Dosage-dependent regulation in hybridization

杂交中的剂量依赖性调节

基本信息

批准号：
7669160
负责人：
LUCA COMAI
金额：
$ 25.57万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-09-25 至 2012-08-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The difficulty of forming interploidy or interspecies hybrids of plants demonstrates the importance of matched parents in reproduction. "Unbalanced" parental contributions cause seed failure. Interestingly, balance is a genetic trait and not only a consequence of genome dosage, as certain diploids can be better matched with tetraploid species than with other diploid species. We hypothesize that regulation of chromatin and growth are dosage-sensitive processes that affect the success of plant hybridization. This hypothesis is supported by the following preliminary observations: Arabidopsis parents with identical genotypes produce dead or viable hybrid seeds depending on the parental genomic ratio. Seeds from interspecific crosses display dosage-dependent derepression of the heterochromatic repeat ATHILA, and of the imprinted, paternally- expressed, transcription factor PHE1. Decreased activity of PHE1 suppresses death in interspecific crosses. Using genetic variation in parental dosage potential, we have characterized the genetics of interploidy and interspecies hybridization finding that both are controlled by few QTL. Maternal sensitivity to interploidy crosses responds to the transcription regulator TTG2, which acts in maternal tissue to modulate endosperm growth. Decreased activity of TTG2 results in seed survival and is likely to explain an observed major effect QTL. Based on these results, we propose to: 1. Determine the molecular basis of QTL affecting interspecific and interploidy postzygotic incompatibility. 2. Investigate the transcriptional consequences of the fusion of mismatched gametes in both interspecific and interploidy matings. 3. Investigate the causes and consequences of ATHILA and PHERES1 misexpression and the developmental consequences of incompatibility. The proposed research will fill a lacuna in our understanding of factors governing postzygotic compatibility in plants and help address the function of chromatin and growth regulators as dosage sensitive components. Although aneuploidy, the unbalanced dosage of genomic elements, is associated with cancer and causes several genetic diseases such as Down Syndrome, it is difficult to study its molecular basis in humans. The plant Arabidopsis provides the opportunity to dissect dosage determinants in a model eukaryote. The knowledge gained in this study may help understand dosage-related diseases and possibly help in their prevention and treatment.

描述（由申请人提供）：形成植物的相互作用或种间杂种的困难表明了匹配父母在生殖中的重要性。 “不平衡”父母的贡献会导致种子衰竭。有趣的是，平衡是一种遗传特征，不仅是基因组剂量的结果，因为某些二倍体可以与四倍体物种更好地匹配，而不是其他二倍体物种。我们假设调节染色质和生长是影响植物杂交成功的剂量敏感过程。该假设得到以下初步观察的支持：具有相同基因型的拟南芥父母会根据父母的基因组比率产生死亡或可行的杂种种子。来自种间杂交的种子显示出异质性重复athila的剂量依赖性压缩，以及印迹，含水量表的转录因子PHE1的剂量依赖性折叠。 PHE1活性降低会抑制种间杂交中的死亡。使用亲本剂量潜力的遗传变异，我们表征了相互作用和种间杂交发现的遗传学，这些发现两者都受到很少的QTL控制。孕产妇对互相交叉的敏感性对转录调节剂TTG2做出反应，该转录调节剂TTG2在母体组织中起作用以调节胚乳的生长。 TTG2的活性降低会导致种子存活，并且可能解释了观察到的主要效应QTL。基于这些结果，我们提出：1。确定QTL的分子基础，影响种间和互相互相的不相容性。 2。研究不匹配的配子融合在种间和相互作用的融合中的转录后果。 3。研究Athila和pheres1 misexpress的原因和后果以及不兼容的发展后果。拟议的研究将填补我们对植物中同变性兼容性的因素的理解，并有助于解决染色质和生长调节剂作为剂量敏感成分的功能。尽管基因组元素的不平衡剂量的非整倍性与癌症有关，并引起多种遗传疾病，例如唐氏综合症，但很难研究其在人类中的分子基础。植物拟南芥提供了剖析真核生物中剂量决定因素的机会。这项研究中获得的知识可能有助于了解与剂量有关的疾病，并可能有助于预防和治疗。