Analysis Tools
reproductive system
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• ~60% reduction in total epididymal spermatozoa counts per mouse relative to wild-type and heterozygous littermates
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• marked reduction in the number of PLZF-positive spermatogonial stem cells per tubule in adult testes relative to wild-type controls
• 2.5-fold decrease in the number of PLZF-positive spermatogonia in P5 neonatal testes relative to wild-type controls
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• significant decrease in primordial germ cell (PGC) number at E14.5 with severe loss of PGCs in early postnatal testis sections (P1 and P5), as shown by TRA98 staining
• decreased PGC number is associated with only mild increases in TUNEL-positive cells at these stages
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• mild increase in PGC apoptosis at E17.5 and P1 relative to wild-type controls
• at E14.5, very few PGCs are detected; however, TUNEL labeling is non-significantly increased, suggesting proliferative defects in PGC population, either during migration or in the fetal testis
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• reduced PGC proliferation in fetal testis relative to wild-type controls
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• impaired spermatogonial proliferation associated with mildly increased apoptosis during fetal testis development
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• only a few primary or no developing follicles are present
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• at 35 weeks of age, 23% of female gonads show ovarian dysgenesis relative to 5.6% in wild-type controls
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ovary cyst
(
J:227115
)
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• females are particularly prone to epithelial cystic ovaries (4 tumors out of 23 females)
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• although many tubules appear to be populated with the full complement of spermatogonia, 34% of seminiferous tubules appear atrophic relative to 11% in wild-type controls
• atrophy ranges from mild to severe, with some tubules devoid of all spermatogenic layers
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• reduced seminiferous epithelial cellularity in adult males
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• significantly increased Sertoli cell number per tubule in adult testes as well as in P5 neonatal testes relative to wild-type controls
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(J:227115)
• mutant testes are much smaller than wild-type
(J:227337)
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• decreased testis/body weight ratio that is not significantly altered by age
(J:227115)
• at 12-14 weeks of age, testis weight is reduced by ~30% relative to wild-type controls
(J:227337)
• however, overall testis histology is normal, with no significant differences in apoptosis as shown by TUNEL staining
(J:227337)
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• reduced testis cellularity in adult males
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• endometrial glandular hyperplasia (3 tumors out of 23 females)
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• Giemsa-stained diakinesis spreads revealed an increase in chiasmata numbers in spermatocyte nuclei, in line with the elevation in MLH1 foci
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• analysis of spermatocyte spreads revealed largely normal chromosome synapsis and prophase I progression in adult males; however, 1-5 % of cells display aberrant synapsis events
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• over a 5-month period, homozygous matings produced only 10 litters and 66 pups (0.3 litter per 21-d gestation interval and 2.2 pups per litter), whereas heterozygous matings yielded 31 litters with 166 pups (0.9 litter per 21-d gestation interval and 4.7 pups per litter)
• subfertility is likely due to germ cell attrition during development
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• over a 5-month period, homozygous matings produced only 2.2 pups per litter versus 4.7 pups per litter obtained by heterozygous matings
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growth/size/body
ovary cyst
(
J:227115
)
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• females are particularly prone to epithelial cystic ovaries (4 tumors out of 23 females)
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cellular
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• ~60% reduction in total epididymal spermatozoa counts per mouse relative to wild-type and heterozygous littermates
|
|
|
• marked reduction in the number of PLZF-positive spermatogonial stem cells per tubule in adult testes relative to wild-type controls
• 2.5-fold decrease in the number of PLZF-positive spermatogonia in P5 neonatal testes relative to wild-type controls
|
|
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• significant decrease in primordial germ cell (PGC) number at E14.5 with severe loss of PGCs in early postnatal testis sections (P1 and P5), as shown by TRA98 staining
• decreased PGC number is associated with only mild increases in TUNEL-positive cells at these stages
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• increased frequency of metaphases with radial chromosomes in MEFs treated with mitomycin C
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• MEFs exhibit spontaneous DNA damage (gammaH2AX foci) even in the absence of DNA-damaging agents
(J:227115)
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• MEFs display exquisite sensitivity to the interstrand cross-link (ICL)-inducing agent mitomycin C, but not camptothecin or UV, and accumulate radial chromosomes, a hallmark of Fanconi anemia
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• mild increase in PGC apoptosis at E17.5 and P1 relative to wild-type controls
• at E14.5, very few PGCs are detected; however, TUNEL labeling is non-significantly increased, suggesting proliferative defects in PGC population, either during migration or in the fetal testis
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• reduced PGC proliferation in fetal testis relative to wild-type controls
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• impaired spermatogonial proliferation associated with mildly increased apoptosis during fetal testis development
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• in culture, the proliferative capacity of targeted embryonic stem (ES) cells is reduced by ~50% relative to wild-type E14 parental ES cells
• however, no changes in apoptosis, ES cell morphology or gross characteristics are observed
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• primary MEFs undergo spontaneous senescence at later passages, unlike wild-type MEFs
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• in response to mitomycin C treatment, MEFs accumulate increased levels of DSB intermediates with accelerated kinetics relative to wild-type controls
(J:227115)
• FANCD2 and RAD51 foci persist much longer than in wild-type MEFs
(J:227115)
