Loss-of-function of MYO5B is the main cause of microvillus inclusion disease: 15 novel mutations and a CaCo-2 RNAi cell model
Open Access
- 25 February 2010
- journal article
- research article
- Published by Hindawi Limited in Human Mutation
- Vol. 31 (5), 544-551
- https://doi.org/10.1002/humu.21224
Abstract
Autosomal recessive microvillus inclusion disease (MVID) is characterized by an intractable diarrhea starting within the first few weeks of life. The hallmarks of MVID are a lack of microvilli on the surface of villous enterocytes, occurrence of intracellular vacuoles lined by microvilli (microvillus inclusions), and the cytoplasmic accumulation of periodic acid‐Schiff (PAS)‐positive vesicles in enterocytes. Recently, we identified mutations in MYO5B, encoding the unconventional type Vb myosin motor protein, in a first cohort of nine MVID patients. In this study, we identified 15 novel nonsense and missense mutations in MYO5B in 11 unrelated MVID patients. Fluorescence microscopy, Western blotting, and electron microscopy were applied to analyze the effects of MYO5B siRNA knock‐down in polarized, brush border possessing CaCo‐2 cells. Loss of surface microvilli, increased formation of microvillus inclusions, and subapical enrichment of PAS‐positive endomembrane compartments were induced in polarized, filter‐grown CaCo‐2 cells, following MYO5B knock‐down. Our data indicate that MYO5B mutations are a major cause of microvillus inclusion disease and that MYO5B knock‐down recapitulates most of the cellular phenotype in vitro, thus independently showing loss of MYO5B function as the cause of microvillus inclusion disease. Hum Mutat 31:1–8, 2010.This publication has 30 references indexed in Scilit:
- Navajo microvillous inclusion disease is due to a mutation inMYO5BAmerican Journal of Medical Genetics Part A, 2008
- Microvillous Inclusion Disease: Ultrastructural VariabilityUltrastructural Pathology, 2007
- CD10The American Journal of Surgical Pathology, 2002
- Fusion pore expansion is a slow, discontinuous, and Ca2+-dependent process regulating secretion from alveolar type II cellsThe Journal of cell biology, 2001
- Cryopreparation Provides New Insight into the Effects of Brefeldin A on the Structure of the HepG2 Golgi ApparatusJournal of Structural Biology, 2000
- Microvillus Inclusion Disease: A Genetic Defect Affecting Apical Membrane Protein Traffic in Intestinal EpitheliumTraffic, 2000
- Subcellular fractionation of polarized epithelial cells and identification of organelle‐specific proteins by two‐dimensional gel electrophoresisElectrophoresis, 1997
- In migrating fibroblasts, recycling receptors are concentrated in narrow tubules in the pericentriolar area, and then routed to the plasma membrane of the leading lamella.The Journal of cell biology, 1994
- Role of microtubules in polarized delivery of apical membrane proteins to the brush border of the intestinal epithelium.The Journal of cell biology, 1989
- Microvillus Inclusion Disease: An Inherited Defect of Brush-Border Assembly and DifferentiationThe New England Journal of Medicine, 1989