TY - JOUR TI - Arabidopsis monomeric G-proteins, markers of early and late events in cell differentiation AU - Bedhomme, Mariette AU - Mathieu, Chantal AU - Pulido, Amada AU - Henry, Yves AU - Bergounioux, Catherine T2 - The International Journal of Developmental Biology AB - In Schizosaccharomyces pombe, septum formation is intricately controlled by proteins which constitute the SIN (Septum Initiation Network) signalling cascade. The SIN ensures the coordination between mitotic exit and cytokinesis. Yeast spg1p is a core component of the SIN pathway and we have previously characterized the two orthologs of this G-protein in Arabidopsis thaliana (named AtSGP1 and 2). In this work, the cell and tissue expression of AtSGP genes during plant development has been analysed using AtSGP promoter::GUS fusions in stably transformed A. thaliana lines. AtSGP1 promoter activity was restricted to the quiescent centre, collumella cells, stomata guard cells and the stele while AtSGP2 promoter activity was detected in atrichoblasts, trichomes and pollen. The observed promoter activities are in accordance with publicly available pollen, stomata guard cell and root transcriptome data. Two-hybrid experiments previously evidenced an interaction between AtMAP3Kepsilon1 and AtSGP1. The AtMAP3Kepsilon1 promoter activity was detected in root apices, trichomes and ovule integuments. A genetic approach involving both markers of these specialized cells and mutant backgrounds was used to reinforce our hypothesis. It appears that, although highly conserved between plants and fungi, the spg1p G-protein has evolved in plants to perform a function different from the SIN pathway. Interestingly, cells expressing AtSGPs possessed limited or null mitotic activity. Our data suggests that AtSGP are crucial signalling components involved either in early cell fate specification, or in the final steps of cell differentiation. This is an interesting starting point for a wider study devoted to functional experiments designed to test these hypotheses. PY - 2009 DO - 10.1387/ijdb.072488mb VL - 53 IS - 1 SP - 177 EP - 185 J2 - Int. J. Dev. Biol. LA - en SN - 0214-6282 SN - 1696-3547 UR - https://ijdb.ehu.eus/article/072488mb Y2 - 2024/11/23/13:40:44 ER -