title: hnRNP M facilitates exon 7 inclusion of SMN2 pre-mRNA in spinal muscular atrophy by targeting an enhancer on exon 7.
abstract: Spinal muscular atrophy (SMA) is an autosomal recessive genetic disease, which causes death of motor neurons in the anterior horn of the spinal cord. Genetic cause of SMA is the deletion or mutation of SMN1 gene, which encodes the SMN protein. Although SMA patients include SMN2 gene, a duplicate of SMN1 gene, predominant production of exon 7 skipped isoform from SMN2 pre-mRNA, fails to rescue SMA patients. Here we show that hnRNP M, a member of hnRNP protein family, when knocked down, promotes exon 7 skipping of both SMN2 and SMN1 pre-mRNA. By contrast, overexpression of hnRNP M promotes exon 7 inclusion of both SMN2 and SMN1 pre-mRNA. Significantly, hnRNP M promotes exon 7 inclusion in SMA patient cells. Thus, we conclude that hnRNP M promotes exon 7 inclusion of both SMN1 and SMN2 pre-mRNA. We also demonstrate that hnRNP M contacts an enhancer on exon 7, which was previously shown to provide binding site for tra2β. We present evidence that hnRNP M and tra2β contact overlapped sequence on exon 7 but with slightly different RNA sequence requirements. In addition, hnRNP M promotes U2AF65 recruitment on the flanking intron of exon 7. We conclude that hnRNP M promotes exon 7 inclusion of SMN1 and SMN2 pre-mRNA through targeting an enhancer on exon 7 through recruiting U2AF65. Our results provide a clue that hnRNP M is a potential therapeutic target for SMA.
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Sunghee
authors.initials: S
authors.lastname: Cho
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Heegyum
authors.initials: H
authors.lastname: Moon
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Tiing Jen
authors.initials: TJ
authors.lastname: Loh
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Huyn Kyung
authors.initials: HK
authors.lastname: Oh
authors.affiliation: Bio-Therapeutics Research Institute, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 363-883, Republic of Korea.
authors.forename: Sungchan
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Microbiology, Chonnam National University Medical School, Dong-gu, Gwangju, Republic of Korea.
authors.forename: Hyon E
authors.initials: HE
authors.lastname: Choy
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Woo Keun
authors.initials: WK
authors.lastname: Song
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Jang-Soo
authors.initials: JS
authors.lastname: Chun
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Xuexiu
authors.initials: X
authors.lastname: Zheng
authors.affiliation: School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea. Electronic address: haihongshen@gist.ac.kr.
authors.forename: Haihong
authors.initials: H
authors.lastname: Shen
mesh_terms: D000870:Anterior Horn Cells / Q000378:metabolism / Q000473:pathology; D018929:Cell Culture Techniques; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005786:Gene Expression Regulation; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M / Q000235:genetics / Q000378:metabolism*; D058990:Molecular Targeted Therapy; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D009134:Muscular Atrophy, Spinal / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology; D000072668:Splicing Factor U2AF; D055533:Survival of Motor Neuron 1 Protein / Q000378:metabolism; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D000072668:Splicing Factor U2AF; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein; C097083:TRA2B protein, human; C000607494:U2AF2 protein, human; D000068103:Serine-Arginine Splicing Factors
keywords: Exon 7; Pre-mRNA splicing; SMN2; Spinal muscular atrophy; hnRNP M