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Sertoli cell microtubules: their polarity and binding to spermatid associated ectoplasmic specializations Redenbach, Darlene Marie
Abstract
During spermatogenesis, spermatogenic cells are moved through the blood testis barrier from the basal to the apical compartment, where they become oriented parallel to the long axis of the Sertoli cell, and situated within Sertoli cell crypts. They are moved again toward the base of the epithelium, before being translocated across the epithelium for release into the tubule lumen. Crypts are lined with unique actin containing submembrane structures called ectoplasmic specializations (ESs) that form part of the Sertoli cell-spermatid junction. ESs consist of the Sertoli cell membrane, a fenestrated cistern of smooth endoplasmic reticulum, and a highly ordered intervening array of actin filaments. ESs are thought to participate in establishing junctional domains at Sertoli cell-spermatid adhesion junctions, which serve to anchor the developing spermatids within the Sertoli cell crypts. Sertoli cell microtubules occur adjacent to the endoplasmic reticulum of the ES (ESER), oriented parallel to the long axis of the cell, and to the direction of spermatid translocation. Other investigators have described linkages between the ESER and adjacent microtubules. Sertoli cell microtubules have been suggested to aid in orientation and positioning of spermatogenic cells, within the seminiferous epithelium. It is proposed that this may be achieved by a microtubule-based transport mechanism known to be involved in establishing and maintaining organelle positioning in other cells. As part of a study to test the hypothesis that spermatid translocation is a microtubule-based event, the polarity of Sertoli cell microtubules was determined. The potential for binding between spermatid-ESs and microtubules was assayed, and the binding characterized, using a selection of conditions known to alter organelle-microtubule interaction in other systems. The results of this study indicate that Sertoli cell microtubules are orientated with their minus-end directed toward the apical surface of the cell and that microtubules bind to spermatid-ES complexes, are releasable in the presence of nucleotides, and share binding properties with known mechanoenzymes. These results are consistent with the hypothesis that spermatids are moved through the seminiferous epithelium by a microtubule-based transport mechanism.
Item Metadata
Title |
Sertoli cell microtubules: their polarity and binding to spermatid associated ectoplasmic specializations
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1992
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Description |
During spermatogenesis, spermatogenic cells are moved through the blood testis
barrier from the basal to the apical compartment, where they become oriented parallel
to the long axis of the Sertoli cell, and situated within Sertoli cell crypts. They are
moved again toward the base of the epithelium, before being translocated across the
epithelium for release into the tubule lumen. Crypts are lined with unique actin
containing submembrane structures called ectoplasmic specializations (ESs) that form
part of the Sertoli cell-spermatid junction. ESs consist of the Sertoli cell membrane, a
fenestrated cistern of smooth endoplasmic reticulum, and a highly ordered intervening
array of actin filaments. ESs are thought to participate in establishing junctional
domains at Sertoli cell-spermatid adhesion junctions, which serve to anchor the
developing spermatids within the Sertoli cell crypts. Sertoli cell microtubules occur
adjacent to the endoplasmic reticulum of the ES (ESER), oriented parallel to the long
axis of the cell, and to the direction of spermatid translocation. Other investigators have
described linkages between the ESER and adjacent microtubules. Sertoli cell
microtubules have been suggested to aid in orientation and positioning of spermatogenic
cells, within the seminiferous epithelium. It is proposed that this may be achieved by a
microtubule-based transport mechanism known to be involved in establishing and
maintaining organelle positioning in other cells. As part of a study to test the hypothesis
that spermatid translocation is a microtubule-based event, the polarity of Sertoli cell
microtubules was determined. The potential for binding between spermatid-ESs and
microtubules was assayed, and the binding characterized, using a selection of conditions
known to alter organelle-microtubule interaction in other systems. The results of this
study indicate that Sertoli cell microtubules are orientated with their minus-end
directed toward the apical surface of the cell and that microtubules bind to spermatid-ES
complexes, are releasable in the presence of nucleotides, and share binding properties
with known mechanoenzymes. These results are consistent with the hypothesis that
spermatids are moved through the seminiferous epithelium by a microtubule-based
transport mechanism.
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Extent |
8610882 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-01-05
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0086715
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1992-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.