Defects in modification of cytoplasmic and mitochondrial transfer RNAs are caused by single nuclear mutations |
| |
Authors: | Anita K Hopper Akemi H Furukawa Hung Dinh Pham Nancy C Martin |
| |
Institution: | Department of Biological Chemistry The Specialized Cancer Research Center The Milton S. Hershey Medical Center Hershey, Pennsylvania 17033 USA;Division of Molecular Biology Department of Biochemistry The University of Texas Health Science Center at Dallas 5323 Harry Hines Boulevard Dallas, Texas 75235 USA |
| |
Abstract: | Many nucleus-encoded mitochondrial enzymes differ in physical and chemical properties from analogous cytoplasmic enzymes, and it is therefore generally assumed that different genes encode analogous mitochondrial and cytoplasmic enzymes. However, our genetic studies show that for at least two different tRNA modifications, mutations in nuclear genes affect cytoplasmic as well as mitochondrial tRNAs. These studies utilize two yeast genes: TRM1 and TRM2. trm1 cells do not have the enzyme activity necessary to methylate guanosine to N2,N2-dimethylguanosine. trm2 is a new mutation that we describe here. trm2 cells are deficient in tRNA(uridine-5)methyltransferase, and hence contain tRNA lacking 5-methyluridine or ribothymidine. Other than lacking 5-methyluridine trm2 cells have no obvious physiological defect. These studies also show that the N2,N2-dimethylguanosine and 5-methyluridine modifications are not added to tRNA in an obligatory order, and that 5-methyluridine is not required for removal of intervening sequences from precursor tRNA. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|