The neurospora CYT-18 protein suppresses defects in the phage T4 td intron by stabilizing the catalytically active structure of the intron core. |
| |
Authors: | G Mohr A Zhang J A Gianelos M Belfort A M Lambowitz |
| |
Institution: | Department of Molecular Genetics, Ohio State University, Columbus 43210. |
| |
Abstract: | The Neurospora CYT-18 protein, a tyrosyl-tRNA synthetase, which functions in splicing group I introns in mitochondria, promotes splicing of mutants of the distantly related bacteriophage T4 td intron. In an in vivo assay, wild-type CYT-18 protein expressed in E. coli suppressed mutations in the td intron's catalytic core. CYT-18-suppressible mutations were also suppressed by high Mg2+ or spermidine in vitro, suggesting they affect intron structure. Both the N- and C-terminal domains of CYT-18 are required for efficient splicing, but CYT-18 with a large C-terminal truncation retains some activity. Our results indicate that CYT-18 interacts with conserved structural features of group I introns, and they provide direct evidence that a protein promotes splicing by stabilizing the catalytically active structure of the intron RNA. |
| |
Keywords: | |
|
|