Abstract
Mutant alleles of the microtubule-associated protein, MOR1, are useful for studying the essential role of microtubules in plant cell morphology. Compared to the rapid disruption of cortical microtubules, cell division was not obvious in the temperature-sensitive mor1-1 allele1. The more severe gemini1 alleles of MOR1, however, produce defective pollen, indicating a role for MOR1 in cell division2. Here we demonstrate that vegetative cells of mor1-1 have defective phragmoplasts and spindles. At restrictive temperature, mor1-1 spindles and phragmoplasts had significantly shorter microtubules and became abnormally organized. Subsequently, aberrant cell plates were produced. Double immunolabelling revealed that MOR1 protein was distributed along the full length of microtubules in all four microtubule arrays. At restrictive temperature, mor1 protein remained associated with the disorganized and short microtubules, suggesting that MOR1's loss of function in the mutant alleles is not caused by dissociation from microtubules.
1.Whittington et al.(2001)Nature,411
2.Twell et al.(2002)Nature Cell Biology,4
