TETRASPORE encodes a kinesin required for male meiotic cytokinesis in Arabidopsis

Abstract

SummaryA key step in pollen formation is the segregation of the products of male meiosis into a tetrad of microspores, each of which develops into a pollen grain. Separation of microspores does not occur in tetraspore (tes) mutants of Arabidopsis thaliana, owing to the failure of male meiotic cytokinesis. tes mutants thus generate large`tetraspores' containing all the products of a single meiosis. Here, we report the positional cloning of the TES locus and details of the role played by the TES product in male cytokinesis. The predicted TES protein includes an N-terminal domain homologous to kinesin motors and a C-terminus with little similarity to other proteins except for a small number of plant kinesins. These include the Arabidopsis HINKEL protein and NACK1 and two from tobacco (Nishihama et al., 2002), which are involved in microtubule organization during mitotic cytokinesis. Immunocytochemistry shows that the characteristic radial arrays of microtubules associated with male meiotic cytokinesis fail to form in tes mutants. The TES protein therefore is likely to function as a microtubule-associated motor, playing a part either in the formation of the radial arrays that establish spore domains following meiosis, or in maintaining their stability.

Pollen and Stigma Structure and Function: The Role of Diversity in Pollination

“…Other Arabidopsis mutations have a more severe fusion defect. Pollen from tetraspore/stud (tes/ stud) mutants fail to undergo cytokinesis, resulting in the release of a giant pollen grain that contains four vegetative nuclei and up to eight sperm (Hulskamp et al, 1997;Spielman et al, 1997;Yang et al, 2003). Although these mutations have led to interesting insights, there are likely additional genes to be found; screens for tes or quartet phenotypes were not performed to saturation.…”

TheArabidopsis thalianaHomolog of YeastBRE1Has a Function in Cell Cycle Regulation during Early Leaf and Root Growth

“…Of the 61 Arabidopsis genes encoding kinesins (Lee and Liu, 2004), 21 with a clear link to the cell division process were downregulated in hub1-1, among which are HINKEL/NACK1 and TETRASPORE/NACK2, KNOLLE, and MAP/PLEIADE. The hinkel, tetraspore, knolle, and pleiade knockout mutants are known to be defective in the cell plate formation during cytokinesis, leading to abnormal cells with often large nuclei (Mü ller et al, 2002;Strompen et al, 2002;Yang et al, 2003). The absence of a defect in root apical meristem organization in hub1-1 is another argument for the mutation most probably affecting the entry into mitosis rather than the phragmoplast or cell plate formation itself.…”

Cytoskeletal Motors in Arabidopsis. Sixty-One Kinesins and Seventeen Myosins

“…The AtTES/NACK2 kinesin, similar to AtNACK1/ HIK, however, is not required for vegetative cytokinesis (Yang et al, 2003). Instead, it is required for the establishment of the radial microtubule array prior to the meiotic cytokinesis, and thus is essential for tetrad formation during male gametogenesis (Yang et al, 2003).…”

“…Instead, it is required for the establishment of the radial microtubule array prior to the meiotic cytokinesis, and thus is essential for tetrad formation during male gametogenesis (Yang et al, 2003). Whether AtTES/NACK2 interacts with ANP kinases awaits further characterization.…”