Distinct mRNA-Binding Proteins Interacting with Short Repeat Sequences of the 3′ UTR May Be Involved in the Post-Transcriptional Regulation of the Mouse Catalase Gene,Cas-1

摘要

ABSTRACTThe 3′ untranslated region (UTR) of the mouse catalase gene (Cas-1) is demonstrated to be an active site for specific protein interactions. We have identified two regions of theCas-13′ UTR mRNA that bind to distinct cytoplasmic proteins: one containing a (CA)31repeat with UA octomer (RNA 5) and another with a (U)15tract (RNA 6). RNA 5 interacts with one set of protein complexes (a, b, and c) whereas RNA 6 interacts with another (x, y, and z) in a sequence-specific manner. These RNA–protein complexes are development-, tissue-, and genotype-specific. The proteins involved in the two sets of complexes are different. Further characterization of the proteins involved in these interactions has revealed the presence of a single protein of ∼70 kD that binds RNA 5, and two proteins ∼38 kD and ∼47 kD that bind to RNA 6. The ∼70-kD and ∼38-kD proteins are also associated with the polysomal fractions and may play a role in the post-transcriptional regulation ofCas-1. Although the observed 3′ UTR RNA–protein interactions are hypothesized to be important in post-transcriptional regulation of this gene in rodents, specific RNA sequences and their associated proteins identified in this report would now permit the elucidation of the mechanisms of their action at