TANGLED1: A microtubule binding protein required for the spatial control of cytokinesis in maize

Spatial control of cytokinesis in plant cells depends on guidance of the cy tokinetic apparatus, the phragmoplast, to a cortical "division site" establ ished before mitosis. Previously, we showed that the Tangled1 (Tan1) gene o f maize is required for this process during maize leaf development (Cleary, A.L., and L.G. Smith. 1998. Plant Cell. 10:1875-1888.). Here, we show that the Tan1 gene is expressed in dividing cells and encodes a highly basic pr otein that can directly bind to microtubules(MTs). Moreover, proteins recog nized by anti-TAN1 antibodies are preferentially associated with the MT-con taining cytoskeletal structures that are misoriented in dividing cells of t an1 mutants. These results suggest that TAN1 protein participates in the or ientation of cytoskeletal structures in dividing cells through an associati on with MTs.