Genetic Dissection of Lipopolysaccharide Response

描述（由申请人提供）：使用生物化学和遗传学方法的组合分析了脂多糖（LPS）信号传导途径。然而，并不是所有参与LPS识别的蛋白质都已被鉴定。为了找到更多的人，几个近交系的小鼠进行了评估，对他们的LPS反应和遗传基础的差异，在这种反应进行了检查。其中，BALB/C和C3 H/HeN对LPS的反应存在显著差异。为了进一步确定TLR 4 LPS应答之间的关系，分析（BALB/C x C3 H/HeN）F2杂交小鼠的LPS应答并对TLR 4基因座进行基因分型。这些数据表明，虽然在BALB/C和C3 H/HeN小鼠之间观察到TLR 4存在功能多态性，但其他基因明显参与LPS应答。为了对这些基因作图，扩大F2小鼠组并进行全基因组筛选，其中所有子代都对TLR 4基因座进行基因分型。对80个减数分裂的遗传分析表明，BALB/C小鼠对LPS的低反应与染色体6和17上的位点有关。为了进一步表征候选物并提高遗传作图的分辨率，构建了两个同源菌株：一个在C3 H/HeN背景上具有TLR 4的BALB/C等位基因，另一个在BALB/C背景上具有TLR 4的HeN等位基因。进一步分析这些菌株以确定它们对LPS的应答水平。两个新的基因座，称为Lpm 1和Lpm 2，可以假定有助于LPS反应。Lpm 1和Lpm 2的阐明将代表一个重要的进展，因为许多已知有助于复杂性状的基因可以通过这种方法鉴定。采用类似的策略分析F2杂交动物中对肽聚糖的杂交反应。在小鼠模型中阐明抗细菌反应的精确机制无疑将有助于研究宿主对人类感染性疾病的抗性。

DESCRIPTION (provided by applicant): The lipopolysaccharide (LPS) signaling pathway has been analyzed using combination of biochemical and genetic methods. However, not all of the proteins that participate in LPS recognition have been identified. In order to find more of them, several inbred strains of mice were evaluated on their LPS response and genetic basis of the differences in this response was examined. Among them, BALB/C and C3H/HeN strains differ significantly in their response to LPS. To further determine the relationship between TLR4 LPS response, (BALB/C x C3H/HeN) F2 intercross mice were analyzed on their LPS response and genotyped for TLR4 locus. These data show that although there is functional polymorphism in TLR4 observed between BALB/C and C3H/HeN mice, additional genes are clearly involved in LPS response. In order to map these genes, the panel of F2 mice was expanded and subjected to genome wide screening with all progeny genotyped for TLR4 locus. Genetic analysis of 80 meioses revealed that hyporesponse of BALB/C mice to LPS is linked to loci on chromosomes 6 and 17. To further characterize candidates and to improve resolution of genetic mapping, two congenic strains were constructed: one with BALB/C allele of TLR4 on C3H/HeN background and another - with HeN allele of TLR4 on BALB/C background. These strains were further analyzed to determine the level of their response to LPS. Two new loci, termed Lpml and Lpm2, may be assumed to contribute to the LPS response. The elucidation of Lpml and Lpm2 will represent an important advance, in that many genes that are known to contribute to complex traits can be identified by such approach. Similar strategy was employed for analysis of intercross response to peptidoglycan in F2 intercross animals. Elucidation of a precise mechanism of anti-bacterial response in a mouse model will undoubtedly contribute to the studies of host resistance to infectious diseases in humans.