All Phenotypes Cby3<tm1b(EUCOMM)Hmgu> MGI Mouse

reproductive system phenotype ( J:344681 )

N	• adult males show no major changes in immunofluorescence staining of motile cilia in the efferent ducts

abnormal sperm flagellum morphology ( J:344681 )

• basigin (aka CD147) -- a transmembrane glycoprotein that is normally partitioned to the midpiece (MP) membrane of cauda epididymal sperm -- is distributed over the entire flagellar membrane, indicating a defective membrane diffusion barrier

abnormal sperm annulus morphology ( J:344681 )

• in cauda epididymal sperm immunostained for SEPTIN4 (septin 4, an annulus marker) and AKAP4 (A-kinase anchoring protein 4, a fibrous sheath marker), the annulus is present but misplaced caudally into the principle piece (PP) rather than positioned at the midpiece-principle piece (MP/PP) junction as in wild-type sperm; nearly all sperm have a mispositioned annulus into the PP

• SEM and TEM analyses show that the annulus is positioned ~2.5 um away from the MP/PP junction, with no major change found in midpiece length; moreover, the annulus is frequently deformed or occasionally missing

• periannular membranes appear to be deformed likely due to decreased membrane stiffness, allowing the annulus to migrate past the MP/PP junction into the principle piece

absent sperm annulus ( J:344681 )

• annulus is occasionally missing in cauda epididymal sperm

• however, testicular lysates show normal protein levels of annulus septins 2, 4, and 12

kinked sperm flagellum ( J:344681 )

• approximately 80% of cauda epididymal sperm exhibit sharply kinked sperm tails

oligozoospermia ( J:344681 )

• cauda epididymal sperm count is significantly lower than in wild-type males

asthenozoospermia ( J:344681 )

• sperm exhibit significantly decreased sperm velocity under both non-capacitating and capacitating conditions

decreased hyperactivated sperm motility ( J:344681 )

• sperm fail to become hyperactivated under capacitating conditions; phosphorylation of both protein kinase A (PKA) substrates and tyrosine-containing proteins is significantly reduced

decreased testis weight ( J:344681 )

• average adult testis weight is slightly lower than in wild-type males

• however, no overt histological abnormalities are detected on PAS-stained testis sections

abnormal spermiogenesis ( J:344681 )

• immunofluorescence staining of adult testis sections for CIBAR1 (CBY1 interacting BAR domain containing 1) and SEPTIN12 (septin 12) shows that, although CIBAR1 is recruited to the base of flagella prior to annulus migration, no CIBAR1 is detectable at the MP/PP junction in step 15 spermatids

• further analysis suggests that CIBAR1 fails to stably associate with the periannular membrane during annulus migration; the curved periannular membrane exhibits decreased rigidity, allowing the annulus to migrate over the fibrous sheath into the PP

male infertility ( J:344681 )

• adult males fail to produce offspring when mated with wild-type females for about 2 months