The zinc finger protein DCM1 is required for male meiotic cytokinesis by preserving callose in rice.

Chao Zhang,Yihua Zhou,Zhukuan Cheng,Wenqing Shi,Dongmei Zhang,Yi Shen,Yafei Li,Ding Tang,Guijie Du,Guohua Liang,Yingxiang Wang

doi:10.1371/journal.pgen.1007769

Abstract

Meiotic cytokinesis influences the fertility and ploidy of gametes. However, limited information is available on the genetic control of meiotic cytokinesis in plants. Here, we identified a rice mutant with low male fertility, defective callose in meiosis 1 (dcm1). The pollen grains of dcm1 are proved to be defective in exine formation. Meiotic cytokinesis is disrupted in dcm1, resulting in disordered spindle orientation during meiosis II and formation of pollen grains with varied size and DNA content. We demonstrated that meiotic cytokinesis defect in dcm1 is caused by prematurely dissolution of callosic plates. Furthermore, peripheral callose surrounding the dcm1 pollen mother cells (PMCs) also disappeared untimely around pachytene. The DCM1 protein contains five tandem CCCH motifs and interacts with nuclear poly (A) binding proteins (PABNs) in nuclear speckles. The expression profiles of genes related to callose synthesis and degradation are significantly modified in dcm1. Together, we propose that DCM1 plays an essential role in male meiotic cytokinesis by preserving callose from prematurely dissolution in rice.

Highlights

Cytokinesis is the process by which the two daughter nuclei resulting from nuclear division are physically separated by the establishment of a cell plate and/or cell wall
We identified a novel CCCH-tandem zinc finger protein DCM1 that prevent the premature dissolution of callose both around the pollen mother cells (PMCs) and at the dividing site
The resulting normal seed setting rate indicated that female fertility was not affected in dcm1 (S1 Table)

Summary

Introduction

Cytokinesis is the process by which the two daughter nuclei resulting from nuclear division are physically separated by the establishment of a cell plate and/or cell wall. In animal and yeast dividing cells, an actomyosin ring contracts centripetally to separate the daughter cells [1]. Meiosis is a specialized type of cell division consisting of one round of DNA replication and two rounds of nuclear division [4]. Two different types of cell plate formation, namely successive and simultaneous cytokinesis, are documented. Each caryokinesis is directly followed by a cytokinetic event in successive cytokinesis (typically in monocots), while the simultaneous cytokinesis occurs only when both nuclear division are finalized (typically in dicots) [5]

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