Analysis Tools
reproductive system
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• homozygotes display normal testis weights, sperm counts and sperm flagellum length, with no signs of increased cell death or altered epithelial cell composition in stage X spermatogenic tubules
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• >50% of sperm cells exhibit severely abnormal head shapes while remaining spermatozoa show various mild malformations, such as blunt sperm tips, abnormal formation of the nuclear base, and abnormal attachment of the tail
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• homozygotes show a much higher frequency of severe sperm head malformations relative to wild-type and heterozygous controls
• most severely abnormal sperm heads assume a hammer- or cupcake-like shape
• mild defects include absence of an indentation at the tail attachment site
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• mild defects include blunt nuclear tips and concave indentations at the base of the sperm nucleus
• >50% of sperm exhibit severely malformed nuclei
• spermatids undergoing elongation and condensation show a lack of coherence between the inner and outer nuclear membranes and fail to generate a continuous nuclear dense lamina in the subacrosomal region
• other defects include abnormal invaginations of the nuclear envelope into the nuclear lumen, separation and bulging of the outer or inner membrane of the nuclear envelope, and detachment of the chromatin from the inner nuclear membrane
• the nuclear lamina appears stretched and appears to form abnormal gaps esp. in regions that are most likely exposed to increased physical forces during nuclear shaping
• abnormal nuclear envelope stretching and chromatin detachment is also noted in round spermatids at earlier steps, prior to the formation of manchette and acroplaxome
• despite abnormal spermatid nuclear shaping, chromatin condensation is mostly normal even in severely malformed nuclei, and the basic shaping structures (manchette, F-actin rings, flat developing acrosome and acroplaxome) are normally formed
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• spermatids undergoing elongation and condensation exhibit structural defects in the nuclear envelope and chromatin detachment associated with abnormal nuclear shaping
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• male homozygotes show nuclear envelope defects during the nuclear reshaping process of spermatid elongation and condensation
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• 5 of 9 male homozygotes are infertile due to a primary fertilization defect of sperm
• however, female fertility, mating behavior, and frequency of copulation plugs are normal
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• 4 of 9 male homozygotes sire infrequent and small litters
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• following natural mating of male homozygotes with superovulated wild-type females, only 5% of all embryos/oocytes retrieved at 1.5 dpc have progressed to the 2-cell stage versus 70% retrieved after mating of wild-type males with wild-type females
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cellular
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• >50% of sperm cells exhibit severely abnormal head shapes while remaining spermatozoa show various mild malformations, such as blunt sperm tips, abnormal formation of the nuclear base, and abnormal attachment of the tail
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• homozygotes show a much higher frequency of severe sperm head malformations relative to wild-type and heterozygous controls
• most severely abnormal sperm heads assume a hammer- or cupcake-like shape
• mild defects include absence of an indentation at the tail attachment site
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|
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• >50% of sperm exhibit severely malformed nuclei
• mild defects include blunt nuclear tips and concave indentations at the base of the sperm nucleus
• spermatids undergoing elongation and condensation show a lack of coherence between the inner and outer nuclear membranes and fail to generate a continuous nuclear dense lamina in the subacrosomal region
• other defects include abnormal invaginations of the nuclear envelope into the nuclear lumen, separation and bulging of the outer or inner membrane of the nuclear envelope, and detachment of the chromatin from the inner nuclear membrane
• the nuclear lamina appears stretched and appears to form abnormal gaps esp. in regions that are most likely exposed to increased physical forces during nuclear shaping
• abnormal nuclear envelope stretching and chromatin detachment is also noted in round spermatids at earlier steps, prior to the formation of manchette and acroplaxome
• despite abnormal spermatid nuclear shaping, chromatin condensation is mostly normal even in severely malformed nuclei, and the basic shaping structures (manchette, F-actin rings, flat developing acrosome and acroplaxome) are normally formed
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• spermatids undergoing elongation and condensation exhibit structural defects in the nuclear envelope and chromatin detachment associated with abnormal nuclear shaping
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