Myosin-1a is critical for normal brush border structure and composition.
To develop our understanding of myosin-1a function in vivo, we have created a mouse line null for the myosin-1a gene. Myosin-1a knockout mice demonstrate no overt phenotypes at the whole animal level but exhibit significant perturbations and signs of stress at the cellular level. Among these are defects in microvillar membrane morphology, distinct changes in brush-border organization, loss of numerous cytoskeletal and membrane components from the brush border, and redistribution of intermediate filament proteins into the brush border. We also observed significant ectopic recruitment of another short-tailed class I motor, myosin-1c, into the brush border of knockout enterocytes. This latter finding, a clear demonstration of functional redundancy among vertebrate myosins-I, may account for the lack of a whole animal phenotype. Nevertheless, these results indicate that myosin-1a is a critical multifunctional component of the enterocyte, required for maintaining the normal composition and highly ordered structure of the brush border.
Tyska
Matthew J
MJ
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA. matthew.tyska@vanderbilt.edu
Mackey
Andrew T
AT
Huang
Jian-Dong
JD
Copeland
Neil G
NG
Jenkins
Nancy A
NA
Mooseker
Mark S
MS
D000818:Animals; D003106:Colon / Q000378:metabolism / Q000648:ultrastructure; D004386:Duodenum / Q000378:metabolism / Q000648:ultrastructure; D020895:Enterocytes / Q000378:metabolism* / Q000648:ultrastructure*; D007082:Ileum / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008871:Microvilli / Q000378:metabolism* / Q000648:ultrastructure; D018995:Myosin Heavy Chains / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype
C491827:Myo1a protein, mouse; D018995:Myosin Heavy Chains