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• although early events of DSB induction/repair appear mostly normal and BRCA1 assembles normally on meiotic chromosome cores during prophase I, a small subset of spermatocytes (<1% per mouse) show delayed removal of the phosphorylated form of histone H2AX (gammaH2AX) along the autosomes in line with cases of aberrant synapsis
(J:227337)
• spermatocytes showing aberrant synapsis events and delayed DSB repair tend to reside in small clumps of 3-8 cells, suggesting close vicinity within their seminiferous tubular origins and/or shared clonal spermatogonial origins
(J:227337)
• MutL homolog-1 (MLH1) focus frequency is significantly increased in pachytene spermatocytes, indicating increased DSB repair via class I crossover (CO) events
(J:227337)
• increase in CO events is associated with increased/persistent localization of the BLM helicase protein through late prophase I
(J:227337)
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• significantly slower replication fork extension rates in unchallenged mutant MEFs cells relative to wild-type controls; further exacerbated by aphidicolin treatment
• increased levels of asymmetric replication forks in mutant MEFs relative to wild-type controls under both unchallenged and aphidicolin-treated conditions
• significantly shorter interorigin distances in mutant MEFs relative to wild-type controls under both unchallenged and aphidicolin-treated conditions
• surprisingly, mutant MEFs are insensitive to G4-stabilizing drugs and do not present with telomere fragility
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• primary MEF lines derived from timed matings of heterozygotes display high levels of spontaneous microsatellite instability (MSI) corresponding to both expansions and contractions of repeat sequences
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• MEFs exhibit hypersensitivity to low doses of the replication inhibitor aphidicolin
• in addition, the levels of gammaH2AX foci are significantly increased in MEFs after aphidicolin treatment
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endocrine/exocrine glands
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• only a few primary or no developing follicles are present
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• at 35 weeks of age, 23% of female gonads show ovarian dysgenesis relative to 5.6% in wild-type controls
|
ovary cyst
(
J:227115
)
|
|
• females are particularly prone to epithelial cystic ovaries (4 tumors out of 23 females)
|
|
|
• although many tubules appear to be populated with the full complement of spermatogonia, 34% of seminiferous tubules appear atrophic relative to 11% in wild-type controls
• atrophy ranges from mild to severe, with some tubules devoid of all spermatogenic layers
|
|
|
• reduced seminiferous epithelial cellularity in adult males
|
|
|
• significantly increased Sertoli cell number per tubule in adult testes as well as in P5 neonatal testes relative to wild-type controls
|
|
|
(J:227115)
• mutant testes are much smaller than wild-type
(J:227337)
|
|
|
• decreased testis/body weight ratio that is not significantly altered by age
(J:227115)
• at 12-14 weeks of age, testis weight is reduced by ~30% relative to wild-type controls
(J:227337)
• however, overall testis histology is normal, with no significant differences in apoptosis as shown by TUNEL staining
(J:227337)
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• reduced testis cellularity in adult males
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• Harderian gland adenomas are the most prominent epithelial tumors in males (5 tumors out of 21 males)
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• pituitary gland adenomas (3 tumors out of 23 females)
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homeostasis/metabolism
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• in response to mitomycin C treatment, MEFs accumulate increased levels of DSB intermediates with accelerated kinetics relative to wild-type controls
(J:227115)
• FANCD2 and RAD51 foci persist much longer than in wild-type MEFs
(J:227115)
|
|
|
|
• although early events of DSB induction/repair appear mostly normal and BRCA1 assembles normally on meiotic chromosome cores during prophase I, a small subset of spermatocytes (<1% per mouse) show delayed removal of the phosphorylated form of histone H2AX (gammaH2AX) along the autosomes in line with cases of aberrant synapsis
(J:227337)
• spermatocytes showing aberrant synapsis events and delayed DSB repair tend to reside in small clumps of 3-8 cells, suggesting close vicinity within their seminiferous tubular origins and/or shared clonal spermatogonial origins
(J:227337)
• MutL homolog-1 (MLH1) focus frequency is significantly increased in pachytene spermatocytes, indicating increased DSB repair via class I crossover (CO) events
(J:227337)
• increase in CO events is associated with increased/persistent localization of the BLM helicase protein through late prophase I
(J:227337)
|
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• significantly slower replication fork extension rates in unchallenged mutant MEFs cells relative to wild-type controls; further exacerbated by aphidicolin treatment
• increased levels of asymmetric replication forks in mutant MEFs relative to wild-type controls under both unchallenged and aphidicolin-treated conditions
• significantly shorter interorigin distances in mutant MEFs relative to wild-type controls under both unchallenged and aphidicolin-treated conditions
• surprisingly, mutant MEFs are insensitive to G4-stabilizing drugs and do not present with telomere fragility
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neoplasm
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• tumor-free survival is significantly reduced in aged mice relative to wild-type controls
• 50% of mice presented with tumors by 559 days
• 74% of aged mice developed tumors, with a greater incidence in females than in males (~74% vs ~48%)
• 60% of aged mice presented with more than one primary tumor
• 49% of mice developed tumors of epithelial origin
• females presented with more epithelial tumors than males, corresponding to a frequency of ~52% in females and 39% in males
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• Harderian gland adenomas are the most prominent epithelial tumors in males (5 tumors out of 21 males)
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• pituitary gland adenomas (3 tumors out of 23 females)
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• 26% of mice developed lymphomas relative to ~10% in wild-type controls
• lymphoma-free median survival age is significantly decreased relative to wild-type controls
• females are more susceptible to lymphomas, with an incidence of ~40% relative to 9.5% in males
• lymphomas were widely spread in most mice, with an increased frequency in the spleen, B cells, and mesenteric and salivary lymph nodes
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nervous system
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• pituitary gland adenomas (3 tumors out of 23 females)
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liver/biliary system
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• increased frequency of liver steatosis in aged mice
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