PROMONOCYTE RECEPTOR FOR PSG11S

妊娠特异性β 1-糖蛋白（PSG）形成一个非常重要的家族， 与怀孕所必需的血液蛋白密切相关。 尽管 在母体血液中以高水平存在，PSG的作用 是未知的。 然而，降低的血清水平与自发性 堕胎，每300个怀孕中就有一个受到影响。 的 申请人已经证明PSG之一与细胞相互作用， 免疫系统，这表明它可能在修改母体 对抗原性外来胎儿的反应 长期目标是 研究的目的是确定和描述PSG的生物学作用 并探索其在怀孕期间和避孕方面的临床用途。 申请人先前已经表明PSG 11，PSG的一个成员， 与前单核细胞的表面相互作用， 天冬氨酸（RGD）肽基序存在于N-末端结构域的 蛋白 在这项研究中，pSG 11的受体将通过以下方法鉴定： 将放射性标记的含PSG 11 s RGD的肽交联至表面 前单核细胞 受体将通过亲和性分离 通过柱层析法纯化，并测定其部分氨基酸序列。 这 信息将用于分离和表征受体cDNA。 将在多种细胞中检测PSG 11 s受体转录物的表达。 的细胞，使用PCR，和那些表达转录本的细胞将被 测试PSG 11 s结合活性。 使用杆状病毒表达系统，PSG 11 s和相关的PSG 1a将 表达，然后纯化。 这些蛋白质的结合活性 然后将其与PSG 11 s RGD的结合活性进行比较。 含有最初用于表征受体活性的肽。 针对RGD基序和合成竞争肽产生的抗血清， 也将用于更充分地表征结合相互作用。

The pregnancy-specific beta1-glycoprotein (PSG) form a family of very closely related blood proteins which are essential to pregnancy. Despite being present at high levels in the maternal blood, the roles of the PSG are unknown. However, reduced serum levels are associated with spontaneous abortion, a condition that affects 1 in every 300 conceptions. The applicant has demonstrated that one of the PSG interacts with cells of the immune system, suggesting that it may have a role in modifying the maternal response to the antigenically foreign fetus. The long term goal of this research is to identify and characterize the biological roles of the PSG and explore their clinical use, during pregnancy and for contraception. The applicant has shown previously that PSG11s, one member of the PSG, interacts with the surface of promonocyte cells via an arginine-glycine- aspartate (RGD) peptide motif present in the N-terminal domain of the protein. In this study, the receptor for pSG11s will be identified by cross-linking a radiolabeled PSG11s RGD-containing peptide to the surface of promonocyte cells. The receptor will be isolated by affinity chromatography and parts of its amino acid sequence determined. This information will be used to isolate and characterize the receptor cDNA. Expression of the PSG11s receptor transcript will be examined, in a variety of cells, using PCR, and those cells expressing the transcript will be tested for the PSG11s binding activity. Using a baculovirus expression system, PSG11s and the related PSG1a, will be expressed and then purified. The binding activity of these proteins will then be compared with the binding activity of the PSG11s RGD- containing peptide initially used to characterize the receptor activity. Antisera raised against the RGD motif, and synthetic competitor peptides, will also be used to characterize the binding interaction more fully.