Faculty of Health Sciences, Ben-Gurion University, Barzilai Medical Center Campus, Ashkelon, Israel.
Physiol Genomics. 2010 Aug;42(3):445-55. doi: 10.1152/physiolgenomics.00042.2010. Epub 2010 Jun 8.
The aim of the study was to initiate a sex-specific investigation of the molecular basis of diabetes, using a genomic approach in the Cohen Diabetic rat model of diet-induced Type 2 diabetes. We used an F2 population resulting from a cross between Cohen Diabetic susceptible (CDs) and resistant (CDr) and consisting of 132 males and 159 females to detect relevant QTLs by linkage and cosegregation analyses. To confirm the functional relevance of the QTL, we applied the "chromosome substitution" strategy. We identified candidate genes within the quantitative trait locus (QTL) and studied their differential expression. We sequenced the differentially expressed candidate genes to account for differences in their expression. We confirmed in this new cross in males a previously detected major QTL on rat chromosome 4 (RNO4); we identified in females this major QTL as well. We found three additional diabetes-related QTLs on RNO11, 13, and 20 in females only. We pursued the investigation of the QTL on RNO4 and generated a CDs.4(CDr) consomic strain, which provided us with functional confirmation for the contribution of the QTL to the diabetic phenotype in both sexes. We successfully narrowed the QTL span to 2.6 cM and identified within it six candidate genes, but only two of which, Ica1 (islet cell autoantigen 1) and Ndufa4 (NADH dehydrogenase ubiquinone) were differentially expressed between CDs and CDr. We sequenced the exons and promoter regions of Ica1 and Ndufa4 but did not identify sequence variations between the strains. The detection of the QTL on RNO4 in both sexes suggests involvement of Ica1, Ndufa4, the Golgi apparatus, the mitochondria and genetic susceptibility to dietary-environmental factors in the pathophysiology of diabetes in our model. The additional sex-specific QTLs are likely to account for differences in the diabetic phenotype between the sexes.
本研究旨在利用基因组学方法，以 Cohen 糖尿病大鼠（一种饮食诱导的 2 型糖尿病模型）为研究对象，开展糖尿病分子基础的性别特异性研究。我们使用了 Cohen 糖尿病易感（CDs）和抗性（CDr）大鼠杂交产生的 F2 群体，该群体由 132 只雄性和 159 只雌性组成，通过连锁和共分离分析来检测相关的 QTL。为了确认 QTL 的功能相关性，我们应用了“染色体替换”策略。我们确定了数量性状基因座（QTL）内的候选基因，并研究了它们的差异表达。我们对差异表达的候选基因进行测序，以解释它们表达水平的差异。我们在这个新的雄性交叉中证实了先前在大鼠第 4 号染色体（RNO4）上检测到的一个主要 QTL；我们还在雌性中发现了这个主要 QTL。我们仅在雌性中发现了另外三个与糖尿病相关的 QTL，位于 RNO11、13 和 20 号染色体上。我们对 RNO4 上的 QTL 进行了进一步研究，并生成了 Cohen 糖尿病易感（CDs）.4（CDr）同源染色体品系，这为 QTL 对两性糖尿病表型的贡献提供了功能确认。我们成功地将 QTL 范围缩小到 2.6 cM，并在其中鉴定了 6 个候选基因，但只有其中的 Ica1（胰岛细胞自身抗原 1）和 Ndufa4（NADH 脱氢酶泛醌）在 CDs 和 CDr 之间存在差异表达。我们对 Ica1 和 Ndufa4 的外显子和启动子区域进行了测序，但在两个品系之间没有发现序列变异。在两性中都检测到 RNO4 上的 QTL 提示 Ica1、Ndufa4、高尔基体、线粒体和遗传易感性在我们的模型中参与了糖尿病的病理生理学，这些因素易受饮食环境因素的影响。额外的性别特异性 QTL 可能是导致两性之间糖尿病表型差异的原因。
