Two closely related ubiquitin C-terminal hydrolase isozymes function as reciprocal modulators of germ cell apoptosis in cryptorchid testis.
The experimentally induced cryptorchid mouse model is useful for elucidating the in vivo molecular mechanism of germ cell apoptosis. Apoptosis, in general, is thought to be partly regulated by the ubiquitin-proteasome system. Here, we analyzed the function of two closely related members of the ubiquitin C-terminal hydrolase (UCH) family in testicular germ cell apoptosis experimentally induced by cryptorchidism. The two enzymes, UCH-L1 and UCH-L3, deubiquitinate ubiquitin-protein conjugates and control the cellular balance of ubiquitin. The testes of gracile axonal dystrophy (gad) mice, which lack UCH-L1, were resistant to cryptorchid stress-related injury and had reduced ubiquitin levels. The level of both anti-apoptotic (Bcl-2 family and XIAP) and prosurvival (pCREB and BDNF) proteins was significantly higher in gad mice after cryptorchid stress. In contrast, Uchl3 knockout mice showed profound testicular atrophy and apoptotic germ cell loss after cryptorchid injury. Ubiquitin level was not significantly different between wild-type and Uchl3 knockout mice, whereas the levels of Nedd8 and the apoptotic proteins p53, Bax, and caspase3 were elevated in Uchl3 knockout mice. These results demonstrate that UCH-L1 and UCH-L3 function differentially to regulate the cellular levels of anti-apoptotic, prosurvival, and apoptotic proteins during testicular germ cell apoptosis.
Department of Degenerative Neurological Disease, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, 187-8502, Japan.
Jungkee
J
Kwon
Yu-Lai
YL
Wang
Rieko
R
Setsuie
Satoshi
S
Sekiguchi
Yae
Y
Sato
Mikako
M
Sakurai
Mami
M
Noda
Shunsuke
S
Aoki
Yasuhiro
Y
Yoshikawa
Keiji
K
Wada
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D003456:Cryptorchidism / Q000150:complications*; D004195:Disease Models, Animal; D005854:Germ Cells / Q000201:enzymology / Q000473:pathology*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D013737:Testis / Q000201:enzymology* / Q000473:pathology; D025801:Ubiquitin / Q000378:metabolism; D043222:Ubiquitin Thiolesterase / Q000378:metabolism*
D007527:Isoenzymes; D025801:Ubiquitin; D043222:Ubiquitin Thiolesterase