QQT proteins colocalize with microtubules and are essential for early embryo development in Arabidopsis.
During Arabidopsis embryogenesis, the control of division between daughter cells is critical for pattern formation. Two embryo-defective (emb) mutant lines named quatre-quart (qqt) were characterized by forward and reverse genetics. The terminal arrest of qqt1 and qqt2 embryos was at the octant stage, just prior to the round of periclinal divisions that establishes the dermatogen stage . Homozygous embryos of a weaker allele of qqt1 were able to divide further, resulting in aberrant periclinal divisions. These phenotypic analyses support an essential role of the QQT proteins in the correct formation of the tangential divisions. That an important proportion of qqt1 embryos were arrested prior to the octant stage indicated a more general role in cell division. The analysis of QQT1 and QQT2 genes revealed that they belong to a small subgroup of the large family encoding ATP/GTP binding proteins, and are widely conserved among plants, vertebrates and Archaea. We showed that QQT1 and QQT2 proteins interact with each other in a yeast two-hybrid system, and that QQT1 and QQT2 tagged by distinct fluorescent probes colocalize with microtubules during mitosis, in agreement with their potential role in cell division and their mutant phenotype. We propose that QQT1 and QQT2 proteins participate in the organization of microtubules during cell division, and that this function is essential for the correct development of the early embryo.
Lahmy
Sylvie
S
Laboratoire Génome et Développement des Plantes, UMRCNRS 5096, Université de Perpignan, Avenue Paul Alduy, 66860 Perpignan-cedex, France.
Guilleminot
Jocelyne
J
Schmit
Anne-Catherine
AC
Pelletier
Georges
G
Chaboute
Marie-Edith
ME
Devic
Martine
M
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000196:embryology* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D001483:Base Sequence; D002455:Cell Division; D017931:DNA Primers; D017343:Genes, Plant; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D012639:Seeds / Q000254:growth & development*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D017931:DNA Primers