Ringvall M, Ledin J, Holmborn K, van Kuppevelt T, Ellin F, Eriksson I, Olofsson A M, Kjellen L, Forsberg E
Departments of Cell and Molecular Biology and Medical Biochemistry and Microbiology, Uppsala University, S-751 23 Uppsala, Sweden.
J Biol Chem. 2000 Aug 25;275(34):25926-30. doi: 10.1074/jbc.C000359200.
Heparan sulfate is a sulfated polysaccharide present on most cell surfaces and in the extracellular matrix. In vivo functions of heparan sulfate can be studied in mouse strains lacking enzymes involved in the biosynthesis of heparan sulfate. Glucosaminyl N-deacetylase/N-sulfotransferase (NDST) catalyzes the first modifying step in the biosynthesis of the polysaccharide. This bifunctional enzyme occurs in several isoforms. We here report that targeted gene disruption of NDST-1 in the mouse results in a structural alteration of heparan sulfate in most basement membranes as revealed by immunohistochemical staining of fetal tissue sections using antibodies raised against heparan sulfate. Biochemical analysis of heparan sulfate purified from fibroblast cultures, lung, and liver of NDST-1-deficient embryos demonstrated a dramatic reduction in N-sulfate content. Most NDST-1-deficient embryos survive until birth; however, they turn out to be cyanotic and die neonatally in a condition resembling respiratory distress syndrome. In addition, a minor proportion of NDST-1-deficient embryos die during the embryonic period. The cause of the embryonic lethality is still obscure, but incompletely penetrant defects of the skull and the eyes have been observed.
硫酸乙酰肝素是一种存在于大多数细胞表面和细胞外基质中的硫酸化多糖。可以在缺乏参与硫酸乙酰肝素生物合成的酶的小鼠品系中研究硫酸乙酰肝素的体内功能。氨基葡萄糖N-脱乙酰酶/N-磺基转移酶（NDST）催化多糖生物合成中的第一步修饰反应。这种双功能酶有几种同工型。我们在此报告，通过使用针对硫酸乙酰肝素产生的抗体对胎儿组织切片进行免疫组织化学染色发现，小鼠中NDST-1的靶向基因破坏导致大多数基底膜中硫酸乙酰肝素的结构改变。对从NDST-1缺陷胚胎的成纤维细胞培养物、肺和肝脏中纯化的硫酸乙酰肝素进行生化分析表明，N-硫酸盐含量显著降低。大多数NDST-1缺陷胚胎存活至出生；然而，它们会出现青紫，并在新生儿期死于类似呼吸窘迫综合征的病症。此外，一小部分NDST-1缺陷胚胎在胚胎期死亡。胚胎致死的原因仍然不明，但已观察到颅骨和眼睛存在不完全显性的缺陷。
