both of which contact regions of the actin protomer that are structurally altered by αE-catenin ABD binding. In epithelial cells, there is little correlation between the distribution of αE-catenin and the Arp2/3 complex at developing cell–cell contacts. Our results indicate that αE-catenin binding to filamentous actin favors assembly of unbranched filament bundles that are protected from severing over more dynamic, branched filament arrays.

scholarly journals Regulation of GDNF expression in Sertoli cells

Reproduction ◽  
2019 ◽  
Author(s):  
Parag Parekh ◽  
Thomas Xavier Garcia ◽  
Marie-claude Hofmann
Keyword(s):  
Germ Cell ◽  
Sertoli Cells ◽  
Seminiferous Tubules ◽  
Receptor Complex ◽  
Myoid Cells ◽  
Self Renewal ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Direct Cell ◽  
Ability To Drive

Sertoli cells regulate male germ cell proliferation and differentiation and are a critical component of the spermatogonial stem cell (SSC) niche, where homeostasis is maintained by the interplay of several signaling pathways and growth factors. These factors are secreted by Sertoli cells located within the seminiferous epithelium, and by interstitial cells residing between the seminiferous tubules. Sertoli cells and peritubular myoid cells produce glial cell line-derived neurotrophic factor (GDNF), which binds to the RET/GFRA1 receptor complex at the surface of undifferentiated spermatogonia. GDNF is known for its ability to drive SSC self-renewal and proliferation of their direct cell progeny. Even though the effects of GDNF are well studied, our understanding of the regulation its expression is still limited. The purpose of this review is to discuss how GDNF expression in Sertoli cells is modulated within the niche, and how these mechanisms impact germ cell homeostasis.

Mesonephric contribution to testis differentiation in the fetal mouse

Development ◽  
1993 ◽  
Vol 117 (1) ◽  
pp. 273-281 ◽  
Author(s):  
M. Buehr ◽  
S. Gu ◽  
A. McLaren
Keyword(s):  
Germ Cells ◽  
Sertoli Cells ◽  
Interstitial Cell ◽  
Mouse Embryos ◽  
Myoid Cells ◽  
Testis Differentiation ◽  
Embryonic Limb ◽  
Female Donor ◽  
Well Differentiated ◽  
Donor Embryo

Testes from 11.5-day-old mouse embryos, with and without attached mesonephroi, were cultured for 7 days. Isolated testes failed to develop well-differentiated testis cords: however, when cultured attached to a mesonephros from either a male or a female donor embryo, testes developed cords that were normal in appearance. Testes cultured next to a mesonephric region but separated from it by a permeable filter, did not develop normal cords, nor did testes grafted to fragments of embryonic limb or heart. When testes were grafted to mesonephric regions from mice carrying a transgenic marker, the marker was found in some of the peritubular myoid cells and other interstitial cells of the testis, but not in the Sertoli cells or the germ cells. We conclude that after 11.5 days post coitum, cells can migrate from the mesonephric region into the differentiating testis and can contribute to the interstitial cell population, and that this contribution is necessary for the establishment of normal cord structure. The germ cells in all cultured testes, whether or not differentiated cords were present, were T1 prospermatogonia: no meiotic germ cells were seen.

Expression of nerve growth factor and neurotrophin receptors in testicular cells suggest novel roles for neurotrophins outside the nervous system

1996 ◽  
Vol 8 (7) ◽  
pp. 1075 ◽  
Author(s):  
K Seidl ◽  
A Buchberger ◽  
C Erck
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Expression Patterns ◽  
Myoid Cells ◽  
Nerve Growth ◽  
High Affinity ◽  
Ngf Receptor

The present study was designed to clarify the non-neurotrophic role for neurotrophins in mouse testis. By means of SI nuclease protection assay we could demonstrate that the gene coding for the low-affinity nerve growth factor (NGF) receptor p75NGFR is transiently expressed during germ cell development. Gene expression for p75NGFR was detected in late-meiotic spermatocytes and early spermatids and was found to be co-expressed with trkB and trkC, two tyrosine kinase receptors, commonly regarded as the high-affinity receptors for brain-derived neurotrophic factor and neurotrophin-3. Gene transcripts for the high-affinity NGF receptor trkA were found exclusively in non-germ cells. Isolated Leydig cells, peritubular myoid cells and Sertoli cells, but not germ cells, could be identified as potential testicular NGF sources. Non-germ cells respond after incubation for several days with a sharp induction in NGF synthesis, which is accompanied by a loss of phenotypic expression patterns. The fact that p75NGFR mRNA expression was induced in cultured Sertoli cells and peritubular myoid cells suggests an autocrine mode of NGF action in these cells. Induction of NGF synthesis in cultured Leydig cells could be prevented by the glucocorticoid dexamethasone. Results indicate different roles for the individual neurotrophins in distinct testicular compartments and suggest that these neurotrophins might support testicular functions by signalling between individual cell types in an autocrine and paracrine manner.

scholarly journals F-actin bundles in Drosophila bristles are assembled from modules composed of short filaments.

1996 ◽  
Vol 135 (5) ◽  
pp. 1291-1308 ◽  
Author(s):  
L G Tilney ◽  
P Connelly ◽  
S Smith ◽  
G M Guild
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Modular Design ◽  
Thin Sections ◽  
Actin Bundle ◽  
Actin Bundles ◽  
Phalloidin Staining ◽  
Filament Bundles ◽  
End To End ◽  
As If

The actin bundles in Drosophila bristles run the length of the bristle cell and are accordingly 65 microns (microchaetes) or 400 microns (macrochaetes) in length, depending on the bristle type. Shortly after completion of bristle elongation in pupae, the actin bundles break down as the bristle surface becomes chitinized. The bundles break down in a bizarre way; it is as if each bundle is sawed transversely into pieces that average 3 microns in length. Disassembly of the actin filaments proceeds at the "sawed" surfaces. In all cases, the cuts in adjacent bundles appear in transverse register. From these images, we suspected that each actin bundle is made up of a series of shorter bundles or modules that are attached end-to-end. With fluorescent phalloidin staining and serial thin sections, we show that the modular design is present in nondegenerating bundles. Decoration of the actin filaments in adjacent bundles in the same bristle with subfragment 1 of myosin reveals that the actin filaments in every module have the same polarity. To study how modules form developmentally, we sectioned newly formed and elongating bristles. At the bristle tip are numerous tiny clusters of 6-10 filaments. These clusters become connected together more basally to form filament bundles that are poorly organized, initially, but with time become maximally cross-linked. Additional filaments are then added to the periphery of these organized bundle modules. All these observations make us aware of a new mechanism for the formation and elongation of actin filament bundles, one in which short bundles are assembled and attached end-to-end to other short bundles, as are the vertical girders between the floors of a skyscraper.

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