RT Journal Article SR Electronic T1 The Arabidopsis lue1 mutant defines a katanin p60 ortholog involved in hormonal control of microtubule orientation during cell growth JF Journal of Cell Science JO J. Cell Sci. FD The Company of Biologists Ltd SP 791 OP 801 DO 10.1242/jcs.00274 VO 116 IS 5 A1 Bouquin, Thomas A1 Mattsson, Ole A1 Næsted, Henrik A1 Foster, Randy A1 Mundy, John YR 2003 UL http://jcs.biologists.org/content/116/5/791.abstract AB The lue1 mutant was previously isolated in a bio-imaging screen for Arabidopsis mutants exhibiting inappropriate regulation of an AtGA20ox1 promoter-luciferase reporter fusion. Here we show that lue1 is allelic to fra2, bot1 and erh3, and encodes a truncated katanin-like microtubule-severing protein (AtKSS). Complementation of lue1 with the wild-type AtKSS gene restored both wild-type stature and luciferase reporter levels. Hormonal responses of lue1 to ethylene and gibberellins revealed inappropriate cortical microtubule reorientation during cell growth. Moreover, a fusion between the AtKSS protein and GFP decorated cortical microtubules. A yeast two-hybrid screen with AtKSS as the bait identified proteins related to those involved in microtubule processing, including a katanin p80 subunit and a kinesin ortholog. These results indicate that AtKSS is involved in microtubule dynamics in response to plant hormones.