Lawler Joseph F, Merkulov Gennady V, Boeke Jef D
Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
J Virol. 2002 Jan;76(1):346-54. doi: 10.1128/jvi.76.1.346-354.2002.
Ty1 is the most successful of the five endogenous yeast retrotransposons. The life cycle of Ty1 dictates that a number of nucleocapsid (NC)-facilitated events occur although the protein(s) responsible for these events has not been identified. The positioning of the NC peptide is conserved at the carboxy terminus of the Gag protein among most long terminal repeat (LTR)-containing retroelements. An analogous region of Ty1 that simultaneously encodes part of Gag, protease (PR), and the C-terminal p4 peptide was mutagenized. Some of these mutations result in smaller-than-normal virus-like particles (VLPs). The mutants were also found to impair an NC-like functionality contained within the amino terminus of the protease that is distinct and separable from its proteolytic activity. Remarkably, these mutants have distinct defects in reverse transcription.
Ty1是五种内源性酵母逆转录转座子中最为成功的一种。Ty1的生命周期表明，尽管尚未鉴定出负责这些事件的蛋白质，但一些核衣壳（NC）促进的事件会发生。在大多数含长末端重复序列（LTR）的逆转录元件中，NC肽的定位在Gag蛋白的羧基末端是保守的。对Ty1的一个类似区域进行了诱变，该区域同时编码Gag的一部分、蛋白酶（PR）和C末端p4肽。其中一些突变导致病毒样颗粒（VLP）比正常的小。还发现这些突变体损害了蛋白酶氨基末端所含的一种与蛋白水解活性不同且可分离的NC样功能。值得注意的是，这些突变体在逆转录过程中存在明显缺陷。
