Augmin’s Role in Microtubule Generation in Plants

Abstract

During mitosis and meiosis, microtubules (MTs) form bipolar spindles that facilitate chromosome segregation. In animals, spindle MTs have historically been thought of as originating from the centrosomes, but MTs also nucleate from other MTs and near chromatin (Goshima and Kimura, 2010). Flowering plants do not contain centrosomes, but it is becoming clear that cell division in plants and animals is more similar than previously thought (Lloyd and Chan, 2006). The augmin complex binds spindle MTs as well as the g-tubulin ring complex (g-TuRC) and is important for spindle MT generation without centrosome involvement. Augmin was discovered in Drosophila melanogaster, but a homolog of augmin subunit3 (AUG3) was recently shown to be needed for Arabidopsis thaliana spindle and phragmoplast formation (Ho et al., 2011). Thus, augmin’s role in spindle formation may be conserved, consistent with the generic similarities between plant and animal cell division.