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Phenotypes Associated with This Genotype
Genotype
MGI:2664240
Allelic
Composition
Mybl1tm1Epr/Mybl1tm1Epr
Genetic
Background
Not Specified
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Mybl1tm1Epr mutation (1 available); any Mybl1 mutation (33 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
reproductive system
• variable degeneration of most pachytene primary spermatocytes, ranging from early nuclear changes to advanced stages of cellular breakdown
• absence of post-meiotic spermatids and spermatozoa
• complete absence of spermatozoa (J:39632)
• however, serum testosterone levels were normal (J:39632)
• mice lack postmeiotic spermatids (J:175539)
• some spermatocytes fail to establish or maintain synapsis of homologous autosomes
• increased spermatocyte apoptosis, as shown by TUNEL staining
• impaired mammary gland epithelial expansion during pregnancy
• vacuolization of Sertoli cell cytoplasm
• slight reduction in size; however, number of tubules per testis was normal
• ~75% reduction in testis size, irrespective of age
• ~75% reduction in testis weight, irrespective of age
• germ cells enter meiotic prophase and arrest at pachytene (J:39632)
• before the mid-pachytene transition (J:175539)
(J:39632)
(J:175539)

growth/size/body
• size discrepancy became less pronounced with age
• mice eventually attained a nearly normal body size (approximately 90% for females and 70% for males)
• mice were indistinguishable from littermates at birth but lagged in growth during the first few weeks of life

endocrine/exocrine glands
• >60% reduction in proliferation of ductal cells and incomplete formation of alveolar structures at 2 days after pup delivery relative to lactating wild-type controls
• impaired mammary gland epithelial expansion during pregnancy
• abundant fat cells in mammary gland epithelium at 2 days after pup delivery versus rare fat cells in lactating wild-type controls
• vacuolization of Sertoli cell cytoplasm
• slight reduction in size; however, number of tubules per testis was normal
• ~75% reduction in testis size, irrespective of age
• ~75% reduction in testis weight, irrespective of age

behavior/neurological
• hunched posture of pups became less pronounced as mice matured (4 months of age)
• females were unable to nurse newborn offspring

integument
• >60% reduction in proliferation of ductal cells and incomplete formation of alveolar structures at 2 days after pup delivery relative to lactating wild-type controls
• impaired mammary gland epithelial expansion during pregnancy
• abundant fat cells in mammary gland epithelium at 2 days after pup delivery versus rare fat cells in lactating wild-type controls
• wrinkled appearance of pups became less pronounced as mice matured (4 months of age)

cellular
• variable degeneration of most pachytene primary spermatocytes, ranging from early nuclear changes to advanced stages of cellular breakdown
• absence of post-meiotic spermatids and spermatozoa
• complete absence of spermatozoa (J:39632)
• however, serum testosterone levels were normal (J:39632)
• mice lack postmeiotic spermatids (J:175539)
• germ cells enter meiotic prophase and arrest at pachytene (J:39632)
• before the mid-pachytene transition (J:175539)
• some spermatocytes fail to establish or maintain synapsis of homologous autosomes
• increased spermatocyte apoptosis, as shown by TUNEL staining


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
04/30/2024
MGI 6.23
The Jackson Laboratory