Department of Plant Biology, University of Georgia, Athens, GA 30602, USA; Department of Genetics, University of Georgia, Athens, GA 30602, USA.
Department of Genetics, University of Georgia, Athens, GA 30602, USA.
Cell. 2018 May 3;173(4):839-850.e18. doi: 10.1016/j.cell.2018.03.009. Epub 2018 Apr 5.
Maize abnormal chromosome 10 (Ab10) encodes a classic example of true meiotic drive that converts heterochromatic regions called knobs into motile neocentromeres that are preferentially transmitted to egg cells. Here, we identify a cluster of eight genes on Ab10, called the Kinesin driver (Kindr) complex, that are required for both neocentromere motility and preferential transmission. Two meiotic drive mutants that lack neocentromere activity proved to be kindr epimutants with increased DNA methylation across the entire gene cluster. RNAi of Kindr induced a third epimutant and corresponding loss of meiotic drive. Kinesin gliding assays and immunolocalization revealed that KINDR is a functional minus-end-directed kinesin that localizes specifically to knobs containing 180 bp repeats. Sequence comparisons suggest that Kindr diverged from a Kinesin-14A ancestor ∼12 mya and has driven the accumulation of > 500 Mb of knob repeats and affected the segregation of thousands of genes linked to knobs on all 10 chromosomes.
玉米异常染色体 10（Ab10）编码了一个经典的真正减数分裂驱动的例子，它将称为 knob 的异染色质区域转化为可移动的新着丝粒，这些新着丝粒优先传递到卵细胞中。在这里，我们在 Ab10 上鉴定了一个称为驱动蛋白（Kindr）复合物的八个基因簇，该复合物对于新着丝粒的运动和优先传递都是必需的。两个缺乏新着丝粒活性的减数分裂驱动突变体被证明是 kindr 外显子突变体，整个基因簇的 DNA 甲基化增加。Kindr 的 RNAi 诱导了第三个外显子突变体，并导致减数分裂驱动相应丢失。驱动蛋白滑行实验和免疫定位显示，KINDR 是一种功能性的负端定向驱动蛋白，特异性定位于含有 180 bp 重复序列的 knob 上。序列比较表明，Kindr 从约 1200 万年前的 Kinesin-14A 祖先分化而来，并导致了>500 Mb 的 knob 重复序列的积累，并影响了与 10 条染色体上的 knob 相连的数千个基因的分离。
