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鸟氨酸转氨甲酰酶(OTC)为肝脏线粒体中的酶,它的缺失是一种严重的性连锁的先天代谢缺陷,症状为氨中毒、蛋白质不耐性和精神迟缓,如是男性则早期夭亡。由于OTC在羊膜细胞中不表达,羊水中没有异常的代谢物,故无法用羊膜穿刺进行产前诊断,胎儿肝脏活组织检查具有危险性也不宜采用。作者将人体外周血淋巴细胞或培养的皮肤成纤维细胞中的DNA用几种不同的限制性核酸内切酶切割后,再以OTC的cDNA为探针进行Southern印迹杂交,观察出现的各个片段。发现其放射强度有着X染色体剂量效应,即具有1、2或4个X染色体的细胞系的DNA表现不同,表明反映的是X染色
Ornithine transcarbamylase (OTC) is an enzyme in the liver mitochondria whose absence is a serious, sexually linked, inborn error in metabolism with ammonia intoxication, protein intolerance and mental retardation, and early death in men . Because OTC is not expressed in amniotic cells, amniotic fluid is not abnormal metabolites, it can not be used amniocentesis for prenatal diagnosis, fetal liver biopsy is dangerous and should not be used. The authors cut DNA from human peripheral blood lymphocytes or cultured dermal fibroblasts using several different restriction endonucleases, followed by Southern blot hybridization with OTC cDNA probes to visualize the presence of each fragment. The radiation intensity was found to have an X-chromosome dose effect, ie the DNA performance of the cell lines with 1, 2 or 4 X chromosomes was different, indicating that the X-staining