MAK3 encodes an N-acetyltransferase whose modification of the L-A gag NH2 terminus is necessary for virus particle assembly.
MAK3 encodes an N-acetyltransferase whose modification of the L-A gag NH2 terminus is necessary for virus particle assembly.
复制标题
MAK3 编码 N-乙酰转移酶，其 L-A gag NH2 末端的修饰对于病毒颗粒组装是必需的。
DOI：
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发表时间：
1992
影响因子：
4.8
通讯作者：
R. Wickner
中科院分区：
文献类型：
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作者：
J. A. Tercero;R. Wickner
MAK 3基因是酿酒酵母L-A双链RNA病毒增殖所必需的。MAK 3编码与使核糖体蛋白S18的NH 2末端乙酰化的大肠杆菌rimI N-乙酰转移酶具有实质同源性的蛋白质，并且与一组N-乙酰转移酶共享共有序列。由L-A编码的病毒主要外壳蛋白的NH 2末端通常被封闭，但我们发现它在mak 3 -1突变体中未被封闭。从L-A的cDNA克隆产生的L-A病毒编码的蛋白质可以在野生型宿主中使L-A（+）-链变性，但不能在mak 3 -1突变株中。在颗粒级分中发现的主要外壳蛋白的量减少大于100倍，并且在总细胞提取物中的量减少5-10倍。一种修饰的β-半乳糖苷酶，其NH 2-末端为L-A编码的主要外壳蛋白的NH 2-末端13个残基，在野生型宿主中被阻断，但在mak 3 -1宿主中不被阻断。我们建议MAK 3编码N-乙酰转移酶，其L-A主要外壳蛋白NH 2末端的修饰对于病毒组装是必需的，并且未组装的外壳蛋白是不稳定的。
The MAK3 gene is necessary for propagation of the L-A double-stranded RNA virus of Saccharomyces cerevisiae. MAK3 encodes a protein with substantial homology to the Escherichia coli rimI N-acetyltransferase that acetylates the NH2 terminus of ribosomal protein S18, and shares consensus sequences with a group of N-acetyltransferases. The NH2 terminus of the viral major coat protein encoded by L-A is normally blocked, but we find that it is unblocked in a mak3-1 mutant. L-A virus-encoded proteins produced from a cDNA clone of L-A can encapsidate the L-A (+)-strands in a wild-type host, but not in a mak3-1 mutant strain. The amount of major coat protein found in the particle fraction is reduced greater than 100-fold, and the amount in the total cell extract is reduced 5-10-fold. A modified beta-galactosidase, having as its NH2-terminal the NH2-terminal 13 residues of the L-A-encoded major coat protein, is blocked in a wild-type host, but not in a mak3-1 host. We propose that MAK3 encodes an N-acetyltransferase whose modification of the L-A major coat protein NH2 terminus is essential for viral assembly, and that unassembled coat protein is unstable.