Cellular and Molecular Events in Early Leech Development

早期水蛭发育中的细胞和分子事件

• 批准号: 0314718
• 负责人: David Weisblat
• 金额: $ 40万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0314718&HistoricalAwards=false
• 关键词: Cellular; Molecular; Events; Early; Leech

0314718WeisblatIntellectual merit: This is an Accomplishment-Based Renewal of a project supported by NSF since 1984. The research seeks to understand development at the cellular and molecular levels in leeches (phylum Annelida). Comparing development in various animals should contribute to understanding how body plans of modern animals evolved from those of ancestral species.Recent years have seen the reorganization of most animal phyla into three main clades, Deuterostomia, Ecdysozoa and Lophotrochozoa. Most invertebrate phyla, including Annelida, belong the latter group, but most of our understanding of development has come from Deuterostomia [vertebrates, sea urchins] or Ecdysozoa [insects, nematodes]. Work on the leech Helobdella make it a useful point of departure for comparisons with other annelids (oligochaetes and polychaetes), other lophotrochozoans (e.g. flatworms and mollusks) and the "model" systems. Helobdella is useful for studying development because its embryos are suited for cellular and molecular techniques. This proposal is to continue investigations of cell fate determination, combining reverse genetic approaches (injecting anti-sense morpholino oligonucleotides to knock down gene expression or mRNAs synthesized in vitro to ectopically express native genes, fluorescent proteins or dominant negative constructs) with embryological techniques already available for Helobdella. Specific topics include:1. Significance of the maternally inherited Hro-nos, a nanos-class gene in Helobdella . We propose to test the hypothesis that gradually declining levels of HRO-NOS protein, translated from maternally inherited transcripts, control the duration of blast cell (segmental founder cell) production in individual embryonic stem cells (teloblasts).2. The dynamics of early WNT and NOTCH signaling in Helobdella. Immunostaining for HRO-WNTA protein reveals a dynamic pattern during the 2-cell stage; HRO-WNTA signaling seems to regulate cell-cell adhesion following the first cell division. In situ staining for Hro-notch transcripts shows a similar pattern, but time shifted about 30 minutes ahead of the HRO-WNTA pattern. We propose to test the hypothesis that Notch and Wnt signaling pathways interact in the 2-cell stage, to investigate the mechanisms by which this interaction is achieved.Broader impacts: 1) The PI remains committed to expanding the national pool of scientific talent by recruiting and training women and members of underrepresented groups. Currently, the lab group consists of 1 assistant researcher (woman), 5 graduate students (3 women, including 1 of Mexican/native American origins) and 2 undergraduates (both of Filipino origin). One of the current undergrads, joined the lab via the "Junior Transfer Consortium", a program to identify, recruit and mentor science students who transfer to Berkeley with junior status from community colleges. A previous undergrad and postbac researcher (African-American male) from the PI's lab matriculated at UCSF medical school in the summer of 2002. 2) The PI also works to enhance the undergraduate experience at this large, research university by evaluating applicants for various research programs, and by participating in various faculty-undergrad forums. 3) The PI is active in promoting scientific goodwill and collaborations between the USA and developing nations. To this end, he has helped to organize and teach intensive and interactive lab and lecture courses in development and neurodevelopment, for students at the graduate level and beyond in Mexico, India and Brazil.

0314718Weisblat 智力价值：这是自 1984 年以来 NSF 支持的一个项目的基于成就的更新。该研究旨在了解水蛭（环节动物门）细胞和分子水平的发育。比较各种动物的发育应该有助于了解现代动物的身体结构是如何从祖先物种进化而来的。近年来，大多数动物门已重组为三个主要分支：后口动物门、蜕皮动物门和冠轮动物门。 大多数无脊椎动物门，包括环节动物门，都属于后一类，但我们对发育的大部分了解都来自后口动物门（脊椎动物、海胆）或蜕皮动物门（昆虫、线虫）。对水蛭 Helobdella 的研究使其成为与其他环节动物（寡毛类和多毛类）、其他冠轮动物（例如扁形虫和软体动物）和“模型”系统进行比较的有用出发点。 Helobdella 对于研究发育很有用，因为它的胚胎适合细胞和分子技术。该提案旨在继续研究细胞命运决定，将反向遗传方法（注射反义吗啉寡核苷酸来敲低基因表达或体外合成的mRNA以异位表达天然基因、荧光蛋白或显性失活结构）与已经可用于Helobdella的胚胎学技术相结合。 具体主题包括： 1．母系遗传的 Hro-nos（Helobdella 中的 nanos 类基因）的意义。 我们建议检验以下假设：从母系遗传转录本翻译而来的 HRO-NOS 蛋白水平逐渐下降，控制个体胚胎干细胞（端粒细胞）中母细胞（节段性始祖细胞）产生的持续时间。2． Helobdella 早期 WNT 和 NOTCH 信号传导的动态。 HRO-WNTA 蛋白的免疫染色揭示了 2 细胞阶段的动态模式； HRO-WNTA 信号传导似乎在第一次细胞分裂后调节细胞间粘附。 Hro-notch 转录本的原位染色显示出类似的模式，但时间比 HRO-WNTA 模式提前约 30 分钟。 我们建议测试 Notch 和 Wnt 信号通路在 2 细胞阶段相互作用的假设，以研究实现这种相互作用的机制。更广泛的影响：1) PI 仍然致力于通过招募和培训女性和代表性不足群体成员来扩大国家科学人才库。目前，实验室团队由 1 名助理研究员（女性）、5 名研究生（3 名女性，其中 1 名墨西哥/美洲原住民）和 2 名本科生（均为菲律宾裔）组成。 目前的一名本科生通过“初级转学联盟”加入了该实验室，该项目旨在识别、招募和指导从社区学院以初级身份转学到伯克利的理科学生。 PI 实验室的一名本科生和研究生研究员（非裔美国男性）于 2002 年夏天被加州大学旧金山分校医学院录取。2) PI 还致力于通过评估各种研究项目的申请者以及参加各种教师与本科生论坛来增强这所大型研究型大学的本科生体验。 3) PI 积极促进美国与发展中国家之间的科学友好和合作。 为此，他帮助墨西哥、印度和巴西的研究生及其他学生组织和教授发育和神经发育方面的强化、互动实验室和讲座课程。