title: Possible role of ZPAC, zygote-specific proteasome assembly chaperone, during spermatogenesis in the mouse.
abstract: In the mammalian testis, the ubiquitin-proteasome system plays important roles in the process that promotes the formation of mature sperm. We recently identified zygote-specific proteasome assembly chaperone (ZPAC), which is specifically expressed in the mouse gonads and zygote. ZPAC mediates a unique proteasome assembly pathway in the zygote, but the expression profile and function of ZPAC in the testis is not fully understood. In this study, we investigated the possible role of ZPAC during mouse spermatogenesis. First, we analyzed the expression of ZPAC and 20S proteasome subunit α4/PSMA7 in the adult mouse testis. ZPAC and α4 were expressed in spermatogonia, spermatocytes, and round spermatids. In elongating spermatids, ZPAC was expressed until step 10, whereas expression of α4 persisted until step 12. We then examined the expression profile of ZPAC and α4 in a mouse model of experimental unilateral cryptorchidism. Consistent with appearance of morphologically impaired germ cells following cryptorchidism, the ZPAC protein level was significantly decreased at 4 days post induction of experimental cryptorchidism (D4) compared with the intact testis, although the amount of α4 protein persisted at least until D10. Moreover, intense ZPAC staining was co-localized with staining of annexin V, an early indicator of apoptosis in mammalian cells, in germ cells of cryptorchid testis, but ZPAC was also expressed in germ cells showing no detectable expression of annexin V. These results suggest that ZPAC plays a role during spermatogenesis and raises the possibility that 20S proteasome mediated by ZPAC may be involved in the regulation of germ cell survival during spermatogenesis.
authors.affiliation: Laboratory of Molecular Developmental Biology, Graduate School of Biology-Oriented Science and Technology, Kinki University, Wakayama 649-6493, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Shimizu
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Ueno
authors.forename: Ena
authors.initials: E
authors.lastname: Kurita
authors.forename: Seung-Wook
authors.initials: SW
authors.lastname: Shin
authors.forename: Takuji
authors.initials: T
authors.lastname: Nishihara
authors.forename: Tomoko
authors.initials: T
authors.lastname: Amano
authors.forename: Masayuki
authors.initials: M
authors.lastname: Anzai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kishigami
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kato
authors.forename: Tasuku
authors.initials: T
authors.lastname: Mitani
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hosoi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000235:genetics; D003456:Cryptorchidism / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018832:Molecular Chaperones / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics*; D013094:Spermatozoa / Q000502:physiology; D013737:Testis / Q000378:metabolism; D015053:Zygote / Q000378:metabolism
chemical_list: D018832:Molecular Chaperones; D009687:Nuclear Proteins; C000597074:ZPAC protein, mouse; D046988:Proteasome Endopeptidase Complex