All Phenotypes Sypl1<tm1b(KOMP)Wtsi> MGI Mouse

reproductive system phenotype ( J:339267 )

N	• male mice show no significant alterations in (body and) testis weights, testicular germ cell populations or cauda epididymal sperm count relative to heterozygous control littermates

teratozoospermia ( J:339267 )

• sperm show a defect in cytoplasmic droplet (CD) formation; the CD region is greatly reduced in size and devoid of saccular elements in step16 spermatids and epididymal sperm

• however, the sperm mitochondrial sheath, acrosomes, nuclei and flagellar components are normal

abnormal sperm connecting piece morphology ( J:339267 )

• most cauda epididymal sperm exhibit a bent head at the neck region

abnormal sperm midpiece morphology ( J:339267 )

• cauda epididymal sperm show a bent midpiece phenotype

• % of bent midpiece sperm is significantly higher than that of controls in testes, caput and cauda epididymides

kinked sperm flagellum ( J:339267 )

• cauda epididymal sperm show abnormal flagellar angulation, mainly in a bent head at the neck region or bent midpiece phenotype

• % of angulated sperm is significantly higher than that of controls in testes, caput and cauda epididymides

• no flagellar angulation is observed in unreleased step 16 spermatids

abnormal sperm head morphology ( J:339267 )

• most cauda epididymal sperm exhibit a bent head at the neck region

• % of bent head sperm is significantly higher than that of controls in testes, caput and cauda epididymides

decreased sperm progressive motility ( J:339267 )

• proportion of progressive sperm in the cauda epididymis is significantly lower than that in heterozygous control littermates

asthenozoospermia ( J:339267 )

• epididymal sperm exhibit severely impaired motility; the proportion of motile sperm in the cauda epididymis is only ~10% versus 40% in heterozygous control littermates

• evaluation of sperm motility velocity showed a significant reduction in VAP (average path velocity), VSL (straight-line velocity) and VCL (curvilinear velocity)

abnormal spermiogenesis ( J:339267 )

• SYPL1-mediated formation of saccular elements and their sequestration within the cytoplasmic droplet (CD) is impaired during late steps of spermiogenesis

• step 14-15 spermatids exhibit large membrane-bound vacuolar structures along with a few normal-looking small vesicles, unlike stage-matched control spermatids where a large cluster of small spherical vesicles is seen in the cytoplasm and on one side of the mitochondrial sheath

• as spermatids progress to step 16, no flattened saccules are found in the CD region and only rare spherical vesicles are present, unlike in control spermatids where numerous flattened or dilated straight or curved saccular elements appear in the CD region

• VAMP3 function is altered leading to uncontrolled vesicular fusion that results in large vacuolar structures in the cytoplasm of late spermatids and in an empty CD phenotype

male infertility ( J:339267 )

• 8 of 10 males tested are completely infertile

• however, mating behavior is normal

reduced male fertility ( J:339267 )

• 2 of 10 males tested produce only 1 litter each of reduced size during a 5-month breeding period

teratozoospermia ( J:339267 )

• sperm show a defect in cytoplasmic droplet (CD) formation; the CD region is greatly reduced in size and devoid of saccular elements in step16 spermatids and epididymal sperm

• however, the sperm mitochondrial sheath, acrosomes, nuclei and flagellar components are normal

abnormal sperm connecting piece morphology ( J:339267 )

• most cauda epididymal sperm exhibit a bent head at the neck region

abnormal sperm midpiece morphology ( J:339267 )

• cauda epididymal sperm show a bent midpiece phenotype

• % of bent midpiece sperm is significantly higher than that of controls in testes, caput and cauda epididymides

kinked sperm flagellum ( J:339267 )

• cauda epididymal sperm show abnormal flagellar angulation, mainly in a bent head at the neck region or bent midpiece phenotype

• % of angulated sperm is significantly higher than that of controls in testes, caput and cauda epididymides

• no flagellar angulation is observed in unreleased step 16 spermatids

abnormal sperm head morphology ( J:339267 )

• most cauda epididymal sperm exhibit a bent head at the neck region

• % of bent head sperm is significantly higher than that of controls in testes, caput and cauda epididymides

abnormal intracellular organelle morphology ( J:339267 )

• concomitant with a bent sperm head and bent midpiece phenotype, the sperm cytoplasmic droplet (CD) is greatly reduced in size and devoid of saccular elements in epididymal sperm

• both caput and cauda epididymal sperm lack the typically large, dilated CD regions seen in control littermates by phase contrast microscopy; no sperm bearing typical saccular elements in the CD region are detected by TEM

• further TEM analysis showed very few saccules, if any, in the CD region of step16 spermatids and epididymal sperm

• although reduced in size, the integrity of the CD region remains intact and an electron dense finely granular background is observed along with occasional small round vesicles

• key glycolytic enzymes HK1 (hexokinase 1) and PGK2 (phosphoglycerate kinase 2) are expressed at normal levels but fail to accumulate in the forming CD region of step 16 spermatids and epididymal sperm; both HK1 and PGK2 are absent in putative CD regions but are detectable in the cytoplasm along the flagellar midpiece and residual bodies, indicating that enrichment of protein components selectively to the CD is disrupted

decreased sperm progressive motility ( J:339267 )

• proportion of progressive sperm in the cauda epididymis is significantly lower than that in heterozygous control littermates

asthenozoospermia ( J:339267 )

• epididymal sperm exhibit severely impaired motility; the proportion of motile sperm in the cauda epididymis is only ~10% versus 40% in heterozygous control littermates

• evaluation of sperm motility velocity showed a significant reduction in VAP (average path velocity), VSL (straight-line velocity) and VCL (curvilinear velocity)

abnormal protein level ( J:339267 )

• Western blot analysis showed decreased protein levels of HK1 and PGK2 in caput epididymal sperm, but not in testes

• VAMP3 expression is initiated in early round spermatids but is reduced in step 11-15 elongating spermatids and undetectable in both the CD region and residual body in step 16 spermatids; absence of VAMP3 is confirmed in isolated testicular and epididymal sperm

♀	phenotype observed in females
♂	phenotype observed in males
N	normal phenotype

♀	phenotype observed in females
♂	phenotype observed in males
N	normal phenotype

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