Genetically induced microtubule disruption in the mouse intestine impairs intracellular organization and transport

In most differentiated cells, microtubules reorganize into noncentrosomal arrays that are cell-type specific. In the columnar absorptive enterocytes of the intestine, microtubules form polarized apical-basal arrays that have been proposed to play multiple roles. However, in vivo testing of these hypotheses has been hampered by a lack of genetic tools to specifically perturb microtubules. Here we analyze mice in which microtubules are disrupted by conditional inducible expression of the microtubule-severing protein spastin. Spastin overexpression resulted in multiple cellular defects, including aberrations in nuclear and organelle positioning and deficient nutrient transport. However, cell shape, adhesion, and polarity remained intact, and mutant mice continued to thrive. Notably, the phenotypes of microtubule disruption are similar to those induced by microtubule disorganization upon loss of CAMSAP3/Nezha. These data demonstrate that enterocyte microtubules have important roles in organelle organization but are not essential for growth under homeostatic conditions.