Genetic interaction between G2/M phase-specific transcription factor MYB3R4 and MAPKKK ANP3 for execution of cytokinesis in <i>Arabidopsis thaliana</i>
<div><p>Plant cells are surrounded by rigid cell walls, and hence, their division is associated with a plant-specific mode of cytokinesis in which the cell plate, a new cell wall, is generated and separates 2 daughter nuclei. The successful execution of cytokinesis requires the timely activation of multiple regulatory pathways, which include the AtNACK1/HINKEL kinesin-induced MAPK cascade and MYB3R1/4-mediated transcriptional activation of G2/M-specific genes. However, it remains unclear whether and how these pathways are functionally interconnected to each other. By analyzing enhancer mutations of <i>myb3r4</i>, here we found a close genetic interaction between the 2 pathways; a mutation in <i>ANP3</i>, which encodes MAPKKK (acting downstream of AtNACK1/HINKEL), strongly enhanced the defective cytokinesis observed in the <i>myb3r4</i> mutant. This interaction may not be due to the direct activation of MYB3R1/4 by the MAPK cascade; rather, possibly to the downstream targets of these 2 signaling pathways, acting in close proximity. Our results showed that MYB3R1/4 may positively affect cytokinesis via multiple pathways, one of which may act independently from the <i>KNOLLE</i>-dependent pathway defined previously, and affect the downstream events that may also be under the control of the AtNACK1/HINKEL-mediated MAPK cascade.</p></div
