Functional consequences of evolutionary innovation in histone repertoires

组蛋白库进化创新的功能后果

基本信息

批准号：
10644921
负责人：
Pravrutha Raman
金额：
$ 12.5万
依托单位：
FRED HUTCHINSON CANCER CENTER
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10644921
关键词：
Affect Biological Biological Assay Biological Process Biology Birth Cell physiology Cells Chromatin DNA DNA Damage DNA Packaging DNA Repair DNA Repair Gene Defect Development Disease Drosophila genome Drosophila genus Engineering Eukaryota Event Evolution Fertility Foundations Frequencies Future Gene Duplication Gene Expression Gene Expression Regulation Gene Fusion Genes Genetic Genetic Transcription Genome Genomics Growth Heterochromatin Histone Fold Histone H2A Histones Learning Length Link Location Malignant Neoplasms Mediating Meiosis Mitosis Molecular Evolution Mutate Mutation N-terminal Organism Partner in relationship Phenotype Phylogenetic Analysis Play Process Protein Family Proteins Recording of previous events Recurrence Regulation Research Role Saccharomyces cerevisiae Saccharomycetales Specificity Tail Testing Training Variant Work Yeasts fitness flexibility fly fungus gene repression genomic locus improved in vivo innovation insight model organism mutant novel pressure prevent programs response skills tool

项目摘要

PROJECT SUMMARY Histone proteins package DNA into chromatin and regulate all DNA-templated biological processes in eukaryotes. Consistent with their essential function, mutations or misregulation of histones result in many diseases. While core histones primarily function in genome packaging, histone variants can replace canonical histones at unique genomic locations for specialized roles such as DNA damage response (DDR) or gene expression. Despite their essential functions, histone repertoires have undergone distinct lineage-specific changes. Such evolutionary novelty via gene fusions, duplications or sequence divergence is unexpected in conserved protein families and suggestive of an adaptive advantage for sequence innovation. This proposal will use evolutionary innovations in eukaryotic histone H2A repertoires to investigate the causes and consequences of evolutionary turnover of histone proteins. The most common eukaryotic H2A repertoire is made up of core histone H2A, and histone variants H2A.X and H2A.Z that are involved in DDR and gene regulation, respectively. However, two evolutionary shifts, both likely selectively advantageous, have occurred in yeast and Drosophila H2A repertoires. In yeast, H2A.X, entirely replaced canonical H2A, likely improving DDR and affecting processes like meiosis that depend on DDR. In Drosophila, H2A.X fused with H2A.Z giving rise to a unique H2Av variant. This fusion enriches DDR at heterochromatin which potentially restricts DDR- based transposition events to gene poor regions. To identify functional consequences of these evolutionary innovations, the applicant will re-engineer the ancestral eukaryotic H2A repertoire in yeast and flies. Specifically in S. cerevisiae, the applicant will engineer a core H2A and two variants H2A.X and H2A.Z, preventing H2A.X from being the core histone (Aim 1). In D. melanogaster, the fusion histone H2Av will be separated into H2A.X and H2A.Z uncoupling DDR and gene regulation functions (Aim 2). Changes to organismal chromatin packaging, and relevant biological functions including DNA repair, meiosis, fertility, and transposition will be interrogated. In Aim 3, the applicant will apply tools learnt in Aims 1 and 2 to study divergence of eukaryotic core H2A. Histones have tail sequences which are heavily post-translationally modified and play crucial roles for higher order chromatin packaging and protein interactions. The high sequence divergence across eukaryotic histone tails suggests that tails could facilitate unique lineage-specific functions. By engineering different tail sequences in yeast and flies, Aim 3 will reveal changes to chromatin packaging, and changes to processes such as mating, and quiescence in yeast, and fertility and development in flies. To launch this work, the applicant requires training in genetics, genomics, and phenotypic assays in two model organisms, yeast and flies. By leveraging, her expertise in evolutionary analyses and the power of well-established tools in yeast and flies simultaneously, in the future the applicant will study the biological basis and consequences of histone innovation including her own previous discoveries and co-evolving mechanisms.

项目概要组蛋白将 DNA 包装到染色质中并调节所有以 DNA 为模板的生物过程真核生物。与其基本功能一致，组蛋白的突变或失调会导致许多疾病。虽然核心组蛋白主要在基因组包装中发挥作用，但组蛋白变体可以取代经典组蛋白组蛋白位于独特的基因组位置，具有特殊作用，例如 DNA 损伤反应 (DDR) 或基因表达。尽管具有基本功能，但组蛋白库已经经历了明显的谱系特异性变化。这种通过基因融合、重复或序列分歧而产生的进化新颖性在人类中是出乎意料的。保守的蛋白质家族并暗示序列创新的适应性优势。这个提议将利用真核组蛋白 H2A 库的进化创新来研究其原因和组蛋白进化更新的后果。最常见的真核 H2A 库是由核心组蛋白 H2A 以及参与 DDR 和基因的组蛋白变体 H2A.X 和 H2A.Z 组成分别进行监管。然而，已经发生了两种进化转变，两者都可能具有选择性优势在酵母和果蝇 H2A 库中。在酵母中，H2A.X 完全取代了典型的 H2A，可能会改善 DDR 并影响依赖于 DDR 的减数分裂等过程。在果蝇中，H2A.X 与 H2A.Z 融合产生独特的 H2Av 变体。这种融合丰富了异染色质处的 DDR，这可能限制 DDR- 基于基因贫乏区域的转座事件。识别这些进化的功能后果创新，申请人将重新设计酵母和果蝇中的祖先真核 H2A 库。具体而言，在酿酒酵母中，申请人将设计一个核心 H2A 和两个变体 H2A.X 和 H2A.Z，阻止 H2A.X 成为核心组蛋白（目标 1）。在黑腹果蝇中，融合组蛋白 H2Av 将是分为 H2A.X 和 H2A.Z，解偶联 DDR 和基因调控功能（目标 2）。更改为有机体染色质包装以及相关的生物学功能，包括 DNA 修复、减数分裂、生育力和换位将受到询问。在目标 3 中，申请人将应用在目标 1 和 2 中学到的工具来学习真核核心H2A的分歧。组蛋白具有大量翻译后的尾部序列修饰并在高级染色质包装和蛋白质相互作用中发挥关键作用。高真核组蛋白尾部的序列差异表明尾部可以促进独特的谱系特异性功能。通过在酵母和果蝇中设计不同的尾部序列，Aim 3 将揭示染色质的变化包装，以及酵母交配和静止等过程的变化，以及生育和发育在苍蝇中。为了开展这项工作，申请人需要接受遗传学、基因组学和表型分析方面的培训两种模式生物：酵母和果蝇。通过利用她在进化分析方面的专业知识和力量同时在酵母和果蝇中建立完善的工具，未来申请人将研究其生物学基础以及组蛋白创新的后果，包括她自己之前的发现和共同进化机制。