TRANSFER-RNA BINDING-PROTEIN IN THE NUCLEUS OF SACCHAROMYCES-CEREVISIAE

A yeast nuclear protein that binds to tRNA was identified using a RNA mobility shift assay. Northwestern blotting and N-terminal sequencing experiments indicate that this tRNA-binding protein is identical to zu otin which has previously been shown to bind to Z-DNA [(1992) EMBO J. 11, 3787-3796]. Labeled tRNA and poly(dG-m(5)dC) stabilized in the Z-D NA form identify the same protein on a Northwestern blot. In a gel ret ardation assay poly(dG-m(5)dC) in the Z-form strongly diminishes the b inding of tRNA to zuotin. These studies establish that zuotin is able to bind to both tRNA and Z-DNA. Zuotin may be transiently associated w ith tRNA in the nucleus of yeast cells and play a role in its processi ng or transport to the cytoplasm.