Regulation of stem cell differentiation during Drosophila oogenesis

果蝇卵子发生过程中干细胞分化的调控

• 批准号: 8898856
• 负责人: Prashanth Rangan
• 金额: $ 28.76万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT ALBANY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8898856
• 关键词: Address; Adult; Biological Models; Cell Cycle; Cell Differentiation process; Cell division; Cells; Cessation of life; Cis-Acting Sequence; Complex; Cytoplasmic Granules; DNA Polymerase II; Data; Daughter; Defect; Degenerative Disorder; Disease; Drosophila genus; Drosophila melanogaster; Embryo; Embryonic Development; Environment; Failure; Female; Gene Silencing; Genes; Genetic; Genetic Transcription; Germ Cells; Germ Lines; Goals; Health; Lead; Malignant Neoplasms; Mediating; Methods; Oocytes; Oogenesis; Organ; Ovary; Pathway interactions; Phase; Play; Positive Transcriptional Elongation Factor B; Process; RNA; RNA Interference; Regulation; Regulatory Pathway; Reporter; Research; Residual state; Role; Signal Transduction; Somatic Cell; Specific qualifier value; Staining method; Stains; Stem Cell Factor; Stem cells; System; Technology; Testing; Therapeutic; Therapeutic Uses; Trans-Activators; Transcription Elongation; Translational Regulation; Undifferentiated; Western Blotting; Work; base; cancer therapy; cell type; factor EF-P; gain of function; genome analysis; germline stem cells; loss of function; mutant; new therapeutic target; premature; prevent; response; self-renewal; stem cell differentiation; stem cell fate; tool

DESCRIPTION (provided by applicant): Loss of stem cell self-renewal results in failure to maintain organs and can lead to degenerative disorders. In contrast, loss of differentiation can lead to cancers. Thus, the ability to prevent premature differentiation in degenerative diseases, or to induce differentiation in case of cancer, will have tremendous therapeutic impact. Our long-term goal is to determine key regulatory pathways that control the transition from stem cell self-renewal to differentiation, using Drosophila germline stem cells (GSCs) as a model system. The germ cells are the ultimate stem cells as they are both totipotent as well as immortal. Thus, paradigms established in the germ line can be extended to other stem cell systems. Drosophila is a superior model system to study questions about stem cell self-renewal and differentiation because of the availability of mutants, markers, RNAi technology and targeted expression methods. In Drosophila embryogenesis, the conserved process of global transcriptional silencing, mediated by the gene polar granule component (pgc), plays a pivotal role in germ cell specification. In absence of pgc, germ cells show precocious transcription that result in the transcription of somatic genes leading to their death. During oogenesis, an oocyte fate is being specified from a GSC fate during the process of differentiation. We have discovered that during oogenesis, Pgc is transiently expressed in the differentiating daughter of the GSC and loss of pgc results in differentiation defects. We propose that during oogenesis, Pgc mediated transcriptional silencing acts to suppress the response to self-renewal signaling from the surrounding niche cells and promotes differentiation in the GSC daughter. To test this hypothesis we will (1) Determine how the transcriptional silencer, Pgc, promotes GSC differentiation; (2) Identify Pgc targets and the mechanism of action during GSC differentiation; (3) Investigate how pgc is regulated during oogenesis. Our work will establish a role for transient transcriptional silencing in reprogramming stem cell fate by demonstrating that Pgc in the GSC daughter is expressed in a cell cycle dependent manner and determining a requirement for Pgc to promote efficient differentiation. We favor the idea that transcriptional silencing is needed to "clear" residual stem cell factors, thereby reprogramming the GSC daughter prior to differentiation. Based on findings from this application, we posit that transcriptional silencing could be a potent target for increasing efficiency in deriving stem cells and also as a target in cancer treatment.

描述(由申请人提供)：干细胞自我更新的丧失会导致器官无法维持，并可能导致退行性疾病。相反，分化丧失可能导致癌症。因此，在退行性疾病中防止过早分化的能力，或者在癌症中诱导分化的能力，将对治疗产生巨大的影响。我们的长期目标是以果蝇生殖系干细胞(GSCs)为模型系统，确定控制干细胞自我更新向分化转变的关键调控途径。生殖细胞是终极干细胞，因为它们既是全能的，也是永生的。因此，在生殖系中建立的范例可以扩展到其他干细胞系统。由于突变体、标记物、RNAi技术和靶向表达方法的可获得性，果蝇是研究干细胞自我更新和分化问题的优越模型系统。在果蝇胚胎发育中，由基因极性颗粒组分(PGC)介导的整体转录沉默的保守过程在生殖细胞规范中起着关键作用。在没有PGC的情况下，生殖细胞表现出早熟转录，导致体细胞基因的转录导致它们的死亡。在卵子发生过程中，卵母细胞的命运是由分化过程中的GSC命运决定的。我们发现，在卵子发生过程中，PGC在GSC的分化子细胞中瞬时表达，而PGC的缺失会导致分化缺陷。我们认为，在卵子发生过程中，PGC介导的转录沉默抑制了对来自周围生态位细胞的自我更新信号的反应，并促进了GSC子代的分化。为了验证这一假说，我们将(1)确定转录沉默蛋白PGC是如何促进GSC分化的；(2)确定PGC靶标及其在GSC分化过程中的作用机制；(3)研究PGC在卵子发生过程中是如何调节的。我们的工作将为临时工建立一个角色 通过证明GSC子代中的PGC以细胞周期依赖的方式表达，并确定PGC促进有效分化的需求，在重新编程干细胞命运的过程中转录沉默。我们赞成这样一种观点，即转录沉默是 “清除”残留的干细胞因子，从而在分化前对GSC子代进行重新编程。基于这一应用的发现，我们假设转录沉默可能是提高干细胞提取效率的一个有效靶点，也可能是癌症治疗的一个靶点。