Sudo Satoko, Avsian-Kretchmer Orna, Wang Lora Shuo, Hsueh Aaron J W
Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, California 94305-5317, USA.
J Biol Chem. 2004 May 28;279(22):23134-41. doi: 10.1074/jbc.M402376200. Epub 2004 Mar 23.
Bone morphogenetic proteins (BMPs) are important for body patterning and morphogenesis, whereas several BMP antagonists regulate the functions of BMPs during embryonic development and tissue differentiation. Protein related to DAN and cerberus (PRDC) is a secreted protein with a cystine knot structure identified by gene trapping in embryonic stem cells. Although PRDC shows sequence homology with proteins of the BMP antagonist family, its biological activity and physiological functions are unclear. We generated recombinant PRDC and its paralog, gremlin, and tested their ability to suppress actions initiated by diverse BMP proteins. Similar to the known BMP antagonist, gremlin, PRDC blocked ligand signaling induced by BMP2 and BMP4 but had minimal effects on reporter gene activation induced by GDF-9, activin, or transforming growth factor-beta. Co-precipitation assays further demonstrated the direct protein-protein interactions between PRDC and BMP2 or BMP4. Reverse transcriptase-PCR analyses indicated that PRDC transcripts are widely expressed showing higher levels in ovary, brain, and spleen. In mouse ovary, PRDC transcripts were increased following gonadotropin treatment. In situ hybridization analyses further indicated that ovarian PRDC transcripts are localized in granulosa cells of selective follicles. In addition, co-treatment with PRDC antagonized the inhibitory effects of BMP4 on the follicle-stimulating hormone stimulation of progesterone production by cultured rat granulosa cells. Thus, PRDC is a potent BMP antagonist with a wide tissue expression pattern, and ovarian PRDC expressed in granulosa cells could be involved in follicular development by antagonizing the actions of theca cell-derived BMPs.
骨形态发生蛋白（BMPs）对身体模式形成和形态发生很重要，而几种BMP拮抗剂在胚胎发育和组织分化过程中调节BMPs的功能。与DAN和Cerberus相关的蛋白（PRDC）是一种通过胚胎干细胞基因捕获鉴定出的具有胱氨酸结结构的分泌蛋白。尽管PRDC与BMP拮抗剂家族的蛋白具有序列同源性，但其生物学活性和生理功能尚不清楚。我们制备了重组PRDC及其旁系同源物gremlin，并测试了它们抑制多种BMP蛋白引发作用的能力。与已知的BMP拮抗剂gremlin相似，PRDC阻断了BMP2和BMP4诱导的配体信号传导，但对GDF-9、激活素或转化生长因子-β诱导的报告基因激活影响极小。共沉淀分析进一步证明了PRDC与BMP2或BMP4之间存在直接的蛋白质-蛋白质相互作用。逆转录酶-PCR分析表明，PRDC转录本广泛表达，在卵巢、脑和脾脏中表达水平较高。在小鼠卵巢中，促性腺激素处理后PRDC转录本增加。原位杂交分析进一步表明，卵巢PRDC转录本定位于选择性卵泡的颗粒细胞中。此外，PRDC共同处理可拮抗BMP4对培养的大鼠颗粒细胞中促卵泡激素刺激孕酮产生的抑制作用。因此，PRDC是一种具有广泛组织表达模式的强效BMP拮抗剂，在颗粒细胞中表达的卵巢PRDC可能通过拮抗卵泡膜细胞来源的BMPs的作用参与卵泡发育。
