The Significance of Polymorphic Endogenous Retroviruses to Human Mental Health

描述(由申请人提供)： 人类内源性逆转录病毒(HERV)是逆转录病毒DNA整合到生殖细胞中的产物。HERV-K(HML-2)前病毒代表最近整合的HERV组。尽管大多数是有缺陷的，但HML-2在部分或全部基因中存在完整的开放阅读框架。HML-2一直处于纯化选择下，暗示着再感染，它们的插入率在原始人进化过程中保持不变。通过病毒颗粒、基因组RNA或转录本的存在，HML-2的表达与大脑疾病，特别是精神分裂症有关。HERV在人脑组织中表达的后果目前还知之甚少。我们假设存在一个具有复制能力的HML-2前病毒，它的表达对附近的细胞有负面的遗传影响。虽然感染性病毒可能来自反式病毒的多个位点，但一个完整的前病毒可以单独产生感染性病毒，最有可能的候选者是最近的插入。我们建议使用杂交、聚合酶链式反应、克隆和测序相结合的方法在人类中鉴定新的HML-2多态插入。每个新发现的HML-2前病毒和疾病的发病率将在人类DNA样本的高通量PCR筛查中进行分析。最后，我们将使用印迹和聚合酶链式反应技术，对照年龄匹配的对照组，寻找从精神分裂症相关脑组织提取的DNA中HML-2的插入。在这种分析中检测到的新的克隆性HML-2插入将为表达的、具有复制能力的HML-2前病毒提供强有力的证据。新的整合与宿主编码区的紧密结合将被认为是转录改变模式的初步证据，并将为进一步研究提供基础。在精神分裂症患者中有显著发生率的遗传性HML-2前病毒将是一个重要的发现。这一知识不仅会影响疾病的诊断，而且可以适当调整预防和治疗战略，以替代目前的方法。精神分裂症目前影响着大约1%的美国人口，每年给公众造成近1000亿美元的损失(国家心理健康研究所)。最近整合的前病毒可能通过遗传内源性基因的表达与这种精神障碍有关，其中最有可能属于HERV-K(HML-2)逆转录病毒组。这项建议的目的是通过建立遗传性前病毒与精神分裂症的遗传联系，或者证明精神分裂症患者和年龄匹配的对照组的脑组织中存在新的前病毒，来阐明HML-2表达和精神分裂症之间的关系。

DESCRIPTION (provided by applicant): Human endogenous retroviruses (HERVs) result from the integration of retroviral DMA into germ cells. The HERV-K(HML-2) proviruses represent the most recently integrated HERV group. Although most are defective, HML-2 proviruses with intact open reading frames in some or all genes exist. HML-2 have been under purifying selection, suggesting reinfection, and their insertion rate appears constant during hominid evolution. HML-2 expression has been associated with brain disorders, particularly schizophrenia, by the presence of viral particles, genomic RNA, or transcripts. The consequences of HERV expression in human brain tissue are poorly understood. We hypothesize the existence of an replication competent HML-2 provirus whose expression has negative genetic effects on nearby cells. Although infectious viruses could potentially be generated from multiple loci in trans, an intact provirus could alone produce infectious virus, the most likely candidates for which are very recent insertions. We propose to identify novel HML-2 polymorphic insertions in humans using a combination of blotting, PCR, cloning, and sequencing. The incidence of each newly identified HML-2 provirus and disease will be analyzed in a high-throughput PCR screening of human DNA samples. Finally, we will look for HML-2 insertions in DNA extracted from schizophrenia-associated brain tissue against age-matched controls using blotting and PCR techniques. New, clonal HML-2 insertions detected in such an analysis would provide strong evidence of an expressed, replication competent HML-2 provirus. Close proximity of a new integration to a host coding region will be considered as preliminary evidence for a model of transcriptional alteration, and would provide the basis for further studies. An inherited HML-2 provirus with a significant incidence in patients with schizophrenia would be an important discovery. This knowledge would affect not only the diagnosis of the disease, but strategies for prevention and treatment could be adjusted appropriately as an alternative to current methods. Schizophrenia currently affects about one percent of the United States population and costs the public nearly $100 billion each year (National Institutes of Mental Health). Recently integrated proviruses may be genetically linked to this mental disorder through the expression of inherited endogenous loci, the most likely of which belong to the HERV-K(HML-2) group of retroviruses. The goal of this proposal is to clarify the relationship between HML-2 expression and schizophrenia by either establishing a genetic linkage of an inherited provirus with the disorder, or demonstrating the presence of novel proviruses in brain tissue from the patients diagnosed with schizophrenia versus age-matched controls.