Miki Futaba, Okazaki Koei, Shimanuki Mizuki, Yamamoto Ayumu, Hiraoka Yasushi, Niwa Osami
Kazusa DNA Research Institute, Kisarazu 292-0812, Japan.
Mol Biol Cell. 2002 Mar;13(3):930-46. doi: 10.1091/mbc.01-11-0543.
A Schizosaccharomyces pombe spindle pole body (SPB) protein interacts in a two-hybrid system with Dlc1, which belongs to the 14-kDa Tctex-1 dynein light chain family. Green fluorescent protein-tagged Dlc1 accumulated at the SPB throughout the life cycle. During meiotic prophase, Dlc1 was present along astral microtubules and microtubule-anchoring sites on the cell cortex, reminiscent of the cytoplasmic dynein heavy chain Dhc1. In a dlc1-null mutant, Dhc1-dependent nuclear movement in meiotic prophase became irregular in its duration and direction. Dhc1 protein was displaced from the cortex anchors and the formation of microtubule bundle(s) that guide nuclear movement was impaired in the mutant. Meiotic recombination in the dlc1 mutant was reduced to levels similar to that in the dhc1 mutant. Dlc1 and Dhc1 also have roles in karyogamy and rDNA relocation during the sexual phase. Strains mutated in both the dlc1 and dhc1 loci displayed more severe defects in recombination, karyogamy, and sporulation than in either single mutant alone, suggesting that Dlc1 is involved in nuclear events that are independent of Dhc1. S. pombe contains a homolog of the 8-kDa dynein light chain, Dlc2. This class of dynein light chain, however, is not essential in either the vegetative or sexual phases.
粟酒裂殖酵母纺锤体极体（SPB）蛋白在双杂交系统中与Dlc1相互作用，Dlc1属于14 kDa的Tctex-1动力蛋白轻链家族。绿色荧光蛋白标记的Dlc1在整个生命周期中都在SPB处积累。在减数分裂前期，Dlc1沿着星体微管和细胞皮层上的微管锚定位点存在，这让人联想到细胞质动力蛋白重链Dhc1。在dlc1基因缺失的突变体中，减数分裂前期依赖Dhc1的核运动在持续时间和方向上变得不规则。Dhc1蛋白从皮层锚定位点移位，并且在突变体中引导核运动的微管束的形成受到损害。dlc1突变体中的减数分裂重组减少到与dhc1突变体相似的水平。Dlc1和Dhc1在有性生殖阶段的核融合和rDNA重定位中也发挥作用。在dlc1和dhc1基因座都发生突变的菌株在重组、核融合和孢子形成方面表现出比单独的任何一个单突变体更严重的缺陷，这表明Dlc1参与了独立于Dhc1的核事件。粟酒裂殖酵母含有8 kDa动力蛋白轻链的同源物Dlc2。然而，这类动力蛋白轻链在营养生长阶段或有性生殖阶段都不是必需的。
