Mitochondrial Proteins Interacting with Guide RNAs (RESEARCH FACILITY OF NUCLEIC ACIDS)

Abstract

In mitochondria of kinetoplastid protozoa, many of mRNA transcripts of structure genes are modified within coding regions in a posttranscriptional processing characterized by the insertion and, less frequently, the deletion of uridine residues. This process, known as RNA editing, involves small RNA molecules, guide RNAs, which specify the sequence information required. The aim of this study was to identify mitochondrial proteins that are in direct physical contacts with gRNA molecules, thereby possibly responsible for the RNA editing reaction. Using an ultraviolet light-induced cross-linking technique and a gel retardation assay, seven proteins with apparent molecular weights ranging from 20 to 67 kDa in size were identified. Four species of the proteins were purified with DEAE-cellulose and phosphocellulose column chromatographies. One of them probably contacts with 3’ poly(U)n tails of the gRNA molecules because the binding of the protein was sensitive to the presence of oligo (U)n.