Cardiac elav-type RNA-binding protein (ETR-3) binds to RNA CUG repeats expanded in myotonic dystrophy

Hum Mol Genet. 1999 Jan;8(1):53-60. doi: 10.1093/hmg/8.1.53.

Abstract

Myotonic dystrophy (DM) is a neuromuscular disorder associated with CTG triplet repeat expansion in the myotonin protein kinase gene ( DMPK ). We previously proposed a hypothesis suggesting that the expanded CUG repeats sequester specific RNA-binding proteins and that such a sequestration results in abnormal RNA processing of several RNAs containing CUG repeats in multiple tissues affected in patients with DM. One of the members of the CUG-binding proteins, CUG-BP, has been identified previously. Here we describe the second member of this family, elav -type ribonucleoprotein (ETR-3), which is highly expressed in heart and is able to interact with CUG repeats. Screening of a mouse liver cDNA library with a CUG-BP probe identified two mETR-3 cDNAs. Two additional cDNAs from mouse heart were amplified by RT-PCR. These cDNAs differ by several insertions/deletions and might be generated via alternative splicing. Mouse ETR-3 has a mol. wt of 50 kDa and displays a high level of homology to CUG-BP protein. The organization of the RNA-binding domains (RBDs) within the ETR-3 molecule is similar to one within CUG-BP. A study of mETR-3 RNA-binding activity showed that the mETR-3 binds to (CUG)8repeats. Sequence analysis of mETR-3 indicates the presence of several CUG repeats within the mETR-3 mRNA. Both CUG-BP and mETR-3 bind to mETR-3 mRNA via CUG repeats, suggesting the possible involvement of CUG-BP-like proteins in the regulation of mETR-3 processing. Analysis of the tissue distribution of ETR-3 showed that in human cells, ETR-3 mRNA is highly expressed in heart, but is undetectable in other tissues examined. Our results suggest the existence of a family of proteins that bind to CUG repeats and might be affected in DM by expansion of CUG repeats.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites / genetics
  • CELF Proteins
  • DNA Primers / genetics
  • DNA, Complementary / genetics
  • HeLa Cells
  • Humans
  • In Vitro Techniques
  • Mice
  • Molecular Sequence Data
  • Myocardium / metabolism
  • Myotonic Dystrophy / genetics*
  • Myotonic Dystrophy / metabolism*
  • Nerve Tissue Proteins
  • RNA / genetics*
  • RNA / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Trinucleotide Repeat Expansion*

Substances

  • CELF Proteins
  • CELF2 protein, human
  • DNA Primers
  • DNA, Complementary
  • Nerve Tissue Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • RNA

Associated data

  • GENBANK/Y18298