Mouse germ cell-less as an essential component for nuclear integrity.
A mouse homologue of the Drosophila melanogaster germ cell-less (mgcl-1) gene is expressed ubiquitously, and its gene product is localized to the nuclear envelope based on its binding to LAP2 beta (lamina-associated polypeptide 2 beta). To elucidate the role of mgcl-1, we analyzed two mutant mouse lines that lacked mgcl-1 gene expression. Abnormal nuclear morphologies that were probably due to impaired nuclear envelope integrity were observed in the liver, exocrine pancreas, and testis. In particular, functional abnormalities were observed in testis in which the highest expression of mgcl-1 was detected. Fertility was significantly impaired in mgcl-1-null male mice, probably as a result of severe morphological abnormalities in the sperm. Electron microscopic observations showed insufficient chromatin condensation and abnormal acrosome structures in mgcl-1-null sperm. In addition, the expression patterns of transition proteins and protamines, both of which are essential for chromatin remodeling during spermatogenesis, were aberrant. Considering that the first abnormality during the process of spermatogenesis was abnormal nuclear envelope structure in spermatocytes, the mgcl-1 gene product appears to be essential for appropriate nuclear-lamina organization, which in turn is essential for normal sperm morphogenesis and chromatin remodeling.
Kimura
Tohru
T
Department of Molecular Cell Biology, Research Institute for Microbial Diseases, Osaka University, Suita-shi, Osaka 565-0871, Japan.
Ito
Chizuru
C
Watanabe
Shoko
S
Takahashi
Tohru
T
Ikawa
Masahito
M
Yomogida
Kentaro
K
Fujita
Yukiko
Y
Ikeuchi
Megumi
M
Asada
Noriko
N
Matsumiya
Kiyomi
K
Okuyama
Akihiko
A
Okabe
Masaru
M
Toshimori
Kiyotaka
K
Nakano
Toru
T
D000818:Animals; D002467:Cell Nucleus / Q000502:physiology*; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure*; D005347:Fibroblasts; D018507:Gene Expression Regulation, Developmental; D007248:Infertility, Male / Q000235:genetics; D008099:Liver / Q000473:pathology; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010179:Pancreas / Q000473:pathology; D011479:Protamines / Q000235:genetics / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics; D013094:Spermatozoa / Q000473:pathology*; D013737:Testis / Q000473:pathology
D002843:Chromatin; C471550:Gcl protein, mouse; D009687:Nuclear Proteins; C513176:Prm1 protein, mouse; D011479:Protamines; C068621:protamine 2