Mechanism of Cytoplasmic Localization

褐藻Fucus的Quatrano 96-04672合子博士提供了一个模型系统来研究合子/细胞不对称的产生以及局部细胞质成分向所产生的子细胞的分配所涉及的基本机制。大的单细胞受精卵在培养中同步发育出一个极轴，可以通过施加梯度(如单边光)来实验定位。这些细胞提供了一个理想的系统来研究极轴是如何建立的，以及细胞如何定向地将细胞质物质运输到由细胞外载体定义的位置。Quatrano博士现在知道，将这些靶向囊泡分泌到细胞外基质(ECM)中是稳定外部载体建立的分子不对称性所必需的，并相信这也有证据表明，分泌到ECM中的物质可能会向细胞质发出信号，以启动极地生长和定向细胞分裂平面。靶向分泌的作用导致了Fucus合子ECM中存在的大分子的不对称性，现在提供了一个令人兴奋的范例来应用于其他极地细胞来研究发育过程中的细胞外位置信息。利用Fucus系统，他将寻求以下问题的答案：在发育中的Fucus胚胎中，负责特定转录本定位的是什么细胞线索和信使核糖核酸序列？在Fucus受精卵中，小的GTP结合蛋白和Septins在细胞极性的形成和细胞分裂的方向中起什么作用？在岩藻中建立极性的分子和过程与在高等植物、酵母、昆虫和脊椎动物中起作用的分子和过程有什么相似之处？

Dr. Quatrano 96-04672 Zygotes of the brown alga Fucus provide a model system to study the basic mechanisms involved in the generation of zygotic/cell asymmetry and the partitioning of localized cytoplasmic components to the resulting daughter cells. Large, single-celled zygotes synchronously develop a polar axis in culture that can be experimentally oriented by imposed gradients such as unilateral light. Such cells present an ideal system to study how a polar axis is established and how a cell directionally transports cytoplasmic material to a site defined by an extracellular vector. Dr. Quatrano now knows that secretion of these targeted vesicles into the extracellular matrix (ECM) is required to stabilize the molecular asymmetry established by the external vector, and believes that this also have evidence that secreted material into the ECM may signal information to the cytoplasm to initiate polar growth and to orient the plane of cell division. The role of targeted secretion, resulting in an asymmetry of the macromolecules present in the zygotic ECM of Fucus, now provides an exciting paradigm to apply to other polar cells for the study of extracellular positional information during development. Using the Fucus system he will pursue answers to the following questions: What are the cellular cues and sequences in MRNA that are responsible for the localization of specific transcripts in the developing Fucus embryo? What are the roles of small GTP-binding proteins and septins in the development of cell polarity and the orientation of cell division in the Fucus zygote? What are the similarities between the molecules and processes that establish polarity in Fucus and those operative in higher plants, yeast, insects, and vertebrates?