A correlation with exon expression approach to identify cis-regulatory elements for tissue-specific alternative splicing

Nucleic Acids Res. 2007;35(14):4845-57. doi: 10.1093/nar/gkm485. Epub 2007 Jul 10.

Abstract

Correlation of motif occurrences with gene expression intensity is an effective strategy for elucidating transcriptional cis-regulatory logic. Here we demonstrate that this approach can also identify cis-regulatory elements for alternative pre-mRNA splicing. Using data from a human exon microarray, we identified 56 cassette exons that exhibited higher transcript-normalized expression in muscle than in other normal adult tissues. Intron sequences flanking these exons were then analyzed to identify candidate regulatory motifs for muscle-specific alternative splicing. Correlation of motif parameters with gene-normalized exon expression levels was examined using linear regression and linear splines on RNA words and degenerate weight matrices, respectively. Our unbiased analysis uncovered multiple candidate regulatory motifs for muscle-specific splicing, many of which are phylogenetically conserved among vertebrate genomes. The most prominent downstream motifs were binding sites for Fox1- and CELF-related splicing factors, and a branchpoint-like element acuaac; pyrimidine-rich elements resembling PTB-binding sites were most significant in upstream introns. Intriguingly, our systematic study indicates a paucity of novel muscle-specific elements that are dominant in short proximal intronic regions. We propose that Fox and CELF proteins play major roles in enforcing the muscle-specific alternative splicing program, facilitating expression of unique isoforms of cytoskeletal proteins critical to muscle cell function.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alternative Splicing*
  • Animals
  • Base Sequence
  • Binding Sites
  • Computational Biology / methods*
  • Conserved Sequence
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism
  • Exons
  • Gene Expression Profiling
  • Humans
  • Introns*
  • Muscle, Skeletal / metabolism
  • Myocardium / metabolism
  • RNA Precursors / chemistry
  • RNA, Messenger / chemistry
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / metabolism
  • Regulatory Sequences, Ribonucleic Acid*
  • Sequence Analysis, RNA / methods*
  • Transcription, Genetic

Substances

  • Cytoskeletal Proteins
  • RNA Precursors
  • RNA, Messenger
  • RNA-Binding Proteins
  • Regulatory Sequences, Ribonucleic Acid