title: OAZ-t/OAZ3 is essential for rigid connection of sperm tails to heads in mouse.
abstract: Polyamines are known to play important roles in the proliferation and differentiation of many types of cells. Although considerable amounts of polyamines are synthesized and stored in the testes, their roles remain unknown. Ornithine decarboxylase antizymes (OAZs) control the intracellular concentration of polyamines in a feedback manner. OAZ1 and OAZ2 are expressed ubiquitously, whereas OAZ-t/OAZ3 is expressed specifically in germline cells during spermiogenesis. OAZ-t reportedly binds to ornithine decarboxylase (ODC) and inactivates ODC activity. In a prior study, polyamines were capable of inducing a frameshift at the frameshift sequence of OAZ-t mRNA, resulting in the translation of OAZ-t. To investigate the physiological role of OAZ-t, we generated OAZ-t-disrupted mutant mice. Homozygous OAZ-t mutant males were infertile, although the polyamine concentrations of epididymides and testes were normal in these mice, and females were fertile. Sperm were successfully recovered from the epididymides of the mutant mice, but the heads and tails of the sperm cells were easily separated in culture medium during incubation. Results indicated that OAZ-t is essential for the formation of a rigid junction between the head and tail during spermatogenesis. The detached tails and heads were alive, and most of the headless tails showed straight forward movement. Although the tailless sperm failed to acrosome-react, the heads were capable of fertilizing eggs via intracytoplasmic sperm injection. OAZ-t likely plays a key role in haploid germ cell differentiation via the local concentration of polyamines.
authors.affiliation: TANAKA Project, Center for Advanced Science and Innovation, Osaka University, Suita, Osaka, Japan.
authors.forename: Keizo
authors.initials: K
authors.lastname: Tokuhiro
authors.forename: Ayako
authors.initials: A
authors.lastname: Isotani
authors.forename: Sadaki
authors.initials: S
authors.lastname: Yokota
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yano
authors.forename: Shigeru
authors.initials: S
authors.lastname: Oshio
authors.forename: Mika
authors.initials: M
authors.lastname: Hirose
authors.forename: Morimasa
authors.initials: M
authors.lastname: Wada
authors.forename: Kyoko
authors.initials: K
authors.lastname: Fujita
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Masaru
authors.initials: M
authors.lastname: Okabe
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Nishimune
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D005260:Female; D007248:Infertility, Male; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D013082:Sperm Tail / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000196:embryology / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C497526:Oaz3 protein, mouse