CONTROL OF EARLY DEVELOPMENT IN C ELEGANS

每个多细胞生物体发育的关键过程是 不同细胞中不同发育命运的特化 早期胚胎 在秀丽隐杆线虫的胚胎中， 在许多其他物种的胚胎中，这一过程被认为是 主要由母体提供的因素控制， 在受精卵早期分裂时分裂。 除了 母亲因素，我们有新的证据表明，父亲提供的因素 也是正常早期发育所必需的。 我们建议将联合收割机 基因、分子和细胞生物学方法来识别关键的 母亲和父亲的因素，了解血统特异性因素是如何 差异分配到特定的细胞，并阐明何时以及如何 这些因子参与C. elegans 胚胎 我们发现了一种新的父系效应胚胎致死突变体，spe- 11，这表明精子贡献的因素是必需的， 合子发育正常。 两个令人兴奋的可能性是，特别- 11产物激活卵母细胞或为受精卵提供极性。 到 为了研究SPE-11产物的作用，我们将克隆SPE-11基因 分析并定位其基因产物，确定温度 突变体的敏感期，分离第二位点抑制子，并尝试 通过显微注射精子因子来拯救突变的受精卵。 母系 我们将重点关注的供应因素是生殖系所需的因素。 发展 P颗粒，由母源细胞质提供 在胚胎发育过程中分离到生殖系卵裂球的结构 早期分裂，是生殖系“决定因素”的极好候选者。 我们正在使用生化技术和我们收集的抗P颗粒 抗体来纯化和分析颗粒的组成;我们的 长期目标是评估它们在生殖系中的功能， 遗传学 同时，通过筛选母体效应不育的 无孙突变体，我们正在识别突变体的母亲缺陷， 生殖系发育的控制;其中一些可能会识别因素 决定了生殖细胞系 最后，我们继续分析 谱系特异性因素的分离机制。 我们有 已经证明，微丝（MF）发挥关键作用， 合子极性的产生和P颗粒向卵母细胞的分离 生殖谱系 我们将研究MF在分配中的作用 体细胞谱系特异性因素，我们将研究几个 MFs参与分离事件的具体机制， 例如肌动蛋白-肌球蛋白相互作用和细胞质流。

A crucial process in the development of every multicellular organism is the specification of different developmental fates in different cells of the early embryo. In embryos of the nematode Caenorhabditis elegans, as in embryos of many other species, this process is thought to be controlled mainly by maternally supplied factors that are differentially partitioned during the early divisions of the zygote. In addition to maternal factors, we have new evidence that paternally supplied factors also are required for normal early development. We propose to combine genetic, molecular, and cell biological approaches to identify crucial maternal and paternal factors, learn how lineage-specific factors are differentially partitioned to specific cells, and elucidate when and how such factors participate in cell-fate determination in C. elegans embryos. We have identified a novel paternal effect embryonic lethal mutant, spe- 11, that demonstrates that a sperm-contributed factor is required for normal zygote development. Two exciting possibilities are that the spe- 11 product activates the oocyte or provides polarity to the zygote. To investigate the role of the spe-11 product, we will clone the spe-11 gene and analyze and localize its gene product, define the temperature- sensitive period of the mutant, isolate second site suppressors, and try to rescue mutant zygotes by microinjecting sperm factors. The maternally supplied factors on which we will focus are those required for germ-line development. P granules, which are maternally supplied cytoplasmic structures that are segregated to the germ-line blastomeres during the early divisions, are excellent candidates for germ-line "determinants". We are using biochemcal techniques and our collection of anti-P-granule antibodies to purify and analyze the composition of the granules; our long-term goal is to assess their function in the germ line through genetics. Concurrently, by screening for maternal effect sterile of grand-childless mutants, we are identifying mutants defective in maternal control of germ-line development; some of these may identify the factors that determine the germ line. Finally, we are continuing our analysis of the mechanism of segregation of lineage-specific factors. We have already demonstrated that microfilaments (MFs) play a critical role in the generation of zygotic polarity and in segregating P granules to the germ lineage. We will investigate the role of MFs in partitioning somatic-lineage-specific factors, and we will investigate several specific mechanisms by which MFs could participate in segregation events, such as actin-myosin interactions and cytoplasmic streaming.