Clinical and molecular characterizations of novel POU3F4 mutations reveal that DFN3 is due to null function of POU3F4 protein
Clinical and molecular characterizations of novel POU3F4 mutations reveal that DFN3 is due to null function of POU3F4 protein
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DOI：
10.1152/physiolgenomics.00100.2009
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发表时间：
2009-11-06
影响因子：
4.6
通讯作者：
Kim, Un-Kyung
中科院分区：
文献类型：
--
作者：
Lee, Hee Keun;Song, Mee Hyun;Kim, Un-Kyung
Lee HK, Song MH, Kang M, Lee JT, Kong K, Choi SJ, Lee KY, Venselaar H, friend G, Lee WH, Park HJ, Kwon TK, Bok J, Kim UK。新型POU3F4突变的临床和分子特征表明，DFN3是由于POU3F4蛋白的零功能。中国生物医学工程学报（英文版）39(5):591 - 591,2009。首次发表于2009年8月11日；doi: 10.1152 / physiolgenomics.00100.2009。- x连锁耳聋3型（DFN3）是最常见的x连锁遗传性耳聋形式，是由编码POU转录因子家族成员的POU3F4位点突变引起的。尽管有大量的临床评估和基因分析报告描述了新的POU3F4突变，但人们对这些突变如何影响POU3F4蛋白的正常功能并导致内耳畸形和耳聋知之甚少。在这里，我们描述了三个在DFN3位点分离的韩国耳聋家族中POU3F4基因的三个新突变及其临床特征。这三个突变导致POU同源结构域中高度保守的氨基酸残基的替换（p.a g329pro）或缺失（p.s 310del）或截断，消除两个dna结合结构域（p.a ala116fs）。为了更好地了解其内耳缺陷的分子机制，我们检测了正常和突变形式的POU3F4蛋白在C3H/10T1/2中胚层细胞中的行为。蛋白质模型和体外实验表明，这些突变对POU3F4蛋白的三级结构有害，并严重影响其结合DNA的能力。所有三个突变的POU3F4蛋白都不能反激活一个报告基因的表达。此外，当野生型和突变型蛋白共表达时，这三种蛋白都不能抑制野生型蛋白的转录活性。由于迄今为止报道的大多数DFN3突变都与编码POU3F4 DNA结合域的区域有关，我们的研究结果强烈表明，DFN3患者的耳聋主要是由于POU3F4的零功能。
Lee HK, Song MH, Kang M, Lee JT, Kong K, Choi SJ, Lee KY, Venselaar H, Vriend G, Lee WH, Park HJ, Kwon TK, Bok J, Kim UK. Clinical and molecular characterizations of novel POU3F4 mutations reveal that DFN3 is due to null function of POU3F4 protein. Physiol Genomics 39: 195-201, 2009. First published August 11, 2009; doi: 10.1152/physiolgenomics.00100.2009.-X-linked deafness type 3 (DFN3), the most prevalent X-linked form of hereditary deafness, is caused by mutations in the POU3F4 locus, which encodes a member of the POU family of transcription factors. Despite numerous reports on clinical evaluations and genetic analyses describing novel POU3F4 mutations, little is known about how such mutations affect normal functions of the POU3F4 protein and cause inner ear malformations and deafness. Here we describe three novel mutations of the POU3F4 gene and their clinical characterizations in three Korean families carrying deafness segregating at the DFN3 locus. The three mutations cause a substitution (p.Arg329Pro) or a deletion (p.Ser310del) of highly conserved amino acid residues in the POU homeodomain or a truncation that eliminates both DNA-binding domains (p.Ala116fs). In an attempt to better understand the molecular mechanisms underlying their inner ear defects, we examined the behavior of the normal and mutant forms of the POU3F4 protein in C3H/10T1/2 mesodermal cells. Protein modeling as well as in vitro assays demonstrated that these mutations are detrimental to the tertiary structure of the POU3F4 protein and severely affect its ability to bind DNA. All three mutated POU3F4 proteins failed to transactivate expression of a reporter gene. In addition, all three failed to inhibit the transcriptional activity of wild-type proteins when both wildtype and mutant proteins were coexpressed. Since most of the mutations reported for DFN3 thus far are associated with regions that encode the DNA binding domains of POU3F4, our results strongly suggest that the deafness in DFN3 patients is largely due to the null function of POU3F4.