MURINE ERYTHROPOIETIN--RESPONSE AND RECEPTORS

重组人促红细胞生成素(Repo)已经问世， 已经开发出红系祖细胞的程序 几个来源的细胞可以获得接近纯度的细胞。我们的 约80%纯小鼠促红细胞生成素受体的初步研究 红系集落形成单位(CFUe)和S8小鼠 红白血病(MEL)细胞株及其侧支循环研究 被其他人感染的小鼠的纯化脾细胞 Friend病毒(FVA)的贫血株，表明有AT 至少两种促红细胞生成素受体(EPOR)：一种带有 离解常数(Kd)约为40 pm，另一种为 Kd约为400 PM受我们不断重复的 观察到红系成熟在病毒中可能是非典型的- 被感染的细胞，我们假设(I)高亲和力 (大约下午40)EPOR要么是病毒输入，要么是 受病毒转化和(Ii)低亲和力调节 (大约下午400)EPOR是自然表达的 鼠标CFUe。我们的目的是验证/证伪这些假设， 同时，回答因以下方面的初步研究而产生的问题 CFUe对EPO的反应及CFUe EPOR生物学研究 和S8-MEL细胞。我们希望借此澄清时间上的 促红细胞生成素加成与珠蛋白基因应答的关系； 解开为什么CFUe-EPOR站点看起来如此丰富的谜团 超越功能需求；建立EPOR可以 受监管；完善我们对身体特征和 EPOR的命运，包括对可能性的确认/拒绝 S8-MEL中EPO和/或EPOR与DNA或染色质结合 细胞；在大型项目中，将亲和力方法应用于 EPOR的分离及其免疫学方法的研究 编码它的重组cDNA克隆；并且，在一个轻快但短暂的- 活生生的事业，分离“早期反应”基因的cdna 表达依赖于EPO，并在此后使用产生的cDNA 用于检查EPO反应的迄今未知方面的克隆 由几个EPOR。

Recombinant human Epo (rEpo) has become available and procedures have been developed whereby erythroid progenitor cells of several provenances can be harvested in near purity. Our preliminary studies of Epo-reception by ca. 80%-pure murine erythroid colony-forming units (CFUe) and by the S8 murine erythroleukemia (MEL) cell line, together with collateral studies by others of purified spleen cells derived from mice infected with the anemia-strain of Friend virus (FVA), indicate that there are at least two kinds of erythropoietin receptors (EpoR): one with a dissociation constant (Kd) of approximately 40 pM, the other with Kd of approximately 400 pM. Conditioned by our repeated observation that erythroid maturation can be atypical in virus- infected cells, we hypothesize that (i) high-affinity (approximately 40 pM) EpoR is either a viral import or one regulated by virus transformation and (ii) low-affinity (approximately 400 pM) EpoR is the one naturally expressed in mouse CFUe. Our intent is to verify/falsify these hypotheses and, concurrently, answer questions arising from preliminary studies of Epo-response by CFUe and from studies of EpoR biology in CFUe and S8-MEL-cells. We hope thereby to clarify the temporal relationship between Epo-addition and globin gene response; resolve the mystery of why CFUe-EpoR sites seem abundant far beyond functional needs; establish some ways in which EpoR can be regulated; refine our understanding of physical features and fate of EpoR, including confirmation/rejection of the possibility that Epo and/or EpoR is bound to DNA or chromatin in S8-MEL cells; in a large-scale undertaking, apply affinity methods to the isolation of EpoR and immunological methods to the isolation of recombinant cDNA clones encoding it; and, in a brisk but short- lived undertaking, isolate cDNA for "early-response" genes whose expression depends upon Epo and, thereafter, use arising cDNA clones to examine heretofore unknown aspects of Epo-responses by the several EpoR.