RIT1, A TRANSFER-RNA BACKBONE-MODIFYING ENZYME THAT MEDIATES INITIATOR AND ELONGATOR TRANSFER-RNA DISCRIMINATION
RIT1, A TRANSFER-RNA BACKBONE-MODIFYING ENZYME THAT MEDIATES INITIATOR AND ELONGATOR TRANSFER-RNA DISCRIMINATION
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DOI：
10.1016/0092-8674(94)90262-3
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发表时间：
1994-11-04
期刊：
影响因子：
64.5
通讯作者：
BYSTROM, AS
中科院分区：
文献类型：
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作者：
ASTROM, SU;BYSTROM, AS
使用酵母中的遗传筛选，目的是确定在翻译过程中的启动子和延伸子甲硫氨酸tRNA歧视参与的细胞因子，我们已经确定了一个突变，取消了对延伸子甲硫氨酸tRNA的要求。受影响的基因，我们称之为起始tRNA基因的核糖基化或RIT 1，编码2 '-O-核糖基磷酸转移酶。该酶使用5-磷酸核糖基-1 '-焦磷酸作为修饰供体，仅修饰64位的起始tRNA。由于起始tRNA参与rit 1菌株中翻译的起始和延伸，我们得出结论，在蛋白质合成期间，2 '-O-核糖基磷酸修饰将起始tRNA与延伸tRNA区分开来。修饰酶被证明识别茎环IV区，这是唯一的真核细胞质起始tRNA。
Using a genetic screen in yeast aimed at identifying cellular factors involved in initiator and elongator methionine tRNA discrimination in the translational process, we have identified a mutation that abolish the requirement for elongator methionine tRNA. The gene affected, which we call the ribosylation of the initiator tRNA gene or RIT1, encodes a 2'-O-ribosyl phosphate transferase. This enzyme modifies exclusively the initiator tRNA in position 64 using 5-phosphoribosyl-1'-pyrophosphate as the modification donor. As the initiator tRNA participates both in the initiation and elongation of translation in a rit1 strain, we conclude that the 2'-O-ribosyl phosphate modification discriminates the initiator tRNAs from the elongator tRNAs during protein synthesis. The modification enzyme was shown to recognize the stem-loop IV region that is unique in eukaryotic cytoplasmic initiator tRNAs.