title: [Molecular pathogenesis of Waardenburg syndrome type II resulting from SOX10 gene mutation].
abstract: OBJECTIVE
  To explore the molecular mechanism of Waardenburg syndrome type II (WS2) resulting from SOX10 gene mutation E248fs through in vitro experiment.
  
  
  METHODS
  293T cells were transiently transfected with wild type (WT) SOX10 and mutant type (MT) E248fs plasmids. The regulatory effect of WT/MT SOX10 on the transcriptional activity of MITF gene and influence of E248fs on WT SOX10 function were determined with a luciferase activity assay. The DNA binding capacity of the WT/MT SOX10 with the promoter of the MITF gene was determined with a biotinylated double-stranded oligonucleotide probe containing the SOX10 binding sequence cattgtc to precipitate MITF and E248fs, respectively. The stability of SOX10 and E248fs were also analyzed.
  
  
  RESULTS
  As a loss-of-function mutation, the E248fs mutant failed to transactivate the MITF promoter as compared with the WT SOX10 (P<0.01), which also showed a dominant-negative effect on WT SOX10. The WT SOX10 and E248fs mutant were also able to bind specifically to the cattgtc motif in the MITF promoter, whereas E248fs had degraded faster than WT SOX10.
  
  
  CONCLUSIONS
  Despite the fact that the E248fs has a dominant-negative effect on SOX10, its reduced stability may down-regulate the transcription of MITF and decrease the synthesis of melanin, which may result in haploinsufficiency of SOX10 protein and cause the milder WS2 phenotype.
authors.affiliation: Department of Otorhinolaryngology, First Affiliated Hospital, Xinjiang Medical University, Urumqi, Xinjiang 830011, China; Department of Otorhinolaryngology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China; Department of Otorhinolaryngology, Xiangya Hospital, South China University, Changsha, Hunan 410008, China. Email: doczhent@163.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Chen
authors.forename: Yong
authors.initials: Y
authors.lastname: Feng
authors.forename: Minfei
authors.initials: M
authors.lastname: Qian
authors.forename: Jiping
authors.initials: J
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
mesh_terms: D006801:Humans; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics; D011401:Promoter Regions, Genetic; D055757:SOXE Transcription Factors / Q000235:genetics*; D014849:Waardenburg Syndrome / Q000209:etiology / Q000235:genetics*
chemical_list: C497234:MITF protein, human; D051739:Microphthalmia-Associated Transcription Factor; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors