Molecular Basis of Isl-1 Induced Birth Defects

描述(申请人提供)：这项研究的目的是利用Islet-1(ISL-1)转基因小鼠模型，研究由母体糖尿病引起的出生缺陷的分子基础，糖尿病胚胎病变的特征。转录因子LSL-L的表达是胰腺正常发育所必需的。我们发现，ISL-1基因的异常可导致类似于人类糖尿病胚胎病变的骶尾部发育不全。这些结果表明，在糖尿病妊娠中，胚胎LSL-1的表达可能是失调的。因此，ISL-1转基因小鼠模型为研究遗传反应提供了一个合适的模型，并将被用来阐明IS！-！下游的分子途径和可能的生物/转录靶点。使用二进制转基因小鼠模型产生ISI-I转基因基因。我们可以控制基因剂量的增量差异，这取决于胚胎的反式激活或反式反应基因是半合子还是纯合子。这使我们能够通过关注两个参数来识别ISL-1的转录靶点，即基因剂量和发育调整点(E8.5-E12.5)。将追求三个具体目标：i)使用定量RT-PCR和原位杂交来评估候选LSL-1靶标。2)通过基因表达谱鉴定新的ISL-1靶点。将使用15K小鼠发育基因cDNA收集和专门为该项目设计的解释框架。尤其是。高基因剂量转基因基因的微阵列分析。导致更严重的表型，将有助于确定强制性靶基因的缺陷。3)候选和新的ISL-L靶点的基因表达研究将用于比较LSL-1转基因和化学(四氧嘧啶)诱导的糖尿病胚胎病的发育缺陷。遗传模式和药理模式的比较！将确定糖尿病胚胎病和我们的ISL-1转基因模型中的发育缺陷是否通过共同的分子扰动而产生。这项研究将阐明导致骶尾发育不全的分子途径。这些信息可进一步用于为妊娠期糖尿病母亲制定治疗策略，以抵消导致糖尿病胎膜病变的分子变化，并减少因发育缺陷而导致的新生儿发病率。

DESCRIPTION (provided by applicant): The purpose of this research is to investigate the molecular basis of birth defects, characteristic of diabetic embryopathy, resulting from maternal diabetes using an Islet-1 (Isl-1) transgenic mouse model. Expression of the transcription factor lsl-l is necessary for normal pancreatic development. We found that dysreguIation of Isl-1 causes sacral/caudal agenesis similar to human dIabetic embryopathy. These results suggest that embryonic lsl-1 expression may be dysregulated in diabetic pregnancies. The Isl-1 transgenic mouse model, therefore provides a suitable model for studying the genetic response and will be utilized to elucidate the molecular pathways and possible biological/transcriptional targets downstream of Is!-!. Using a binary transgenic mouse model to generate IsI- I transgenics. we have control over incremental differences in gene dosage, dependent on whether the embryo is hemizygous or homozygous for the transactivator or transresponder gene. This allows us to identify transcriptional targets of Isl-1 by focusing on two parameters, gene dosage and developmental tune point (E8.5-E 12.5). Three specific aims will be pursued: I) Evaluation of candidate lsl-1 targets using quantitative RT-PCR and in situ hybridizations. 2) Identification of new Isl-1 targets by gene expression profiling. The 15K mouse developmental gene cDNA collection and an interpretation framework specifically designed for this project will be used. in particular. microarray analysis of transgenics with high gene dosage. resulting in a more severe phenotype, will help identify compulsory target genes to the defect. 3) Gene expression studies on candidate and new Isl-l targets will be used to compare the developmental defects in lsl-1 transgenics to chemically (Alloxan) induced diabetic embrvopathies. Comparison of the genetic and the pharmacological mode! will determine whether developmental defects in diabetic embryopathv and in our Isl-1 transgenic model arise through common molecular perturbations. This study will elucidate the molecular pathways leading to sacral/caudal agenesis. The information may be further used to devise treatment strategies for diabetic mothers during pregnancy to offset the molecular changes that Lead to diabetic embrvopathies and to reduce newborn morbidity due to the developmental defect.