Igakura T, Kadomatsu K, Kaname T, Muramatsu H, Fan Q W, Miyauchi T, Toyama Y, Kuno N, Yuasa S, Takahashi M, Senda T, Taguchi O, Yamamura K, Arimura K, Muramatsu T
Department of Biochemistry, Nagoya University School of Medicine, Japan.
Dev Biol. 1998 Feb 15;194(2):152-65. doi: 10.1006/dbio.1997.8819.
Basigin is a highly glycosylated transmembrane protein with two immunoglobulin-like domains. We generated mutant mice lacking the basigin gene (Bsg) by gene targeting. Bsg (-/-) embryos developed normally during preimplantation stages. However, the majority of Bsg (-/-) embryos died around the time of implantation. At this time, basigin mRNA was strongly expressed in the trophectoderm, embryo proper, and uterine endometrium of Bsg (+/+) mice. These results suggest that basigin is involved in intercellular recognition during implantation. Embryos which survived the critical period yielded Bsg (-/-) mutant mice. Half of the mutant mice died before 1 month after birth, due to interstitial pneumonia. The surviving adult mutant mice were small and sterile. Spermatogenesis was arrested in the mutant mice. Most of the spermatocytes in the Bsg (-/-) mouse were arrested and degenerated at the metaphase of the first meiosis, and only a small number differentiated to step 1 spermatids. In the female mutants, the ovaries and genital tract were morphologically normal, and the defect was probably in the capability of implantation of the uterus. In conclusion, basigin is an important cell-surface molecule involved in early embryogenesis and reproduction.
基底结合素是一种具有两个免疫球蛋白样结构域的高度糖基化跨膜蛋白。我们通过基因打靶技术构建了缺乏基底结合素基因（Bsg）的突变小鼠。Bsg（-/-）胚胎在植入前阶段发育正常。然而，大多数Bsg（-/-）胚胎在植入时左右死亡。此时，基底结合素mRNA在Bsg（+/ +）小鼠的滋养外胚层、胚胎本体和子宫内膜中强烈表达。这些结果表明基底结合素参与植入过程中的细胞间识别。在关键时期存活下来的胚胎产生了Bsg（-/-）突变小鼠。一半的突变小鼠在出生后1个月内死亡，原因是间质性肺炎。存活的成年突变小鼠体型小且不育。突变小鼠的精子发生停滞。Bsg（-/-）小鼠中的大多数精母细胞在第一次减数分裂中期停滞并退化，只有少数分化为1级精子细胞。在雌性突变体中，卵巢和生殖道形态正常，缺陷可能在于子宫的植入能力。总之，基底结合素是参与早期胚胎发育和生殖的重要细胞表面分子。
