TRANSCRIPTIONAL CONTROL OF HUMAN T CELL RECEPTOR GENES

描述(改编自申请人的摘要)：正常 T淋巴细胞的发育和激活是确保 对病毒和肿瘤病原体的适当宿主反应，以及对 防止对宿主组织的自身免疫破坏。在前四年 R01的年份申请人使用TCRα和β基因作为 用于鉴定和表征转录因子的模型系统 参与调节T细胞的发育和激活。这些研究 已经能够鉴定出几种新的转录因子 似乎在调节T细胞方面发挥重要作用的家族- 特定的基因表达。这些基因包括ETS原癌基因、 GATA锌指蛋白和碱性亮氨酸CREB/ATF家族 拉链转录因子。至少有5种ETS蛋白 T细胞表达：Ets-1、Elf-1、Fli-1、Ets-2和GABPalpha。这个 现有证据表明，淋巴限制因子ETS-1 在调节基因表达方面起着重要作用，如 发育中的胸腺细胞和静息T细胞中的TCRα和β。在……里面 相比之下，Elf-1似乎在调节SET方面发挥了重要作用 激活特异性T细胞基因包括GM-CSF、IL-3、IL-2Rα、 和HIV-2病毒。申请人之前的研究表明，Elf-1是 至少3个翻译后水平：(I)通过激活- DNA结合所需的特异性磷酸化 活性，(Ii)通过与特定的AP1和核因子-kappaB协同结合 转录因子，以及(Iii)通过与转录因子的调节相互作用 视网膜母细胞瘤(RB)基因产物或相关口袋蛋白。因此，精灵1号 似乎代表了激活特异性基因之间的功能联系 T细胞的表达和细胞周期进程。同样，还有 至少6个ATF/CREB蛋白在T细胞中表达。以前的研究 已经提出了这些蛋白质在调节 TCRα和β基因的表达，以及在控制 活化特异性表达的分子，如增殖 细胞核抗原，细胞周期所必需的 T细胞激活后的进展。在中描述的研究中 在这一应用中，建议使用遗传和 用生物化学方法更准确地阐明ETS-1的作用， ELF-1和CREB/ATF转录因子在调节T细胞发育中的作用 和激活。具体来说，它计划(I)阐明 T细胞活化后Elf-1活化的分子基础(II) 在小鼠体内产生靶向干扰Ets-1和Elf-1并研究其 对T细胞发育和激活的影响，以及(Iii)使用转基因 小鼠过表达显性-负性CREB转录 更好地确定CREB/ATF蛋白在调节T细胞中的作用的因子 细胞发育和激活。这些研究应该具有重要的意义 对我们理解ETS和CREB/ATF作用的影响 转录因子在调节T细胞发育和转录中的作用 功能。此外，它们可能有助于阐明分子 基因表达与细胞协同调控机制研究进展 对受体介导的信号事件作出反应的循环进程。

DESCRIPTION (Adapted from the applicant's abstract): The normal development and activation of T lymphocytes are required both to ensure appropriate host responses to viral and neoplastic pathogens, and to prevent autoimmune destruction of host tissues. During the first four years of this R01 the applicant used the TCR alpha and beta genes as model systems to identify and characterize the transcription factors involved in regulating T cell development and activation. These studies have allowed the identification of several novel transcription factor families that appear to play important roles in regulating T cell- specific gene expression. These include the Ets protooncogenes, the GATA zinc finger proteins, and the CREB/ATF family of basic-leucine zipper transcription factors. There are at least 5 Ets proteins expressed in T cells: Ets-1, Elf-1, Fli-1, Ets-2, and GABPalpha. The available evidence suggests that the lymphoid-restricted factor, Ets-1 plays an important role in regulating the expression of genes such as TCR alpha and beta in developing thymocytes and resting T cells. In contrast, Elf-1 appears to play an important role in regulating a set of activation-specific T cell genes including GM-CSF, IL-3, IL-2Ralpha, and HIV-2. The applicant's previous studies have shown that Elf-1 is regulated at at least 3 post-translational levels: (i) by activation- specific phosphorylation, which is required for its DNA binding activity, (ii) by cooperative binding with specific AP1 and NF- kappaB transcription factors, and (iii) by regulated interactions with the retinoblastoma (Rb) gene product or related pocket proteins. Thus, Elf-1 appears to represent a functional link between activation-specific gene expression and cell cycle progression in T cells. Similarly, there are at least 6 ATF/CREB proteins expressed in T cells. Previous studies have suggested important roles for these proteins in regulating the expression of the TCR alpha and beta genes, and in controlling the activation-specific expression of molecules such as the proliferating cell nuclear antigen (PCNA), which is essential for cell cycle progression following T cell activation. In the studies described in this application, it is proposed to use a combination of genetic and biochemical approaches to more precisely elucidate the roles of Ets-1, Elf-1 and CREB/ATF transcription factors in regulating T cell development and activation. Specifically it is planned to (i) elucidate the molecular basis of Elf-1 activation following T cell activation, (ii) produce targeted disruptions of Ets-1 and Elf-1 in mice and study their effects on T cell development and activation, and (iii) use transgenic mice overexpressing a dominant-negative form of the CREB transcription factor to better define the role of CREB/ATF proteins in regulating T cell development and activation. These studies should have important implications regarding our understanding of the role of Ets and CREB/ATF transcription factors in regulating both T cell development and function. In addition, they may help to shed light on the molecular mechanisms involved in coordinately regulating gene expression and cell cycle progression in response to receptor-mediated signaling events.