Phenotypes for Cyp26b1 MGI:3764932 MGI Mouse

neonatal lethality, complete penetrance ( J:126705 )

• homozygous offspring were born at the expected mendelian ratio but died within hours of birth due most likely to respiratory distress

respiratory distress ( J:126705 )

abnormal limb morphology ( J:126705 )

• truncated limbs

abnormal craniofacial morphology ( J:126705 )

• severe craniofacial abnormalities

small testis ( J:126705 )

• testes of homozygous neonates were significantly smaller than wild-type

decreased male germ cell number ( J:126705 )

• virtually no germ cells were found in homozygous mice testes

• normal number of germ cells were found in ovaries of homozygous mutant neonates

abnormal male germ cell apoptosis ( J:126705 )

• at E12.5 mutant testes were indistinguishable from wild-type

• at E13.5, some germ cells exhibited dark condensed nuclei, typical of apoptotic cells

• at E14.5, some germ cells in mutant testes appeared to be apoptotic, whereas others appeared to be in the zygotene stage of meiosis

• at all stages examined mutant testes had significantly more TUNEL positive cells within the testis cords

• non-apoptotic germ cells in mutant testes contains cells in zygotene stage at E14.5 and in pachytene stage by E16.5 indicating that the germ cells enter meiosis

• immunohistochemical staining suggest that Sertoli and Leydig cells develop normally in mutant testes