title: T396I mutation of mouse Sufu reduces the stability and activity of Gli3 repressor.
abstract: Hedgehog signaling is primarily transduced by two transcription factors: Gli2, which mainly acts as a full-length activator, and Gli3, which tends to be proteolytically processed from a full-length form (Gli3FL) to an N-terminal repressor (Gli3REP). Recent studies using a Sufu knockout mouse have indicated that Sufu is involved in regulating Gli2 and Gli3 activator and repressor activity at multiple steps of the signaling cascade; however, the mechanism of specific Gli2 and Gli3 regulation remains to be elucidated. In this study, we established an allelic series of ENU-induced mouse strains. Analysis of one of the missense alleles, SufuT396I, showed that Thr396 residue of Sufu played a key role in regulation of Gli3 activity. SufuT396I/T396I embryos exhibited severe polydactyly, which is indicative of compromised Gli3 activity. Concomitantly, significant quantitative reductions of unprocessed Gli3 (Gli3FL) and processed Gli3 (Gli3REP) were observed in vivo as well as in vitro. Genetic experiments showed that patterning defects in the limb buds of SufuT396I/T396I were rescued by a constitutive Gli3REP allele (Gli3∆699), strongly suggesting that SufuT396I reduced the truncated Gli3 repressor. In contrast, SufuT396I qualitatively exhibited no mutational effects on Gli2 regulation. Taken together, the results of this study show that the Thr396 residue of Sufu is specifically required for regulation of Gli3 but not Gli2. This implies a novel Sufu-mediated mechanism in which Gli2 activator and Gli3 repressor are differentially regulated.
authors.affiliation: Mutagenesis and Genomics Team, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Makino
authors.affiliation: Department of Molecular Genetics, University of Toronto and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Olena
authors.initials: O
authors.lastname: Zhulyn
authors.affiliation: Department of Molecular Genetics, University of Toronto and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Rong
authors.initials: R
authors.lastname: Mo
authors.affiliation: Department of Molecular Genetics, University of Toronto and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Vijitha
authors.initials: V
authors.lastname: Puviindran
authors.affiliation: Department of Molecular Genetics, University of Toronto and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Mutagenesis and Genomics Team, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Murata
authors.affiliation: Mutagenesis and Genomics Team, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Fukumura
authors.affiliation: Mutagenesis and Genomics Team, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishitsuka
authors.affiliation: Mutagenesis and Genomics Team, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Kotaki
authors.affiliation: Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Matsumaru
authors.affiliation: Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, Tsukuba, Ibaraki, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Ishii
authors.affiliation: Department of Molecular Genetics, University of Toronto and Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Hui
authors.affiliation: Mutagenesis and Genomics Team, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Gondo
mesh_terms: D000818:Animals; D019521:Body Patterning; D005121:Extremities / Q000254:growth & development; D007532:Isoleucine / Q000378:metabolism; D051741:Kruppel-Like Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D051379:Mice; D020125:Mutation, Missense; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D017689:Polydactyly / Q000196:embryology / Q000235:genetics; D055550:Protein Stability; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism; D000075746:Zinc Finger Protein Gli2; D000074290:Zinc Finger Protein Gli3
chemical_list: C000618551:Gli2 protein, mouse; C465571:Gli3 protein, mouse; D051741:Kruppel-Like Transcription Factors; D009419:Nerve Tissue Proteins; D012097:Repressor Proteins; C490763:Sufu protein, mouse; D000075746:Zinc Finger Protein Gli2; D000074290:Zinc Finger Protein Gli3; D007532:Isoleucine; D013912:Threonine