朊病毒研究的现状

Following the Study about Prions

朊病毒疾病是人和动物中的一种传染性、散发性和遗传性的神经退行性脑病。到目前为止，关于此病的致病机制并不十分清楚。但有研究表明该病是由一种正常蛋白PrP的不正常折叠形式在大脑中积聚所致。许多哺乳动物和鸟类的朊病毒基因和氨基酸序列都已被分析，而且传染源的部分性质已经被阐明。朊病毒疾病的传染和潜伏期在人和动物中有很大差异，一些变异与疾病的自发性、易感性和抵抗性有关。为得到关于朊病毒更多的信息，已对其基因两端进行了大范围的DNA测序分析。至于正常细胞蛋白PrP的生理功能，现在也并不确定。

：Prion diseases is a kind of infectious，sporadic or genetic neurodegenerative disorders in both humans and animals，including scrapie in sheep，BSE in cattle and CJD in humans． To date，the mechanism of the disease is still unclear，but studies indicate the disease are caused by the accumulation of a abnormal isoform of a normal cellular protein －－PrPc in the brain． PrP gene sequence and amino acid sequence have been analyzed in many species of mammals and birds and the nature of the infectious agent has been partially demonstrated． The infection and incubation of this disease are very different in animals and humans． Some mutations are found relative to the spontaneity susceptibility and resistance to the disease． In order to get the whole locus of PrP  large－scale DNA sequencing has been used to identify adjacent perhaps functionally related genes． The physiological function of the normal cellular isoform－－ PrPc is unknown but some studies suggest PrPc has an activity like that of superoxide dismutaseand other evidence indicate PrPc can prevent neuronal cell－line death．