Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes
Summary Tubulobulbar complexes are actin-related endocytic structures that form at sites of intercellular attachment in the seminiferous epithelium and are proposed to internalize intact junctions. In this study, we test the prediction that altering the structure/function of tubulobulbar complexes r...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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The Company of Biologists
2012-08-01
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| Series: | Biology Open |
| Subjects: | |
| Online Access: | http://bio.biologists.org/content/1/11/1069 |
| _version_ | 1818667742788583424 |
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| author | J'Nelle S. Young Marc De Asis Julian Guttman A. Wayne Vogl |
| author_facet | J'Nelle S. Young Marc De Asis Julian Guttman A. Wayne Vogl |
| author_sort | J'Nelle S. Young |
| collection | DOAJ |
| description | Summary
Tubulobulbar complexes are actin-related endocytic structures that form at sites of intercellular attachment in the seminiferous epithelium and are proposed to internalize intact junctions. In this study, we test the prediction that altering the structure/function of tubulobulbar complexes results in failure to release mature spermatids from Sertoli cells. We used an in vivo knockdown strategy to target cortactin, a component of tubulobulbar complexes, in Sprague Dawley rats. In each animal, one testis was surgically injected with cortactin siRNA reagents and the other testis was injected with non-targeting siRNA. After three days, experimental and control testes were processed for immunoblotting, electron microscopy or immunofluorescence microscopy. In testis sections immunostained for cortactin or labeled for filamentous actin, fluorescence microscopy revealed that tubulobulbar complexes were shorter in siRNA-treated testes relative to controls. Significantly, in the knockdown testes, spermiation was delayed in some tubules and had failed in others. When evaluated by electron microscopy, adhesion complexes (ectoplasmic specializations) remained associated with mature spermatids that failed to be released from Sertoli cells. Immunoblots both of whole testis lysates and of isolated seminiferous epithelial lysates confirmed that cortactin expression was knocked-down in experimental testes and in the seminiferous epithelium respectively, relative to controls. Moreover, in testes injected with siRNA reagents with a dye modification on one of the four targeting siRNA sequences, dye clusters were detected at the base of the epithelium confirming that the reagents entered Sertoli cells. Our results are consistent with the hypothesis that tubulobulbar complexes internalize intercellular junctions and that they are a significant component of the sperm release mechanism. |
| first_indexed | 2024-12-17T06:25:16Z |
| format | Article |
| id | doaj.art-a36d2837b522492d987195b2ca00cd63 |
| institution | Directory Open Access Journal |
| issn | 2046-6390 |
| language | English |
| last_indexed | 2024-12-17T06:25:16Z |
| publishDate | 2012-08-01 |
| publisher | The Company of Biologists |
| record_format | Article |
| series | Biology Open |
| spelling | doaj.art-a36d2837b522492d987195b2ca00cd632022-12-21T22:00:18ZengThe Company of BiologistsBiology Open2046-63902012-08-011111069107710.1242/bio.2012251920122519Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testesJ'Nelle S. Young0Marc De Asis1Julian Guttman2A. Wayne Vogl3 Department of Cellular and Physiological Sciences, Faculty of Medicine, Life Sciences Centre, 2350 Health Sciences Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada Department of Cellular and Physiological Sciences, Faculty of Medicine, Life Sciences Centre, 2350 Health Sciences Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada Department of Biological Sciences, Simon Fraser University, Shrum Science Centre, Room B8276, 8888 University Drive, Burnaby, BC V5A 1S6, Canada Department of Cellular and Physiological Sciences, Faculty of Medicine, Life Sciences Centre, 2350 Health Sciences Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada Summary Tubulobulbar complexes are actin-related endocytic structures that form at sites of intercellular attachment in the seminiferous epithelium and are proposed to internalize intact junctions. In this study, we test the prediction that altering the structure/function of tubulobulbar complexes results in failure to release mature spermatids from Sertoli cells. We used an in vivo knockdown strategy to target cortactin, a component of tubulobulbar complexes, in Sprague Dawley rats. In each animal, one testis was surgically injected with cortactin siRNA reagents and the other testis was injected with non-targeting siRNA. After three days, experimental and control testes were processed for immunoblotting, electron microscopy or immunofluorescence microscopy. In testis sections immunostained for cortactin or labeled for filamentous actin, fluorescence microscopy revealed that tubulobulbar complexes were shorter in siRNA-treated testes relative to controls. Significantly, in the knockdown testes, spermiation was delayed in some tubules and had failed in others. When evaluated by electron microscopy, adhesion complexes (ectoplasmic specializations) remained associated with mature spermatids that failed to be released from Sertoli cells. Immunoblots both of whole testis lysates and of isolated seminiferous epithelial lysates confirmed that cortactin expression was knocked-down in experimental testes and in the seminiferous epithelium respectively, relative to controls. Moreover, in testes injected with siRNA reagents with a dye modification on one of the four targeting siRNA sequences, dye clusters were detected at the base of the epithelium confirming that the reagents entered Sertoli cells. Our results are consistent with the hypothesis that tubulobulbar complexes internalize intercellular junctions and that they are a significant component of the sperm release mechanism.http://bio.biologists.org/content/1/11/1069Tubulobulbar complexesCortactinSpermatogenesisTestisSpermiationActin |
| spellingShingle | J'Nelle S. Young Marc De Asis Julian Guttman A. Wayne Vogl Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes Biology Open Tubulobulbar complexes Cortactin Spermatogenesis Testis Spermiation Actin |
| title | Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes |
| title_full | Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes |
| title_fullStr | Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes |
| title_full_unstemmed | Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes |
| title_short | Cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes |
| title_sort | cortactin depletion results in short tubulobulbar complexes and spermiation failure in rat testes |
| topic | Tubulobulbar complexes Cortactin Spermatogenesis Testis Spermiation Actin |
| url | http://bio.biologists.org/content/1/11/1069 |
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