title: Fox-3 and PSF interact to activate neural cell-specific alternative splicing.
abstract: Fox-1 family (Fox) proteins, which consist of Fox-1 (A2BP1), Fox-2 (Rbm9) and Fox-3 (NeuN) in mammals, bind to the RNA element UGCAUG and regulate alternative pre-mRNA splicing. However the mechanisms for Fox-regulated splicing are largely unknown. We analyzed the expression pattern of the three Fox proteins as well as neural cell-specific alternative splicing of a cassette exon N30 of nonmuscle myosin heavy chain (NMHC) II-B in the mouse central nervous system. Histological and biochemical analyses following fluorescence-activated cell sorting demonstrate a positive correlation of N30 inclusion and Fox-3 expression. Further, we identified polypyrimidine tract binding protein-associated splicing factor (PSF) as an interacting protein with Fox-3 by affinity-chromatography. In cultured cells, enhancement of N30 inclusion by Fox-3 depends on the presence of PSF. PSF enhances N30 inclusion in a UGCAUG-dependent manner, although it does not bind directly to this element. Fox-3 is recruited to the UGCAUG element downstream of N30 in the endogenous NMHC II-B transcript in a PSF-dependent manner. This study is the first to identify PSF as a coactivator of Fox proteins and provides evidence that the Fox-3 and PSF interaction is an integral part of the mechanism by which Fox proteins regulate activation of alternative exons via a downstream intronic enhancer.
authors.affiliation: Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Kee K
authors.initials: KK
authors.lastname: Kim
authors.forename: Yong C
authors.initials: YC
authors.lastname: Kim
authors.forename: Robert S
authors.initials: RS
authors.lastname: Adelstein
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Kawamoto
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002490:Central Nervous System / Q000378:metabolism; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors / Q000378:metabolism; D051379:Mice; D018995:Myosin Heavy Chains / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D024501:Nonmuscle Myosin Type IIB / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism*; D000072670:PTB-Associated Splicing Factor; D012313:RNA / Q000378:metabolism; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; C485809:Foxj2 protein, mouse; D009419:Nerve Tissue Proteins; C492380:NeuN protein, mouse; D009687:Nuclear Proteins; D000072670:PTB-Associated Splicing Factor; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; C465036:Rbfox1 protein, mouse; D012313:RNA; D024501:Nonmuscle Myosin Type IIB; C103815:nonmuscle myosin type IIB heavy chain; D018995:Myosin Heavy Chains