Functional characterization of mutations in the myosin Vb gene associated with microvillus inclusion disease.
Functional characterization of mutations in the myosin Vb gene associated with microvillus inclusion disease.
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DOI：
10.1097/mpg.0b013e3181eea177
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发表时间：
2011-03
影响因子：
2.9
通讯作者：
van IJzendoorn SC
中科院分区：
文献类型：
--
作者：
Szperl AM;Golachowska MR;Bruinenberg M;Prekeris R;Thunnissen AM;Karrenbeld A;Dijkstra G;Hoekstra D;Mercer D;Ksiazyk J;Wijmenga C;Wapenaar MC;Rings EH;van IJzendoorn SC
微绒毛包涵性病（MVID）是一种罕见的常染色体隐性肠病，以难治性腹泻和吸收不良为特征。最近，在MVID患者中发现了多种MYO5B基因突变。有趣的是，一些MVID患者仅在一个等位基因（杂合子）上显示MYO5B突变或MYO5B基因没有突变，这表明需要进一步从功能上表征MYO5B突变的细胞生物学效应。对9例诊断为微绒毛包涵性疾病的患者的基因组DNA进行MYO5B突变筛选，并对2例患者的材料进行qPCR和免疫组织化学分析，以研究由此产生的细胞后果。我们首次证明MYO5B突变可以与肌球蛋白Vb mRNA表达的改变以及肌球蛋白Vb蛋白的异常亚细胞分布相关。此外，我们还发现，在MVID肠细胞中，典型的、由肌球蛋白Vb控制的rab11a和fip5阳性循环内体在细胞顶端细胞质中的积累被消除了，这表明肌球蛋白Vb的功能发生了改变。此外，我们报告了9名不同种族背景的MVID患者中8个新的MYO5B突变，包括复合杂合突变。我们的功能分析表明，MYO5B突变可能与肌球蛋白Vb蛋白和顶端循环内体的异常亚细胞分布有关，这些亚细胞分布与额外的复合杂合突变一起，显著加强了MYO5B与MVID之间的联系。
Microvillus inclusion disease (MVID) is a rare autosomal recessive enteropathy characterized by intractable diarrhea and malabsorption. Recently, various MYO5B gene mutations have been identified in MVID patients. Interestingly, several MVID patients showed only a MYO5B mutation in one allele (heterozygous) or no mutations in the MYO5B gene, illustrating the need to further functionally characterize the cell biological effects of the MYO5B mutations. The genomic DNA of nine patients diagnosed with microvillus inclusion disease was screened for MYO5B mutations, and qPCR and immunohistochemistry on the material of two patients was performed to investigate resultant cellular consequences. We demonstrate for the first time that MYO5B mutations can be correlated with altered myosin Vb mRNA expression and with an aberrant subcellular distribution of the myosin Vb protein. Moreover, we demonstrate that the typical and myosin Vb–controlled accumulation of rab11a-and FIP5-positive recycling endosomes in the apical cytoplasm of the cells is abolished in MVID enterocytes, which is indicative for altered myosin Vb function. Also, we report 8 novel MYO5B mutations in 9 MVID patients of various etnic backgrounds, including compound heterozygous mutations. Our functional analysis indicate that MYO5B mutations can be correlated with an aberrant subcellular distribution of the myosin Vb protein and apical recycling endosomes which, together with the additional compound heterozygous mutations, significantly strengthen the link between MYO5B and MVID.