All Phenotypes Prm2<em1Hsc> MGI Mouse

reproductive system phenotype ( J:243626 , J:295027 )

N	• female mice are fertile and produce a normal average litter size when mated with heterozygous males (J:243626) • male mice show normal testis weight, epididymal sperm count and testis morphology, indicating normal spermatogenesis (J:243626)
N	• in vitro, testicular sperm initiate normal development of blastocyst stage embryos upon intracytoplasmic sperm injection (ICSI) into wild-type oocytes (J:295027)

abnormal sperm midpiece morphology ( J:243626 )

• in most epididymal sperm, the midpiece of the flagellum is wrapped around the sperm head

necrospermia ( J:295027 )

• eosin-nigrosin staining showed that the vast majority of epididymal sperm stain pink, indicating reduced membrane integrity

• a hypo-osmotic test (where tail swelling and/or curling = live sperm) showed an abnormally low % of hypo-osmotic reactive epididymal sperm (~30%), indicating reduced sperm viability

abnormal sperm head morphology ( J:243626 , J:295027 )

• most epididymal sperm show an abnormally shaped head with an undulating plasma membrane; the midpiece of the flagellum is wrapped around the sperm head (J:243626)

• most cauda epididymal sperm show decreased sperm head length and width and loss of the sickle-shape that is typical of control sperm (J:295027)

• loss of the characteristic sperm hook leads to an increase in circularity and ellipticity (J:295027)

detached acrosome ( J:243626 )

• most epididymal sperm show detachment of the acrosome at the acrosome-nuclear interface

abnormal sperm nucleus morphology ( J:243626 , J:295027 )

• most epididymal sperm exhibit nuclear matrix alterations, indicating loss of chromatin integrity (J:243626)

• 80% of epididymal sperm show intermediate to low chromatin density whereas 80% of wild-type sperm show high chromatin integrity (J:243626)

• agarose gel electrophoresis of sperm genomic DNA showed that most of sperm DNA is degraded into fragments of ~250 bp in size, suggesting DNA damage (J:243626)

• in a sperm chromatin structure assay (SCSA), >80% of acid-treated sperm cells show intense red fluorescence indicating strong intercalation of acridine orange into damaged single-stranded DNA and thus strong DNA damage (J:243626)

• cauda epididymal sperm show severe changes in sperm nuclear morphology whereas step 16 testicular spermatids do not (J:295027)

small sperm head ( J:295027 )

• epididymal sperm show a >40% reduction in sperm head size; a decline in sperm length and width results in decreased sperm area and perimeter

abnormal spermatid morphology ( J:243626 )

• testicular spermatids show abnormal nuclear matrix morphology with a fine-grained, sometimes coarse-grained texture

• abnormal chromatin condensation is first seen in step 12 elongating spermatids and becomes more obvious in step 16 elongated spermatids prior to sperm release when heterogeneous chromatin packaging and vesiculation are observed

• however, sperm head elongation and formation of the acrosome and manchette are normal in testicular spermatids

abnormal spermiogenesis ( J:243626 )

male infertility ( J:243626 , J:295027 )

• male mice fail to sire offspring (J:243626)

• in vitro, male infertility can be overcome by ICSI of testicular sperm (J:295027)

abnormal sperm physiology ( J:243626 , J:295027 )

• loading sperm populations with Cal520-AM (an Ca²⁺ dye) followed by stimulation with K8.6, 8-Br-cAMP, NH4Cl, or with the Ca²⁺-ionophore ionomycin fails to evoke a Ca²⁺ influx in sperm, unlike in similarly treated wild-type and heterozygous sperm (J:243626)

• fluorescence microscopy showed that sperm loaded with Cal520-AM show no fluorescence in the midpiece, unlike similarly loaded heterozygous sperm, suggesting that severe plasma membrane defects may prevent dye loading (J:243626)

• epididymal, but not testicular, sperm exhibit loss of antioxidant capacity as shown by downregulation of ROS scavenger proteins (SOD1 and PRDX5), and an increased level of 8-OHdG (a biomarker for oxidative DNA damage) during epididymal transit (J:295027)

immotile sperm ( J:243626 )

• all epididymal sperm show complete loss of motility due severe membrane defects

• sperm tethered with their heads to a glass surface fail to show the symmetrical flagellar waveform observed in wild-type and heterozygous sperm