Tag Archives: Translocation

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(7)

DISCUSSION(7)

No immunostaining was apparent until the onset of spermatid elongation, at which time the early flagellar structures showed patchy but distinct staining. In invertebrates, kinesin-II has been implicated in intraflagellar transport and, therefore, in the process of flagellar assembly and maintenance. In addition, KIF3 family members, of which kinesin-II is one, are thought to be involved with transport of a subset of membrane-bounded vesicles in neurons. Although KIF3 occurs at high levels in testis, the specific antibody (clone K2.4) used by us to probe rat testis did not detectably react with any structures within Sertoli cells. flovent inhaler

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(6)

The observation that IC74 co-sediments mainly with dynein heavy chain 1a (DHC1a) but not with DHC1b isoforms suggests that the dynein isotype that may be associated with spermatid translocation is the DHC1a form. buy birth control online

The most likely position of any dynein related to the junction plaques is on the cytoplasmic face of the endoplasmic reticulum component of the structures. The endoplasmic reticulum is the component of each plaque that is related to microtubules in vivo and is the component of the plague that binds microtubules in vitro. Moreover, there is much precedent for motor proteins being related to endoplasmic reticulum in general in cells. Localization of the motor at the ultrastructural level is needed to settle this issue and to determine other organelles with which the motor may be associated in Sertoli cells.

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(5)

DISCUSSION(5)

The finding that disassembly of the junction plaques with gelsolin increased the amount of dynein (IC74) detected in supernatants collected from epithelial fractions enriched for spermatid/junction complexes also supports the argument that the motor is located on the plaques; however, the data from these experiments are equivocal. Although less likely than the release of dynein from the actin-containing junction plaques, it is possible that IC74 in the su-pernatants from gelsolin-treated material was in some way released from contaminating manchettes in gelsolin-treated material. buy flovent inhaler

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(4)

Significantly, changes in the distribution of this immunoreactivity during spermatogenesis indicate further that an isoform of dynein may be recruited to these regions just before spermatid translocation. In fixed frozen sections of rat testis, the probe for IC74 accumulated in cytoplasmic areas adjacent to the crypts as spermatids moved deep into the crypts and was dramatically present in these regions just before movement of spermatids apically. buy yasmin online

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(3)

DISCUSSION(3)

In Sertoli cells, intense staining with the IC74 antibody was concentrated in columnar regions of the cell surrounding apical crypts containing attached spermatids. Although results from immunofluorescence and from experiments with gelsolin suggest an association of the immunoreactive protein with unique intercellular adhesion plaques related to spermatid heads, the staining pattern in fixed frozen sections of rat testis indicates that the protein is certainly not restricted to these areas. It occurs diffusely elsewhere in the cytoplasm and in linear tracts along structures, possibly cis-ternae of endoplasmic reticulum, projecting apically from regions containing the plaques. ventolin 100 mcg

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(2)

In addition, specific staining was observed in association with manchettes, microtubule-rich structures previously shown, using a different antibody, to contain an isoform of cytoplasmic dynein. Finally, staining in Sertoli cells occurred in regions known to be rich in microtubules and thought to be sites of active microtubule-based organelle (endoplasmic reticulum, mitochondria, vesicles) motility during spermatogenesis. proventil inhaler

Rat Testis Motor Proteins Associated with Spermatid Translocation: DISCUSSION(1)

DISCUSSION(1)

In the study reported here, we determined sites in the seminiferous epithelium that are immunoreactive with antibodies to the intermediate chain of cytoplasmic dynein and kinesin-II. Cheap Diskus Advair

Our results provide a morphological correlate for the high levels of cytoplasmic dynein detected previously in testis and in Sertoli cells. The data indicate that an isotype of cytoplasmic dynein may be present in Sertoli cell regions associated with apical crypts containing attached elongate spermatids. They also support the conclusion that a form of cytoplasmic dynein is most likely related to, but not entirely restricted to, unique intercellular attachment plaques that occur in these regions and that have been proposed to translocate spermatids in the seminiferous epithelium.

Rat Testis Motor Proteins Associated with Spermatid Translocation: RESULTS(5)

Controls for Kinesin-II Staining

Specific fluorescence was not observed when the primary antibody was replaced by normal mouse IgG, nor was it observed in other controls (Fig. 10). Buy Advair Diskus Online

IC74 Was Enriched in Supernatants From Gelsolin-Treated Spermatid/Junction Complexes

In each of the three experiments, actin filaments, present in controls, were virtually eliminated from plaques attached to spermatid/junction complexes incubated in gelsolin (Fig. 11). Significantly, the intermediate chain of cytoplasmic dy-nein (74 kDa) was obviously and consistently enriched, relative to controls, in supernatants collected from this material after removal of spermatids by slow-speed centrifugation (compare lanes 1 and 2 in each of the dynein immu-noblots in Fig. 11).

Rat Testis Motor Proteins Associated with Spermatid Translocation: RESULTS(4)

RESULTS(4)

Although the IC74 antibody has been shown previously to react with a 67-kDa isoform of the intermediate chain in blots of mammalian flagella, staining in sperm tails was inconsistently observed by us and was either weak or not detectable. ventolin 100 mcg

Controls for IC74 Staining

The pattern of fluorescence described above (Fig. 8A) was not present when the primary antibody was replaced by normal mouse IgG (Fig. 8B), nor was it present when the primary antibody was replaced by buffer alone (Fig. 8C). It was also absent in the control for autofluorescence (both the primary and the secondary antibodies replaced by buffer; Fig. 8D).

Rat Testis Motor Proteins Associated with Spermatid Translocation: RESULTS(3)

The signal associated with manchettes became less evident and eventually disappeared. The linear tracts of fluorescence in Sertoli cells were well established at stages when spermatids were at their deepest point in the epithelium (stage V, Fig. 5C). At stage VII (Fig. 5D), when spermatids had completed their translocation to the apex of the epithelium, intense fluorescence persisted in Sertoli cell cytoplasm surrounding spermatid heads and was also present more basally in columnar portions of the cells. After sperm release, this fluorescence pattern disappeared. proventil inhaler

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