The Significance of Polymorphic Endogenous Retroviruses to Human Mental Health

描述（由申请人提供）： 人内源性逆转录病毒（HERV）由逆转录病毒DNA整合到生殖细胞中产生。HERV-K（HML-2）前病毒代表最近整合的HERV组。虽然大多数是有缺陷的，但在某些或所有基因中具有完整开放阅读框架的HML-2前病毒存在。HML-2一直处于纯化选择中，表明再次感染，它们的插入率在人科进化过程中似乎是恒定的。HML-2表达与脑部疾病，特别是精神分裂症有关，因为存在病毒颗粒、基因组RNA或转录物。人类脑组织中HERV表达的后果知之甚少。我们假设存在一个可复制的HML-2前病毒，其表达对附近的细胞有负面的遗传效应。虽然感染性病毒可能从多个反式基因座产生，但完整的前病毒可以单独产生感染性病毒，最可能的候选者是最近的插入。我们建议确定新的HML-2多态性插入在人类使用的组合印迹，PCR，克隆和测序。将在人DNA样本的高通量PCR筛选中分析每种新鉴定的HML-2前病毒和疾病的发生率。最后，我们将寻找HML-2插入DNA提取精神分裂症相关的脑组织对年龄匹配的控制使用印迹和PCR技术。在这样的分析中检测到的新的克隆HML-2插入将提供表达的具有复制能力的HML-2前病毒的强有力证据。一个新的整合到宿主编码区的紧密接近将被认为是转录改变模型的初步证据，并将为进一步的研究提供基础。精神分裂症患者中具有显著发病率的遗传性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，作为目前方法的替代。精神分裂症目前影响着大约百分之一的美国人口，每年花费公众近1000亿美元（美国国立精神卫生研究院）。最近整合的前病毒可能通过遗传内源性基因座的表达与这种精神障碍有遗传联系，其中最有可能属于HERV-K（HML-2）组逆转录病毒。本提案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，或证明诊断为精神分裂症的患者与年龄匹配的对照组的脑组织中存在新型前病毒，来阐明HML-2表达与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.