Analysis Tools
reproductive system
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• homozygotes exhibit no differences in testis and seminal vesicle weights and sperm counts relative to wild-type and heterozygous controls
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• mutant sperm with tails coiled around the heads are observed
• however, most cauda epididymal sperm appear relatively normal
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• homozygotes display a significantly higher frequency of epididymal sperm heads in which the nuclear apex is bent or blunted
• large rod-like chromatin condensation units are observed in nuclei of mutant step 13 spermatids, unlike the fine chromatin fibrils observed in wild type; after step 14, all of the chromatin becomes condensed and darkly stained with hematoxylin
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• EM revealed large rod-like chromatin condensation units in the nuclei of mutant step 13 spermatids, in contrast to the fine chromatin fibrils observed in wild type
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• only 23% of mutant sperm exhibit any motility
• most of these sperm fail to show forward progression
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• in steps 12 and 13, mutant spermatid nuclei exhibit increased levels of transition protein 2 (TNP2), accounting for 91% of the basic nuclear protein, as well as increased levels of protamine 2 precursor pP2 (2%-11% vs 0% in controls); in contrast, histone displacement occurs normally
• in steps 14-16 spermatids, pP2 is 21% of the total nuclear protein relative to only 10% and 5% in heterozygous and wild-type males, respectively, and the ratio of pP2 to pP2/11 is increased, suggesting abnormal P2 processing
• although most of the precursor is processed to mature P2, high levels of incompletely processed forms pesist in epididymal spermatozoa
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• Background Sensitivity: whereas fertile B6 x 129 F2 male homozygotes (16 weeks of age) exhibit normal litter sizes relative to wild-type controls, those on an inbred 129 background (9 weeks of age) display a 70% reduction in litter size relative to wild-type and heterozygous controls
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• Background Sensitivity: 70% of male homozygotes are infertile on a hybrid genetic background (B6 x 129 F2) versus 60% on an inbred 129 background
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• fertile homozygotes on both the B6 129 F2 and 129 backgrounds produce a reduced number of litters/pair relative to wild-type controls
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cellular
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• mutant sperm with tails coiled around the heads are observed
• however, most cauda epididymal sperm appear relatively normal
|
|
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• homozygotes display a significantly higher frequency of epididymal sperm heads in which the nuclear apex is bent or blunted
• large rod-like chromatin condensation units are observed in nuclei of mutant step 13 spermatids, unlike the fine chromatin fibrils observed in wild type; after step 14, all of the chromatin becomes condensed and darkly stained with hematoxylin
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• EM revealed large rod-like chromatin condensation units in the nuclei of mutant step 13 spermatids, in contrast to the fine chromatin fibrils observed in wild type
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• only 23% of mutant sperm exhibit any motility
• most of these sperm fail to show forward progression
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