title: AtHaspin phosphorylates histone H3 at threonine 3 during mitosis and contributes to embryonic patterning in Arabidopsis.
abstract: Post-translational histone modifications regulate many aspects of chromosome activity. Threonine 3 of histone H3 is highly conserved, but the significance of its phosphorylation is unclear, and the identity of the corresponding kinase in plants is unknown. Therefore, we characterized the candidate kinase in Arabidopsis thaliana, called AtHaspin. Recombinant AtHaspin in vitro phosphorylates histone H3 at threonine 3. Reduction of H3 threonine 3 phosphorylation level and reduced chromatin condensation in interphase nuclei by AtHaspin RNAi supports the proposition that this kinase is involved in histone H3 phosphorylation in vivo in mitotic cells. In addition, we provide a developmental function for a Haspin kinase. At the whole plant level, altered expression of the kinase induced pleiotropic phenotypes with defects in floral organs and vascular tissue. It reduced fertility and modified adventitious shoot apical meristems that then gave rise to plants with multi-rosettes and multi-shoots. Haspin mutant embryos frequently showed alteration in division plane orientation that could be traced back to the earliest divisions of embryo development, thus Haspin contributes to embryonic patterning.
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstr. 3, 06466 Gatersleben, Germany.
authors.forename: Raheleh Karimi
authors.initials: RK
authors.lastname: Ashtiyani
authors.forename: Ali Mohammad Banaei
authors.initials: AM
authors.lastname: Moghaddam
authors.forename: Veit
authors.initials: V
authors.lastname: Schubert
authors.forename: Twan
authors.initials: T
authors.lastname: Rutten
authors.forename: Jörg
authors.initials: J
authors.lastname: Fuchs
authors.forename: Dmitri
authors.initials: D
authors.lastname: Demidov
authors.forename: Frank R
authors.initials: FR
authors.lastname: Blattner
authors.forename: Andreas
authors.initials: A
authors.lastname: Houben
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D006657:Histones / Q000378:metabolism*; D007399:Interphase; D008938:Mitosis; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D013912:Threonine / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D006657:Histones; D013912:Threonine; D017346:Protein Serine-Threonine Kinases