Regulation and Function of the Erythroid Transcription Factor NF-E2

转录因子NF-E2（一种由两种蛋白p45和p18组成的复合物）结合到红系基因调控区域的特定DNA序列上，似乎是红细胞成熟过程中这些基因转录激活所必需的。PI最近发现，小鼠红细胞白血病细胞（MEL），一种红细胞模型系统，缺乏cAMP依赖性蛋白激酶（a激酶），一种参与信号转导的酶，其成熟和激活红细胞基因的能力严重受损。同时也有NF-E2的异常结合。初步实验表明，a激酶通过磷酸化p45和调节p45和p18复合物的形成来调节NF-E2。本基金的实验将进一步检验这一点。A激酶对p45的磷酸化将通过确定哪些氨基酸被磷酸化来研究，看看这种磷酸化是否发生在红细胞成熟过程中，并确定p45的磷酸化是否改变了其与p18的复合物形成，并改变了NF-E2激活红系基因的能力。接下来的一系列实验将检测与NF-E2相互作用的蛋白质，看看这些相互作用是否会改变其功能。这项研究的结果将增加我们对NF-E2功能调控的认识，并确定A-激酶在红细胞成熟过程中的作用。它们还将提供该酶在信号转导中的一般功能的信息。＊＊＊

9506327 Pilz The transcription factor NF-E2 (a complex of two proteins, p45 and p18) binds to specific DNA sequences in the regulatory regions of erythroid genes and appears to be necessary for the transcriptional activation of these genes during red blood cell maturation. The PI has recently found that murine erythroleukemia cells (MEL), a model system of red blood cells, that are deficient in cAMP dependent protein kinase (A kinase), an enzyme involved in signal transduction, are severely impaired in their ability to mature and activate erythroid genes. The also have abnormal binding of NF-E2. Preliminary experiments suggested that A-kinase regulates NF-E2 by phosphorylating p45 and by regulating the complex formation of p45 and p18. The experiments in this grant will test examine this further. The phosphorylation of p45 by A kinase will be studied by determining which amino acids are phosphorylated, to see if this phosphorylation occurs during red blood cell maturation, and determibne if this phosphorylation of p45 changes its its complex formation with p18 and alters the ability of NF-E2 to activate erythroid genes. The next series of experiments will examine proteins which interact with NF-E2 and see if these interactions alter its function. %%% The results of this research will increase our knowledge of the regulation of NF-E2 function and define the role of A- kinase during red blood cell maturation. They will also provide information on the general functions of this enzyme in signal transduction. ***