Mullen J R, Kayne P S, Moerschell R P, Tsunasawa S, Gribskov M, Colavito-Shepanski M, Grunstein M, Sherman F, Sternglanz R
Department of Biochemistry, State University of New York, Stony Brook 11794.
EMBO J. 1989 Jul;8(7):2067-75. doi: 10.1002/j.1460-2075.1989.tb03615.x.
A gene from Saccharomyces cerevisiae has been mapped, cloned, sequenced and shown to encode a catalytic subunit of an N-terminal acetyltransferase. Regions of this gene, NAT1, and the chloramphenicol acetyltransferase genes of bacteria have limited but significant homology. A nat1 null mutant is viable but exhibits a variety of phenotypes, including reduced acetyltransferase activity, derepression of a silent mating type locus (HML) and failure to enter G0. All these phenotypes are identical to those of a previously characterized mutant, ard1. NAT1 and ARD1 are distinct genes that encode proteins with no obvious similarity. Concomitant overexpression of both NAT1 and ARD1 in yeast causes a 20-fold increase in acetyltransferase activity in vitro, whereas overexpression of either NAT1 or ARD1 alone does not raise activity over basal levels. A functional iso-1-cytochrome c protein, which is N-terminally acetylated in a NAT1 strain, is not acetylated in an isogenic nat1 mutant. At least 20 other yeast proteins, including histone H2B, are not N-terminally acetylated in either nat1 or ard1 mutants. These results suggest that NAT1 and ARD1 proteins function together to catalyze the N-terminal acetylation of a subset of yeast proteins.
来自酿酒酵母的一个基因已被定位、克隆、测序，并显示其编码一种N-末端乙酰转移酶的催化亚基。该基因（NAT1）的区域与细菌的氯霉素乙酰转移酶基因有有限但显著的同源性。nat1缺失突变体是可存活的，但表现出多种表型，包括乙酰转移酶活性降低、沉默交配型位点（HML）的去抑制以及无法进入G0期。所有这些表型都与先前鉴定的突变体ard1相同。NAT1和ARD1是不同的基因，它们编码的蛋白质没有明显的相似性。在酵母中同时过表达NAT1和ARD1会导致体外乙酰转移酶活性增加20倍，而单独过表达NAT1或ARD1都不会使活性超过基础水平。在NAT1菌株中N-末端被乙酰化的功能性异-1-细胞色素c蛋白，在同基因的nat1突变体中未被乙酰化。至少20种其他酵母蛋白，包括组蛋白H2B，在nat1或ard1突变体中N-末端都未被乙酰化。这些结果表明，NAT1和ARD1蛋白共同发挥作用，催化酵母蛋白亚群的N-末端乙酰化。
