A narrow quantitative trait locus in C. elegans coordinately affects longevity, thermotolerance, and resistance to paraquat.
A narrow quantitative trait locus in C. elegans coordinately affects longevity, thermotolerance, and resistance to paraquat.
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DOI：
10.3389/fgene.2011.00063
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发表时间：
2011
影响因子：
3.7
通讯作者：
Shmookler Reis RJ
中科院分区：
文献类型：
--
作者：
Vertino A;Ayyadevara S;Thaden JJ;Shmookler Reis RJ
通过数量性状位点的连锁定位，我们先前确定了至少11种显著调节秀丽隐杆线虫寿命（LS）的天然遗传变异，其中许多可能无法通过敲除或突变筛选发现。染色体IV上标记stP13和stP35之间的一个区域对三个株系间杂交的寿命有显著影响（P < 10−9）。为了确定该区间的极限，我们现在通过基于标记的选择在20个回交代中构建了两个独立的系，在CL2a背景下从菌株Bergerac-BO中分离出stP13-stP35区间。在两种环境下，这些基因系与LS中的CL2a有显著差异（均P < 0.001）。然后，我们筛选了两侧标记的交换，以分离划分该区域的重组，因为精细绘制重叠异等位基因跨度的边界可以大大缩小所涉及的间隔。与保留Bergerac-BO等位基因的重组体相比，携带stP35上CL2a等位基因的重组体始终寿命更长（P < 0.001），并且对温度升高和百草枯的抗性更强（各为1.7倍，P < 0.0001），但对紫外线或过氧化胁迫的保护很少。两轮重组筛选，随后是断点的精细定位和生存测试，将间隔缩小到0.18 Mb (13.35-13.53 Mb)，其中包含26个假定基因和6个小核rna——功能评估的目标数量可控。
By linkage mapping of quantitative trait loci, we previously identified at least 11 natural genetic variants that significantly modulate Caenorhabditis elegans life-span (LS), many of which would have eluded discovery by knock-down or mutation screens. A region on chromosome IV between markers stP13 and stP35 had striking effects on longevity in three inter-strain crosses (each P < 10−9). In order to define the limits of that interval, we have now constructed two independent lines by marker-based selection during 20 backcross generations, isolating the stP13–stP35 interval from strain Bergerac-BO in a CL2a background. These congenic lines differed significantly from CL2a in LS, assayed in two environments (each P < 0.001). We then screened for exchange of flanking markers to isolate recombinants that partition this region, because fine-mapping the boundaries for overlapping heteroallelic spans can greatly narrow the implicated interval. Recombinants carrying the CL2a allele at stP35 were consistently long-lived compared to those retaining the Bergerac-BO allele (P < 0.001), and more resistant to temperature elevation and paraquat (each ∼1.7-fold, P < 0.0001), but gained little protection from ultraviolet or peroxide stresses. Two rounds of recombinant screening, followed by fine-mapping of break-points and survival testing, narrowed the interval to 0.18 Mb (13.35–13.53 Mb) containing 26 putative genes and six small-nuclear RNAs – a manageable number of targets for functional assessment.