Recent studies suggested that a small sub-population of embryonic stem (ES) cells exhibit 2-cell stage embryo-like (2-cell-like) features, including the reactivation of murine endogenous retrovirus with leucin transfer RNA primer, high histone mobility, and dispersed chromocenters. Furuta et al. investigated the organelle morphology of 2-cell-like cells using electron microscopy (Furuta et al. Lipid droplets are formed in 2-cell-like cells. pp. 79–81). They demonstrated the formation of a lipid droplet during the transition from ES cells to 2-cell-like cells, and proposed that these cells utilize a unique energy storage and production pathway.
Previous reports suggested the involvement of alpha-tubulin N-acetyltransferase 1 (ATAT1) in flagella formation in spermatozoa; however, whether ATAT1 is expressed in flagella and involved in spermatozoa maturation and capacitation remains to be elucidated. Yanai et al. evaluated the expression of ATAT1 in the male reproductive system in mice using immunostaining and western blotting (Yanai et al. Expression and localization of alpha-tubulin N-acetyltransferase 1 in the reproductive system of male mice. pp. 59–66). The localization of ATAT1 protein in the male germline was detected during spermiogenesis as well as spermatozoa maturation. Therefore, these results suggest that ATAT1 might be involved not only in flagella formation, but also in the acetylation process during spermatozoa maturation and capacitation.
Cover Story: Cluster of differentiation 9 (CD9) forms a complex with CD81, and is a member of the tetraspanin superfamily. Cd9 and Cd81 are highly expressed in breast cancer cells, but their expression in healthy mammary glands remains unclear. Horiguchi et al. reported expression of Cd9 and Cd81 in mammary epithelial cells, with expression levels correlating with mammary gland development (Horiguchi et al. Expression and functions of cluster of differentiation 9 and 81 in rat mammary epithelial cells, pp. 515–522). To examine the functional roles of CD9 and CD81, Horiguchi et al. knocked down Cd9 and Cd81 gene expression using small interfering RNAs (siRNAs) in isolated CD9-positive mammary epithelial cells. They found that siRNAs against Cd9 and Cd81 inhibited estrogen-induced mammary epithelial cell proliferation. These findings provide novel insights into mammary epithelial cell proliferation during pregnancy and lactation, as well as in pathological processes associated with breast cancer.
Green Fluorescent Protein as a Novel Vital Marker in Transgenic Mouse
Released: October 20, 2010 | Volume 43 Issue 6 Pages j19-j25
Masaru OKABE, Masahito IKAWA, Shuichi YAMADA, Tomoko NAKANISHI, Tadashi BABA
Follicular Growth and Atresia in Mammalian Ovaries: Regulation by Survival and Death of Granulosa Cells
Released: March 22, 2012 | Volume 58 Issue 1 Pages 44-50
Fuko MATSUDA, Naoko INOUE, Noboru MANABE, Satoshi OHKURA
Mammary Growth and Regression -Regulation of Milk Synthesis-
Released: October 20, 2010 | Volume 42 Issue 6 Pages j143-j150