Genetic interaction between G2/M phase-specific transcription factor MYB3R4 and MAPKKK ANP3 for execution of cytokinesis inArabidopsis thaliana

Abstract

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 myb3r4, here we found a close genetic interaction between the 2 pathways; a mutation in ANP3, which encodes MAPKKK (acting downstream of AtNACK1/HINKEL), strongly enhanced the defective cytokinesis observed in the myb3r4 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 KNOLLE-dependent pathway defined previously, and affect the downstream events that may also be under the control of the AtNACK1/HINKEL-mediated MAPK cascade.Unlike animals, plants typically have a rigid cell wall outside of each cell, which provides mechanical strength that sustains their shape and growth. Because of the presence of the cell wall, plants have evolved a unique mode of cytokinesis, which accompanies the generation of a new cell wall, called the cell plate. During cell division, a microtubule-based structure, the phragmoplast, appears between 2 separating daughter nuclei and fulfills functions that are essential for the accumulation and fusion of Golgi-derived vesicles at the equatorial region.1,2 The molecular mechanisms underlying the formation of the cell plate are largely unknown; however, recent genetic studies have revealed components of signaling pathways that are essential for the execution of cytokinesis in Arabidopsis thaliana. 2,3

Jasmonates, gibberellins, and powdery mildew modify cell cycle progression and evoke differential spatiotemporal responses along the barley leaf

“…(2008 , 2012 ), included the following: Cyclin A3 ( CYCA3 , HORVU.MOREX.r2.5HG0363660 ; a checkpoint regulator of S, S/G2 transition; Gendreau et al ., 2012 ; Qi and Zhang, 2020 ); Cyclin B1 ( CYCB1 , HORVU.MOREX.r2.3HG0246040 ; a checkpoint regulator at the G2/M transition; Dewitte et al , 2003 ); Cyclin-Dependent Kinase A1 (CDKA1 , HORVU.MOREX.r2.6HG0457700 ; known to be constitutively expressed throughout the cell cycle and acts as a positive regulator of cell proliferation; Iwakawa et al ., 2006 ; Gendreau et al ., 2012 ), Cyclin-Dependent Kinase B1 ( CDKB1 , HORVU.MOREX.r2.7HG0565000 ; functions during G2/M and the S/G2 phase of the cell cycle; Dewitte et al , 2003 ; Gendreau et al ., 2012 ); Cyclin-Dependent Kinase D1 ( CDKD1 , HORVU.MOREX.r2.7HG0565000 ; its expression increases from G1 to S phase, and it mediates cell-cycle progression through the activation of CDK s such as CDKA1 and CDKB1 ; Gendreau et al ., 2012 ; Gutierrez et al , 2009 ; Takatsuka et al ., 2015 ); and the nuclear kinase WEE1 ( HORVU.MOREX.r2.6HG0461230 ; a negative regulator of the G2/M phase that inhibits the activities of CDKA and CDKB ; De Schutter et al , 2007 ; Qi and Zhang, 2020 ). The MYB3R4 transcription factor ( HORVU.MOREX.r2.3HG0206530 ) has not been formally identified as a cell-cycle marker, but it controls the expression of G2/M phase-specific genes and maintains diploidy ( Saito et al , 2015 ; Haga et al , 2007 , 2011 ). For a schematic depiction of the known roles of these genes in the cell cycle, see Fig.…”

Integrative analysis of physiology, biochemistry and transcriptome reveals the mechanism of leaf size formation in Chinese cabbage (Brassica rapa L. ssp. pekinensis)

“…In the G2/M phase, AtMYB3R1 and AtMYB3R4 active the CYCA2, CYCB1 and CYCB2 genes by recognizing and combing with MSA element ( Nomoto et al., 2022 ). Furthermore, MYB3R1 and MYB3R4 positively regulate cytokinesis by activating Knolle transcription ( Saito et al., 2015 ). In addition, AtMYB88 encode closely related and atypical two-MYB-repeat proteins, which, when mutated, result in excess divisions of stomata in contact ( Xie et al., 2010 ).…”

Integrative analysis of transcriptome and miRNAome reveals molecular mechanisms regulating pericarp thickness in sweet corn during kernel development

“…The MAPK cascade pathway regulates phragmoplast dynamics during cytokinesis in plants ( Nishihama et al, 2001 ; Soyano et al, 2003 ). The timely activation of multiple regulatory pathways, including the AtNACK1/HINKEL kinesin-induced MAPK cascade, was essential to cytokinesis ( Takahashi et al, 2010 ; Saito et al, 2015 ). Crosstalk has been found between the MAPK cascade and the phytohormone signaling pathway.…”