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How does Proteoglycan synthesis by coraeal stromacytes respond to changes in environment around the cells?

珊瑚基质细胞合成的蛋白多糖如何响应细胞周围环境的变化？

基本信息

批准号：
11671762
负责人：
NAKAZAWA Kiyoshi
金额：
$ 1.34万
依托单位：
Meijo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

1. Immunohistochemically, keratan sulfate (KS) was first detected in corneal stroma on Day 6 of chick embryonic age, but this KS was undersulfated. The sulfation of KS increased on Day 8.2. When the stromacytes were cultured in vitro, the degree of sulfation of KS decreased markedly but the syntheses of KS backbone and core protein of KS proteoglycan were maintained. On the other hand, the sulfation of chondroitin sulfate increased.3. N-Acetylglucosaminyl sulfotransferase which may be involved in the sulfation of KS, was purified 887-fold with a 8.4% yield from 2-day-old chick corneas. The enzyme specifically transferred a sulfate to GlcNAc at the nonreducing end but not to internal GlcNAc. When the stromacytes were cultured in vitro, the activity of this enzyme specifically, markedly decreased.4. β-Glucuronyltransferase which may be involved in the elongation of chondroitin chain, was purified 389-fold with a 11% yield from 2-day-old chick corneas. This enzyme activity toward chondro-heptasaccharide was 10-fold higher than that toward chondro-pentasaccharide.5. β-Galactosyltransferase activity toward 6-sulfo-GlcNAcβl-3Gal which is the disaceharide unit of KS, was found in chick corneas. This enzyme may be a novel β-galactosyltransferase.6. Almost a whole of open reading frame (ORF) of cDNA of chick corneal chondroitin 6-sulfotransferase was determined for the nucleotide sequence and the predicted amino acid sequence, 3'-Side half of ORF of cDNA of chick coraeal chondroitin 4-sulfotransferase was determined for the nucleotide sequence and the predicted amino acid sequence.

1. 在鸡胚龄第6天的角膜基质中首次检测到硫酸角蛋白（KS），但该KS未充分硫酸化。在第8.2天，KS的磺化程度增加。当基质细胞体外培养时，KS的磺化程度明显降低，但KS主干和KS蛋白聚糖核心蛋白的合成得以维持。另一方面，硫酸软骨素的硫酸化程度增加。n -乙酰氨基葡萄糖基硫转移酶可能参与KS的磺化，从2日龄鸡角膜中纯化得到887倍，产率为8.4%。该酶特异性地将硫酸盐转移到GlcNAc的非还原端，而不是内部的GlcNAc。当基质细胞在体外培养时，这种酶的活性明显降低。β-葡萄糖醛基转移酶可能参与了软骨素链的延伸，从2日龄鸡角膜中纯化得到389倍，产率为11%。该酶对七糖软骨的活性比对五糖软骨的活性高10倍。在鸡角膜中发现了对KS的二糖化单位6-磺基glcnac βl- 3gal的β-半乳糖转移酶活性。该酶可能是一种新型β-半乳糖转移酶。鸡角膜软骨素6-亚砜转移酶cDNA的核苷酸序列和预测的氨基酸序列几乎是一个完整的开放阅读框（ORF），鸡角膜软骨素4-亚砜转移酶cDNA的核苷酸序列和预测的氨基酸序列的ORF的3'侧一半被确定。