Mutant Name: mor1

Gene Name MOR1
Protein Name microtubule organization protein 1
Mutagen EMS
Category forward genetics
Organism Arabidopsis thaliana
Ecotype Col
Donor
General Description 1. Mutants displayed temperature-sensitive cortical microcubule shortening and disorganization,and consequent morphological defects, including a left-handed twist of organs,isotropic cell expansion and impaired root hair polarity.
2.The transverse orientation of cellulose microfibrils remain unchanged and cellulose synthesis is not reduced at the restrictive temperature in the mutants.
3. In the mor1-1 mutant allele, a cytosine-to-thymine base change substitutes the amino acid leucine at position 174 with phenylalanine, whereas in mor1-2, a guanine-to-adenine change replaces the glutamic acid at position 195 with lysine.
4.The mor1-1 rsw1-1 Double Mutant Phenotype Is Additive.
Organ Specificity 1.MOR1 localizes to the spindle and to the phragmoplast.
2.Immunoblotting and analyses by polymerase chain reaction with reverse transcription (RT-PCR) showed that MOR1 is expressed in all of the vegetative and reproductive tissues.
Impact on Wall 1. Mor1-1 roots twist and swell without the Loss of transverse microfibril orientation.
2.Complete depolymerization of microtubules with oryzalin does not impair parallel cellulose microfibril orientation.
3.Cellulose Content is normal in mor1-1 mutants at the restrictive temperature.
Impact on Sugar Composition Cellulose content is normal in the mutants.
Reference 1.Sugimoto K, Himmelspach R, Williamson RE, Wasteneys GO. Mutation or drug-dependent microtubule disruption causes radial swelling without altering parallel cellulose microfibril deposition in Arabidopsis root cells. Plant Cell. 2003 Jun;15(6):1414-29. Erratum in: Plant Cell. 2003 Aug;15(8):1945.

2.Twell D, Park SK, Hawkins TJ, Schubert D, Schmidt R, Smertenko A, Hussey PJ. MOR1/GEM1 has an essential role in the plant-specific cytokinetic phragmoplast. Nat Cell Biol. 2002 Sep;4(9):711-4.

3.Whittington AT, Vugrek O, Wei KJ, Hasenbein NG, Sugimoto K, Rashbrooke MC, Wasteneys GO. MOR1 is essential for organizing cortical microtubules in plants. Nature. 2001 May 31;411(6837):610-3.