REGULATION OF GENE EXPRESSION IN THE DEVELOPING RETINA

这项建议的重点是在基因调控机制， 发展中的鸟类视网膜，重点是基因表达， 米勒神经胶质细胞。 审查中的监管制度 包括神经胶质细丝蛋白和糖皮质激素诱导， 谷氨酰胺合成酶。细丝蛋白是肌动蛋白交联的 被认为在调节细胞形状中起重要作用的药物 和运动性。 我们建议对细丝蛋白基因结构进行表征， 通过基因组和cDNA克隆， 细丝蛋白的结构，通过DNA测序， cDNA克隆。 随后的工作将集中在作用 染色质结构的改变在限制神经胶质细丝中起作用， 在终末分化过程中向Muller细胞表达， 用克隆的杂交探针进行核酸酶敏感性测定。 我们 长期目标包括检查调控DNA 细丝蛋白基因上的序列被认为是穆勒所需的 细胞特异性基因表达，通过DNA介导的转染 穆勒细胞衍生的培养“扁平细胞”。 使用克隆 杂交探针，我们将研究分子机制（S） 导致谷氨酰胺含量增加数百倍 合成酶蛋白在终末分化过程中的作用 视网膜，仅在穆勒神经胶质细胞。 重点将 放置在糖皮质激素诱导剂的作用和 视网膜细胞间接触的破坏机制 器官培养物抑制谷氨酰胺合成酶诱导。 通过 这些基因调控研究，我们希望能提高我们的 了解调节Muller细胞的机制 在视网膜的终末分化期间的表型。

This proposal focuses on mechanisms of gene regulation in the developing avian retina, with emphasis on genes expressed in the Muller glial cells. The regulatory systems under examination include glial filamin and the glucocorticoid hormone induction of glutamine synthetase. Filamin proteins are actin cross linking agents thought to play an important role in regulating cell shape and motility. We propose to characterize filamin gene structure, through genomic and cDNA cloning, and determine the primary structure of the filamin protein, through DNA sequencing of cDNA clones. Subsequent efforts will focus on the role alterations in chromatin structure play in restricting glial filamin expression to Muller cells during terminal differentiation using nuclease sensitivity assays with cloned hybridization probes. Our long term objectives include examination of regulatory DNA sequences on the filamin gene postulated to be required for Muller cell specific gene expression, by DNA-mediated transfection of Muller cell derived cultured "flat cells". Using cloned hybridization probes, we will examine the molecular mechanism(s) responsible for eliciting the several hundred fold rise in glutamine synthetase enzyme protein during terminal differentiation of the retina, exclusively in the Muller glial cells. Emphasis will be placed on the role of the glucocorticoid hormone inducer and the mechanism by which disruption of cell-cell contacts in retina organ cultures inhibits glutamine synthetase induction. Through these gene regulatory studies, we hope to enhance our understanding of the mechanisms mediating the Muller cell phenotype during terminal differentiation of the retina.