AUTHOR=Binder Andreas , Parniske Martin 

TITLE=Analysis of the Lotus japonicus nuclear pore NUP107-160 subcomplex reveals pronounced structural plasticity and functional redundancy

JOURNAL=Frontiers in Plant Science

VOLUME=4

YEAR=2014

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2013.00552

DOI=10.3389/fpls.2013.00552

ISSN=1664-462X

ABSTRACT=<p>Mutations in the <italic>Lotus japonicus</italic> nucleoporin genes, <italic>NUP85, NUP133</italic>, and <italic>NENA (SEH1)</italic>, lead to defects in plant-microbe symbiotic signaling. The homologous proteins in yeast and vertebrates are part of the conserved NUP84/NUP107-160 subcomplex, which is an essential component of the nuclear pore scaffold and has a pivotal role in nuclear pore complex (NPC) assembly. Loss and down-regulation of NUP84/NUP107-160 members has previously been correlated with a variety of growth and molecular defects, however, in <italic>L. japonicus</italic> only surprisingly specific phenotypes have been reported. We investigated whether Lotus <italic>nup85, nup133</italic>, and <italic>nena</italic> mutants exhibit general defects in NPC composition and distribution. Whole mount immunolocalization confirmed a typical nucleoporin-like localization for NUP133, which was unchanged in the <italic>nup85-1</italic> mutant. Severe NPC clustering and aberrations in the nuclear envelope have been reported for <italic>Saccharomyces cerevisiae nup85</italic> and <italic>nup133</italic> mutants. However, upon transmission electron microscopy analysis of <italic>L. japonicus nup85</italic>, <italic>nup133</italic> and <italic>nena</italic>, we detected only a slight reduction in the average distances between neighboring NPCs in <italic>nup133</italic>. Using quantitative immunodetection on protein-blots we observed that loss of individual nucleoporins affected the protein levels of other NUP107–160 complex members. Unlike the single mutants, <italic>nup85/nup133</italic> double mutants exhibited severe temperature dependent growth and developmental defects, suggesting that the loss of more than one NUP107–160 member affects basal functions of the NPC.</p>