The mechanism by which the estrogen receptor and other steroid hormone receptors regulate gene expression in eukaryotic cells is not well understood. In this study, a complementary DNA clone containing the entire translated portion of the messenger RNA for the estrogen receptor from MCF-7 human breast cancer cells was sequenced and then expressed in Chinese hamster ovary (CHO-K1) cells to give a functional protein. An open reading frame of 1785 nucleotides in the complementary DNA corresponded to a polypeptide of 595 amino acids and a molecular weight of 66,200, which is in good agreement with published molecular weight values of 65,000 to 70,000 for the estrogen receptor. Homogenates of transformed Chinese hamster ovary cells containing a protein that bound [3H]estradiol and sedimented as a 4S complex in salt-containing sucrose gradients and as an 8 to 9S complex in the absence of salt. Interaction of this receptor-[3H]estradiol complex with a monoclonal antibody that is specific for primate ER confirms the identity of the expressed complementary DNA as human estrogen receptor. Amino acid sequence comparisons revealed significant regional homology among the human estrogen receptor, the human glucocorticoid receptor, and the putative v-erbA oncogene product. This suggests that steroid receptor genes and the avian erythroblastosis viral oncogene are derived from a common primordial gene. The homologous region, which is rich in cysteine, lysine, and arginine, may represent the DNA-binding domain of these proteins.

Neuropeptide Y (NPY) is one of the most abundant neuropeptides in the mammalian nervous system and exhibits a diverse range of important physiological activities, including effects on psychomotor activity, food intake, regulation of central endocrine secretion, and potent vasoactive effects on the cardiovascular system. Two major subtypes of NPY receptor (Y1 and Y2) have been defined by pharmaclgical criteria. We report here the molecular cloning of a cDNA sequence encoding a human NPY receptor and the corrected sequence for a rat homologue. Analysis ofthis sequence confirms that the receptor is a member of the G protein-coupled receptor superfamily. When expressed in Chinese hamster ovary (CHO) or human embryonic kidney (293) cells, the receptor exhibits the characteristic ligand specificity of a Y1 type of NPY receptor. In the 293 cell line, the receptor is coupled to a pertussis toxinsensitive G protein that mediates the inhibition of cyclic AMP accumulation. In the CHO cell line, the receptor is coupled not to the inhibition of adenylate cyclase but rather to the elevation of intraceflular calcium. These results demonstrate that second messenger coupling of the NPY-Y1 receptor is cell type specific, depending on the specific repertoire of G proteins and effector systems present in any cell type.Neuropeptide Y (NPY), a 36-amino acid peptide, is an important regulator in both the central and peripheral nervous systems (1). NPY is highly conserved in primary structure between species, as the sequences of human, rat, rabbit, and guinea pig are identical and differ from the porcine sequence by only a single amino acid (2). NPY also shares close sequence homology and a common tertiary structure with a family of peptides which include peptide YY (PYY) and pancreatic polypeptide (PP) This G protein complex in turn activates a variety of second messenger systems, including a decrease in cyclic AMP and an increase in intracellular calcium (10). However, there are reports of NPY receptors coupled to phosphoinositol metabolism, suggesting the existence ofadditional receptor subtypes and/or multiple functions for the Y1 and Y2 subtypes (6, 11).We report here the molecular cloning of a cDNA sequence encoding a human NPY receptor,* which exhibits the characteristic ligand specificity of a Y1 receptor. When expressed in different cell lines, the receptor couples via pertussis toxin-sensitive G proteins to different second messenger systems.MATERIAL AND METHODS Nucleotide Sequence Determination. Total RNA (3 pug) from rat brain was used as a template to synthesize random primed single-stranded cDNA. The cDNA was used in a polymerase chain reaction (PCR) together with the oligonucleotide primers, which correspond to positions 672-584 and 48-78 in the rat cDNA clone FC5 (12). PCR conditions: 30 cycles at 950C for 1 min, 630C for 2 min, and 720C for 1 min. The reaction product was digested with EcoRI and Pst I, gel purified, and subcloned for sequencing in the Bluescript vector (Stratagene) for confirmation of the seq...

The neuropeptide Y (NPY) system has been implicated in the regulation of bone homeostasis and osteoblast activity, but the mechanism behind this is unclear. Here we show that Y1 receptor signaling is directly involved in the differentiation of mesenchymal progenitor cells isolated from bone tissue, as well as the activity of mature osteoblasts. Importantly, the mRNA levels of two key osteogenic transcription factors, runx2 and osterix, as well as the adipogenic transcription factor PPAR-g, were increased in long bones of Y1 À/À mice compared with wild-type mice. In vitro, bone marrow stromal cells (BMSCs) isolated from Y1 À/À mice formed a greater number of mineralized nodules under osteogenic conditions and a greater number of adipocytes under adipogenic conditions than controls. In addition, both the number and size of fibroblast colony-forming units formed in vitro by purified osteoprogenitor cells were increased in the absence of the Y1 receptors, suggestive of enhanced proliferation and osteogenesis. Furthermore, the ability of two specific populations of mesenchymal progenitor cells isolated from bone tissue, an immature mesenchymal stem cell population and a more committed osteoprogenitor cell population, to differentiate into osteoblasts and adipocytes in vitro was enhanced in the absence of Y1 receptor signaling. Finally, Y1 receptor deletion also enhanced the mineral-producing ability of mature osteoblasts, as shown by increased in vitro mineralization by BMSCs isolated from osteoblast-specific Y1 À/À mice. Together these data demonstrate that the NPY system, via the Y1 receptor, directly inhibits the differentiation of mesenchymal progenitor cells as well as the activity of mature osteoblasts, constituting a likely mechanism for the high-bone-mass phenotype evident in Y1 À/À mice. ß

The human eosinophil differentiation factor (EDF) gene was cloned from a genomic library in A phage EMBL3A by using a murine EDF cDNA clone as a probe. The DNA sequence of a 3.2-kilobase BamHI fragment spanning the gene was determined. The gene contains three introns. The predicted amino acid sequence of 134 amino acids is identical with that recently reported for human interleukin 5 but shows no significant homology with other known hemopoietic growth regulators. The amino acid sequence shows strong homology (-70% identity) with that of murine EDF. Recombinant