Underwood JG, Boutz PL, Dougherty JD, Stoilov P, Black DL.
Homologues of the Caenorhabditis elegans Fox-1 protein are neuronal splicing regulators in mammals.
Mol. Cell. Biol.
A vertebrate homologue of the Fox-1 protein from C. elegans was recently shown to bind to the element GCAUG and to act as an inhibitor of alternative splicing patterns in muscle. The element UGCAUG is a splicing enhancer element found downstream of numerous neuron-specific exons. We show here that mouse Fox-1 (mFox-1) and another homologue, Fox-2, are both specifically expressed in neurons in addition to muscle and heart. The mammalian Fox genes are very complex transcription units that generate transcripts from multiple promoters and with multiple internal exons whose inclusion is regulated. These genes produce a large family of proteins with variable N and C termini and internal deletions. We show that the overexpression of both Fox-1 and Fox-2 isoforms specifically activates splicing of neuronally regulated exons. This splicing activation requires UGCAUG enhancer elements. Conversely, RNA interference-mediated knockdown of Fox protein expression inhibits splicing of UGCAUG-dependent exons. These experiments show that this large family of proteins regulates splicing in the nervous system. They do this through a splicing enhancer function, in addition to their apparent negative effects on splicing in vertebrate muscle and in worms.
Brain / metabolism
Caenorhabditis elegans Proteins / genetics
Caenorhabditis elegans Proteins / physiology*
Carrier Proteins / genetics
Carrier Proteins / physiology*
Cross-Linking Reagents / pharmacology
Enhancer Elements, Genetic
Fibronectins / metabolism
Gene Expression Regulation
Hippocampus / metabolism
Muscles / metabolism
Neurons / metabolism*
Plasmids / metabolism
Promoter Regions, Genetic
Protein Structure, Tertiary
RNA Splicing Factors
RNA, Messenger / metabolism
RNA, Small Interfering / metabolism
RNA-Binding Proteins / genetics
RNA-Binding Proteins / physiology*
Repressor Proteins / genetics
Repressor Proteins / physiology*
Reverse Transcriptase Polymerase Chain Reaction
BIOCHEMISTRY & MOLECULAR BIOLOGY
||cDNA library of mixed-stage C. elegans for yeast two-hybrid screening (RDB1864)