engleski

The MATH-BTB protein ZmMAB1 regulates spindle organization during germline development in maize

Meiosis represents a fundamental cell division process required for sexual plant reproduction in eukaryotes. Whereas in animals the product of meiosis are gametes, subsequent mitotic divisions of both male and female gametophyte development are needed for gamete formation in most plant species. Cytological studies gave an insight into gametophyte development in plants, but the knowledge about regulatory mechanisms underlying meiotic and mitotic cell cycle progression of developing gametophytes is still limited. Here, we report the identification of a maize gene encoding a protein with a MATH and a BTB domain (ZmMAB1) that displays a specific expression pattern during both male and female germline development. Silencing of ZmMAB1 leads to severe defects in chromosome segregation during meiosis I and short spindles in meiosis II causing insufficient separation and migration of nuclei as well as germline arrest. Transient expression studies of ZmMAB1 in tobacco BY-2 cells revealed a cell cycle dependent localization pattern inside and outside the nucleus. The interaction of ZmMAB1 with Cullin 3 suggests a function for ZmMAB1 as a substrate-specific adaptor protein in Cul3-based E3 ubiquitin ligase complexes, thereby providing further evidence for the importance of posttranslational regulation of both male and female germline development through the ubiquitin-proteasome pathway.

pollination biology and ecology; gametophyte; fertilization; imprinting; fruit; seed and stress

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