Molecular Basis of Isl-1 Induced Birth Defects

描述（由申请人提供）：本研究的目的是利用胰岛-1 （isl1）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，即糖尿病胚胎病的特征。转录因子lsl- 1的表达是正常胰腺发育所必需的。我们发现is -1的失调导致了类似于人类糖尿病胚胎病的骶/尾发育不全。这些结果表明，胚胎lsl-1表达可能在糖尿病妊娠中失调。因此，Is -1转基因小鼠模型为研究遗传应答提供了一个合适的模型，并将用于阐明Is -1下游的分子途径和可能的生物学/转录靶点。利用二元转基因小鼠模型生成IsI- I转基因。我们可以控制基因剂量的增量差异，这取决于胚胎是半合子还是纯合子的反激活基因或应答基因。这使我们能够通过关注两个参数，基因剂量和发育调点（e8.5 - e12.5）来确定il -1的转录靶点。将追求三个具体目标：1)使用定量RT-PCR和原位杂交评估候选lsl-1靶点。2)通过基因表达谱鉴定新的is -1靶点。将使用15K小鼠发育基因cDNA收集和专门为本项目设计的解释框架。在特定的。高剂量转基因基因的微阵列分析。导致更严重的表型，将有助于确定强制靶基因的缺陷。3)候选靶点和新靶点的基因表达研究将用于比较lsl-1转基因与化学（四氧嘧啶）诱导的糖尿病胚胎病变的发育缺陷。遗传模式与药理学模式的比较！将确定糖尿病胚胎病和我们的il -1转基因模型中的发育缺陷是否由常见的分子扰动引起。这项研究将阐明导致骶/尾发育的分子途径。这些信息可以进一步用于为怀孕期间的糖尿病母亲设计治疗策略，以抵消导致糖尿病胚胎病变的分子变化，并减少由于发育缺陷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.