Analysis Tools
reproductive system
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• female mice are fertile and give birth to normal litter sizes
• despite male infertility, testis weights are normal at 6 weeks of age
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• epididymal sperm concentrations are significantly lower than those in wild-type controls
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• sperm exhibit abnormal head or tail morphology
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• ~70-80% of sperm exhibit abnormal tail morphology including bent, coiled, crinkled, and shortened flagella
• however, TEM analysis showed no major alterations in the basal body, axoneme, mitochondria, outer dense fibers or fibrous sheath in newly formed spermatozoa
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• all mature spermatozoa exhibit abnormal head morphologies including macrocephaly, microcephaly, and irregular shapes
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• male germ cells show defects in the filamentous actin (F-actin)-scaffolded acroplaxome during spermatid elongation
• in elongating (steps 9-12) spermatids, acrosomes become uncoupled from the underlying F-actin- and keratin 5-scaffolded acroplaxome, as evident by widening of the groove belt
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• SEM analysis showed a disorganized anterior acrosome and absence of a distinct equatorial segment, post-acrosomal sheath, ventral spur, and sharp hook rim
• TEM imaging showed that some step 8 spermatids contain highly amorphous, fragmented acrosomal vesicles and/or detached acrosomal granules
• in step 9-10 spermatids, the posterior edge of the acrosome is no longer juxtaposed to the perinuclear ring of the manchette, thus widening the groove belt and deforming the underlying nuclear lamina
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• in some step 9-10 spermatids, widening of the groove belt is associated with a detached acrosome
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• in some sperm with demembranated head structures, mis-localized axonemal components are found to be wrapped around the nucleus
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• PAS staining of adult testes showed malformed elongating spermatids that fail to extend properly by step 12 of spermatogenesis
• TEM imaging showed that some step 8 spermatids contain highly amorphous, fragmented acrosomal vesicles and/or detached acrosomal granules
• elongating (steps 9-12) spermatids exhibit abnormal anterior head structures associated with dysregulation of the acrosome-acroplaxome complex
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• TUNEL staining showed that >10% of epididymal sperm exhibit DNA fragmentation whereas only 1.5% of wild-type or heterozygous sperm are TUNEL-positive
• however, no increased TUNEL staining is observed in the testes
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• CASA analysis revealed a severe reduction in progressive sperm motility
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• percentage of epididymal sperm that are motile is significantly lower than that in wild-type controls
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• male germ cells exhibit head defects that become increasingly overt during spermiogenesis
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• crosses between 7-week-old males and age-matched wild-type females of known fertility fail to produce viable pups
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• isolated epididymal sperm fail to fertilize wild-type oocytes under standard in vitro fertilization (IVF) conditions
• in vitro, sperm retain their ability to undergo capacitation and the acrosome reaction but show reduced oocyte binding and penetration of cumulus-oocyte complexes (COCs)
• however, intracytoplasmic sperm injection (ICSI) of mutant sperm yields embryos that can undergo uterine implantation to produce viable pups
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cellular
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• epididymal sperm concentrations are significantly lower than those in wild-type controls
|
|
|
• sperm exhibit abnormal head or tail morphology
|
|
|
• ~70-80% of sperm exhibit abnormal tail morphology including bent, coiled, crinkled, and shortened flagella
• however, TEM analysis showed no major alterations in the basal body, axoneme, mitochondria, outer dense fibers or fibrous sheath in newly formed spermatozoa
|
|
|
• all mature spermatozoa exhibit abnormal head morphologies including macrocephaly, microcephaly, and irregular shapes
|
|
|
• male germ cells show defects in the filamentous actin (F-actin)-scaffolded acroplaxome during spermatid elongation
• in elongating (steps 9-12) spermatids, acrosomes become uncoupled from the underlying F-actin- and keratin 5-scaffolded acroplaxome, as evident by widening of the groove belt
|
|
|
• SEM analysis showed a disorganized anterior acrosome and absence of a distinct equatorial segment, post-acrosomal sheath, ventral spur, and sharp hook rim
• TEM imaging showed that some step 8 spermatids contain highly amorphous, fragmented acrosomal vesicles and/or detached acrosomal granules
• in step 9-10 spermatids, the posterior edge of the acrosome is no longer juxtaposed to the perinuclear ring of the manchette, thus widening the groove belt and deforming the underlying nuclear lamina
|
|
|
• in some step 9-10 spermatids, widening of the groove belt is associated with a detached acrosome
|
|
|
• in some sperm with demembranated head structures, mis-localized axonemal components are found to be wrapped around the nucleus
|
|
|
• PAS staining of adult testes showed malformed elongating spermatids that fail to extend properly by step 12 of spermatogenesis
• TEM imaging showed that some step 8 spermatids contain highly amorphous, fragmented acrosomal vesicles and/or detached acrosomal granules
• elongating (steps 9-12) spermatids exhibit abnormal anterior head structures associated with dysregulation of the acrosome-acroplaxome complex
|
|
|
• TUNEL staining showed that >10% of epididymal sperm exhibit DNA fragmentation whereas only 1.5% of wild-type or heterozygous sperm are TUNEL-positive
• however, no increased TUNEL staining is observed in the testes
|
|
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• CASA analysis revealed a severe reduction in progressive sperm motility
|
|
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• percentage of epididymal sperm that are motile is significantly lower than that in wild-type controls
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