GENETIC ANALYSIS OF HUMAN BRAIN DEVELOPMENT

人脑发育的遗传分析

• 批准号: 2025413
• 负责人: Maximilian Muenke
• 金额: $ 23.13万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2025413
• 关键词: artificial chromosomes; brain; cell line; chromosome deletion; chromosome translocation; chromosome walking; congenital brain disorder; cytogenetics; developmental genetics; developmental neurobiology; early embryonic stage; gene expression; genetic mapping; genetic markers; human genetic material tag; human subject; hybrid cells; in situ hybridization; molecular cloning; neurogenesis; neurogenetics; northern blottings; protein structure function; pulsed field gel electrophoresis; southern blotting

Development of the human brain during early embryogenesis has been studied mostly on a descriptive level. Analysis of genes and gene produets necessary for the morphogenesis of the central nervous system will contribute to our understanding not only of normal brain development, but also of the etiology of abnormal formation as seen in congenital brain anomalies. Isolation of genes involved in early embryonic brain formation can be accomplished through molecular studies of cells from individuals with abnormal brain development. The holoprosencephaly (HPE) sequence is such a structural anomaly characterized by abnormal midline development of the brain and face. The clinical spectrum is well described, varying from severe forms with a single brain ventricle and cyclopia, which are incompatible with postnatal life, to milder forms in patients with mental retardation and other developmental disabilities. The genetic basis of holoprosencephaly is heterogeneous with both familial occurrence and sporadic cases due to specific chromosome anomalies. A set of related hypotheses are proposed: First, genes for normal brain development are located in chromosomal regions preferentially associated with holoprosencephaly. Second, gene arrangements, e.g. translocations or deletions, alter gene expression, leading to the clinical features of the holoprosencephaly sequence. Third, expression of these genes is assumed to occur as early as during the gastrulation and neurulation stages in the third week of embryogenesis. To address these hypotheses the proposed research will concentrate on one form of holoprosencephaly associated with a newly identified chromosomal t(7;9) translocation breakpoint in 7q36 and a number of deletions encompassing this breakpoint. 1. DNA markers from the 7q36 region will be localized to generate a detailed physical map around the HPE breakpoint. 2. Probes in and around this breakpoint will be used to identify large fragments of human DNA cloned into yeast artificial chromosomes (YACs). 3. Available cDNA libraries from early mouse embryos and human fetal brain-specific cDNA libraries will be screened with YACs from the HPE breakpoint region. 4. cDNA clones from these libraries that map to the HPE breakpoint in 7q36 are candidates for a gene necessary for normal brain development. Analysis of expression and function of this gene will result in a better understanding of normal brain formation in humans and, ultimately, elucidate the basic DNA defect which programs its abnormal development as seen in holoprosencephaly.

早期胚胎发生过程中人脑的发育已被研究 主要是在描述性的层面上。基因和基因产物分析 中枢神经系统形态发生所必需的 不仅有助于我们理解正常的大脑发育，而且 也是先天性大脑异常形成的病因学 异常。分离参与早期胚胎大脑形成的基因 可以通过对个体细胞的分子研究来完成 大脑发育异常。 前脑无裂畸形 (HPE) 序列就是这样一种结构异常 其特征是大脑和面部中线发育异常。这 临床谱已得到很好的描述，从严重的形式到具有 单脑室和独眼，与产后不相容 精神发育迟滞和其他疾病患者的轻度形式 发育障碍。前脑无裂畸形的遗传基础是 具有家族性和散发性的异质性 特定的染色体异常。 提出了一组相关假设：第一，正常大脑的基因 发育位于优先相关的染色体区域 伴有前脑无裂畸形。第二，基因排列，例如易位或 缺失，改变基因表达，导致临床特征 前脑无裂序列。第三，假设这些基因的表达 早在原肠胚形成和神经形成阶段就发生 胚胎发生第三周。 为了解决这些假设，拟议的研究将集中于一个 与新发现的染色体相关的前脑无裂畸形 7q36 中的 t(7;9) 易位断点和大量缺失 包围这个断点。 1. 7q36 区域的 DNA 标记将被 本地化以生成 HPE 断点周围的详细物理图。 2. 该断点及其周围的探针将用于识别大的 克隆到酵母人工染色体（YAC）中的人类 DNA 片段。 3. 早期小鼠胚胎和人类胎儿的可用 cDNA 文库 将使用 HPE 的 YAC 筛选大脑特异性 cDNA 文库 断点区域。 4. 来自这些文库的 cDNA 克隆映射到 HPE 7q36 中的断点是正常大脑必需基因的候选点 发展。 对该基因的表达和功能的分析将产生 更好地了解人类正常的大脑形成， 最终，阐明导致其异常的基本DNA缺陷 前脑无裂畸形中所见的发育。