AUTHOR=Zelkowski Mateusz , Zelkowska Katarzyna , Conrad Udo , Hesse Susann , Lermontova Inna , Marzec Marek , Meister Armin , Houben Andreas , Schubert Veit 

TITLE=Arabidopsis NSE4 Proteins Act in Somatic Nuclei and Meiosis to Ensure Plant Viability and Fertility

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00774

DOI=10.3389/fpls.2019.00774

ISSN=1664-462X

ABSTRACT=<p>The SMC 5/6 complex together with cohesin and condensin is a member of the structural maintenance of chromosome (SMC) protein family. In non-plant organisms SMC5/6 is engaged in DNA repair, meiotic synapsis, genome organization and stability. In plants, the function of SMC5/6 is still enigmatic. Therefore, we analyzed the crucial δ-kleisin component NSE4 of the SMC5/6 complex in the model plant <italic>Arabidopsis thaliana</italic>. Two functional conserved <italic>Nse4</italic> paralogs (<italic>Nse4A</italic> and <italic>Nse4B</italic>) are present in <italic>A. thaliana</italic>, which may have evolved via gene subfunctionalization. Due to its high expression level, <italic>Nse4A</italic> seems to be the more essential gene, whereas <italic>Nse4B</italic> appears to be involved mainly in seed development. The morphological characterization of <italic>A. thaliana</italic> T-DNA mutants suggests that the NSE4 proteins are essential for plant growth and fertility. Detailed investigations in wild-type and the mutants based on live cell imaging of transgenic GFP lines, fluorescence <italic>in situ</italic> hybridization (FISH), immunolabeling and super-resolution microscopy suggest that NSE4A acts in several processes during plant development, such as mitosis, meiosis and chromatin organization of differentiated nuclei, and that NSE4A operates in a cell cycle-dependent manner. Differential response of NSE4A and NSE4B mutants after induced DNA double strand breaks (DSBs) suggests their involvement in DNA repair processes.</p>