USING MICROSATELLITES TO ANALYZE CYTOMEGALOVIRUS STRAINS

描述(改编自申请人的摘要)辨别能力 形态上相同的病原体菌株对于适当的 巨细胞病毒等机会性感染的诊断和治疗 在艾滋病患者身上。研究人员提议使用微卫星来 调查有关传播、毒力和毒品的重要问题 对疱疹病毒、巨细胞病毒产生抗药性。 而基因和毒力之间的关系已经被检测到 遗传标记、微卫星可能提供大量新的标记 以帮助了解CMV的毒力。微卫星序列有 由于以下原因而累积长度突变的直接重复序列的短阵列 频繁出现复制滑移错误。调查人员发现， 即使在较小的基因组中(8000个碱基到50个碱基)，这些基因座的出现频率也足够高 使它们成为一个非常有用的，但基本上未被开发的遗传标记来源 在微生物中。对这类基因座进行DNA测序通常会检测到 具有相同的长度但不同的序列，使它们能够区分 在各种菌株中具有很高的确定性。在初步调查中，有四个 这种重复序列存在于巨细胞病毒基因组中， 研究人员还确定了适合研究的基因座。 微小隐孢子虫、肺孢子虫、隐球菌和分枝杆菌。这个 这类生物的微卫星标记的开发代表了一种新的 机会性感染的特征的方法，并可能允许 他们将跟踪疫情的重大细节。申请者打算 使用这种方法来检查基因、毒力和 巨细胞病毒的耐药性。这些信息可能有助于治疗和 预防。来自白色念珠菌的研究人员的数据表明了这一可行性 用于菌株鉴别和研究的微卫星分型 沙门氏菌分离株对抗真菌药物的耐药性演变 HIV阳性的个人。将采用类似的方法来研究 对宿主有广泛影响的巨细胞病毒株 这些细胞很容易产生对抗病毒药物有抵抗力的突变体。

DESCRIPTION (adapted from applicant's abstract) The ability to distinguish morphologically identical strains of pathogens is critical to proper diagnosis and treatment of opportunistic infections such as cytomegalovirus in AIDS patients. The investigators propose to use microsatellites to investigate important questions of transmission, virulence and drug resistance in the herpes-like virus, cytomegalovirus. While relations between genotype and virulence have been detected for other genetic markers, microsatellites may provide a large number of new markers to aid in the understanding of CMV virulence. Microsatellite sequences are short arrays of direct repeats which accumulate length mutations due to frequent replication slippage errors. The investigators have found that these loci occur frequently enough even in small genomes (8000 bp to 50 Mbp) to make them a very useful, and largely untapped, source of genetic markers in microorganisms. DNA sequencing of such loci often detects alleles that have the same length but a different sequence, allowing them to distinguish among various strains with high certainty. In a preliminary survey, four such repeats have been located in the cytomegalovirus genome, and the investigators have also identified suitable loci for study in Cryptosporidium parvum, Pneumocystis, Cryptococcus, and Mycobacterium. The development of microsatellite markers for such organisms represents a novel approach to the characterization of opportunistic infections, and may allow them to follow outbreaks in significant detail. The applicants intend to use this approach to examine relationships among genotype, virulence and drug resistance in cytomegalovirus. This information may aid in therapy and prevention. The investigators' data from C. albicans show the feasibility of microsatellite typing for distinguishing among strains and for studying the evolution of resistance to fungistatic agents in strains isolated from HIV-positive individuals. Similar approaches will be taken to the study of strains of cytomegalovirus, which have a great range of effects on host cells and which readily give rise to mutants resistant to antiviral agents.