title: hnRNP A1 contacts exon 5 to promote exon 6 inclusion of apoptotic Fas gene.
abstract: Fas is a transmembrane cell surface protein recognized by Fas ligand (FasL). When FasL binds to Fas, the target cells undergo apoptosis. A soluble Fas molecule that lacks the transmembrane domain is produced from skipping of exon 6 encoding this region in alternative splicing procedure. The soluble Fas molecule has the opposite function of intact Fas molecule, protecting cells from apoptosis. Here we show that knockdown of hnRNP A1 promotes exon 6 skipping of Fas pre-mRNA, whereas overexpression of hnRNP A1 reduces exon 6 skipping. Based on the bioinformatics approach, we have hypothesized that hnRNP A1 functions through interrupting 5' splice site selection of exon 5 by interacting with its potential binding site close to 5' splice site of exon 5. Consistent with our hypothesis, we demonstrate that mutations of the hnRNP A1 binding site on exon 5 disrupted the effects of hnRNP A1 on exon 6 inclusion. RNA pull-down assay and then western blot analysis with hnRNP A1 antibody prove that hnRNP A1 contacts the potential binding site RNA sequence on exon 5 but not the mutant sequence. In addition, we show that the mutation of 5' splice site on exon 5 to a less conserved sequence destructed the effects of hnRNP A1 on exon 6 inclusion. Therefore we conclude that hnRNP A1 interacts with exon 5 to promote distal exon 6 inclusion of Fas pre-mRNA. Our study reveals a novel alternative splicing mechanism of Fas pre-mRNA.
authors: School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea.
authors: Hyun kyung
authors: Hk
authors: Oh
authors: Eunkyung
authors: E
authors: Lee
authors: Ha Na
authors: HN
authors: Jang
authors: Jaehoon
authors: J
authors: Lee
authors: Heegyum
authors: H
authors: Moon
authors: Zhi
authors: Z
authors: Sheng
authors: Youngsoo
authors: Y
authors: Jun
authors: Tiing Jen
authors: TJ
authors: Loh
authors: Sunghee
authors: S
authors: Cho
authors: Jianhua
authors: J
authors: Zhou
authors: Michael R
authors: MR
authors: Green
authors: Xuexiu
authors: X
authors: Zheng
authors: Haihong
authors: H
authors: Shen
mesh_terms: D017398:Alternative Splicing; D017209:Apoptosis / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D005091:Exons; D053222:Fas Ligand Protein / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D011485:Protein Binding; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism; D022821:RNA Splice Sites; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D019014:fas Receptor / Q000235:genetics* / Q000378:metabolism
chemical_list: C491901:FAS protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D012322:RNA Precursors; D022821:RNA Splice Sites; D034741:RNA, Small Interfering; D019014:fas Receptor