Three rice genes time chromosome splitting in pollen and egg formation
You H, Chen Y, Zhong W, Xiang K, Zhang J
Crispr
Rice sterility from failed pollen and egg formation limits seed set and yield, and knowing which genes control the timing of chromosome splitting gives breeders new handles for fertility and hybrid seed work.
When a cell divides, it has to split its chromosomes at exactly the right moment. Rice carries three copies of a gene that gives this go signal, and researchers used gene editing to weaken them in different degrees. Losing them all killed the pollen and egg cells, while partial weakening let ordinary growth continue but stopped the special divisions that make seeds possible.
Key Findings
Complete loss of all three CDC20 genes caused defects in gametophyte mitosis and bilateral gametophyte lethality (both male and female).
Hypomorphic alleles cdc20-triple-1 and -2 arrested at metaphase I with normal chromosome alignment but failed to remove the cohesin SCC3 from chromosome arms, while alleles -3 and -4 passed meiosis I and arrested at metaphase II with aberrant spindles and missegregation.
SGO1 stayed stuck at centromeres in cdc20-triple-1 even when sister chromatids separated abnormally, but unloaded normally in cdc20-triple-3, indicating that timely SGO1 removal depends on CDC20-mediated metaphase I-to-anaphase I transition.
chevron_right Technical Summary
Rice has three copies of a gene that acts like a starter pistol for chromosome separation during cell division. Knocking them out completely kills the pollen and egg cells, while partial loss disrupts only the specialized division that makes those cells, causing sterility.
Abstract Preview
Original paper
A CDC20 allelic series reveals stage-specific control of metaphase-to-anaphase transitions during mitosis and meiosis in rice.
The metaphase-to-anaphase transition is a critically controlled checkpoint essential for precise chromosome segregation. In yeast and animals, cell division cycle 20 (CDC20) serves as an essential ...
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