Narrative abstract This case-control study evaluated the effect of hysteroscopically identified endometrial polyps on endometrium using HOXA10 and HOX11, known molecular markers of endometrial receptivity. Uteri with endometrial polyps demonstrated a marked decrease in HOXA10 and HOXA11mRNA levels that may impair implantation; these findings suggest a molecular mechanism to support clinical findings of diminished pregnancy rates in women with endometrial polyps.

We have simulated the interaction of L-thyroxine (l), D-thyroxine (2), and their deamino (3) and decarboxy (4) analogues with the human plasma protein prealbumin by using molecular mechanics calculations. Starting geometries were taken from the high-resolution X-ray structure of prealbumin and difference electron density maps of the prealbumin-thyroxine complex. We model the interactions by using the atoms of the thyroxine analogue and approximately 250 atoms within the binding site of prealbumin, minimizing the total energy with respect to all geometric degrees of freedom. Using the molecular mechanics calculated interaction energies and a simple empirical method to estimate the solvation energy differences of 1-4, we qualitatively reproduce the experimentally observed relative free energies of association of these analogues to prealbumin and offer a structural and energetic model to account for the different binding affinities of analogues 1-4 to the protein.

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Computer graphics modeling of the thyroxine-prealbumin complex provides a detailed picture of the interactions between thyroxine and prealbumin. A wide variety of thyroid hormone analogue-prealbumin complexes were modeled by calculating the molecular surfaces of the analogues and the prealbumin hormone-binding site. Analogues with high binding affinity were observed to fill more of the hormone-binding site than low-affinity analogues. These surface models described many aspects of the hormone-protein interaction which were not obvious using simple wire models and led us to develop a model which accounts for thyroid hormone-prealbumin structure-activity relationships and ultimately to predict and measure the relative binding affinities of four previously untested thyroid hormone analogues to prealbumin.

7028nm ( E 14); nmr (Dz0) 8.55 (s, 1 H), 4.18 (t, 2 H), 3.63 (singlet methyl superimposed on multiplet, 4 H), 1.7-2.8 (m, 2 H), 1.33 (d, 3 H); tlc [Iz detection, EtOH-0.1 N HCl, 2:1] one spot, Rf 0.43; tlc [Iz detection, rz-BuOH-HOAc-HzO, 4: 1 :5] one spot, Rf 0.31 after two elutions; mass spectrum (70 eV) m/e (re1 intensity) 97 (54, M+ -HCl), 96 (loo), 82 (34). Molecular Formula: Calcdfor C6H11N(Mt -HC1): 97.0891. Found: 97.0887. 1,3,3-Trimethyl-2-pyrr0lidinone-3,3-d~mer~~l-~~C (18).To 500 ml of anhydrous diethyl ether and 220 mmole (31 ml) of diisopropylamine (freshly distilled from BaO), cooled to -70", was added 131 ml (210 mmol) of rz-butyllithium (1.6 M in hexane). Then 4.95 g (50 mmol; 4.85 ml) of 1-methyl-2-pyrrolidinone was added, the solution was stirred for 15 min at -70", and 13.8 ml (220 mmol) of CH31-*4C* was added. Stirring was continued at room temperature for 16 hr, 150 ml of HzO was added, the ether layer was removed and evaporated in DUCUO, and the residue was dissolved in 100 ml of HzO. The combined aqueous solutions were continuously extracted with methylene chloride for 24 hr. Removal of the solvent and distillation of the residue at 95-97" (27 mm) gave 4.79 g (78z) of 18: nmr (CDCl8) 3.29 (t, 2 H), 2.79 (s, 3 H), 1.81 (t, 2 H), 1.04 (s, 6 H); glpc on 30% QF-1 on Chromosorb P (168'; 100 ml/min; 10 ft X 0.25 in.) one peak, 9.0 min. Arid. ,3-dimethylpyrrolidine (17). To 6 mmol of 1,3dimethyl-1-pyrrolinium chloride and 6 ml of HzO were added 35 ml of 1 N NaOH, 10 ml of HzO, 20 ml of ethanol, and 15 ml of ethyl acetoacetate. After stirring in the dark under nitrogen for 17 days, 50 ml of concentrated HCl was added. The reaction mixture was warmed on a steam bath for 5 hr, and concentrated to 5 ml in DUCUO. The residue was dissolved in 50 ml of water and made strongly alkaline with 6 N NaOH; the resulting aqueous solution was continuously extracted with methylene chloride for 4 days. Removal of the solvent gave 440 mg (47%) of 17: ir (thin film) 1730 cm-1 ( e o ) ; nmr (CDClJ 2.7-3.7 (m, 5 H), 2.69 (s, 3 H), 1.4-2.5 (m, 3 H), 2.30 (s, 3 H), 1.12 (d, 3 H); mass spectrum (70 eV) m/e (re1 intensity ) 155 (4, MT), 140 (2), 124 (28), 109 (21), 98 (100). Warming 17 with a saturated ethanolic solution of picric acid gave the picrate which was recrystallized from absolute ethanol: mp 147-151 dec; nmr (pyridine-db) 8.97 (s, 2 H), 3.Abstract: Some stable free radical analogs of histidine have been prepared which contain a nitronyl nitroxide ring system in place of the imidazole function. The esr spectra of these amino acids show magnetically nonequivalent methylene protons as shown by different hyperfine coupling constants of the P-methylene hydrogens. The 18) T. Kawamura.

The cis-regulatory element localized to position -292/-285 of the mouse GnRH receptor (mGnRHR) gene promoter, designated Sequence Underlying Responsiveness to GnRH 1 (SURG-1), has been shown previously to contribute to stimulation of mGnRHR gene expression by GnRH. We have identified three specific protein-DNA complexes on the SURG-1 element by EMSA using nuclear extracts from the gonadotrope-derived alphaT3-1 and LbetaT2 cell lines. Serial mutagenesis and supershift assays identified nuclear factor Y (NF-Y) binding to -288/-284 and Oct-1 binding to a TAAT sequence at -290/-287. Binding of these two transcription factors was confirmed in vivo by chromatin immunoprecipitation assay and increased in response to GnRH stimulation. To define the functional significance of these sequences in the regulation of mGnRHR gene transcription, transient transfection assays were performed in alphaT3-1 cells using a 1.2-kb mGnRHR (-1164/+62) gene promoter-luciferase reporter construct with selective mutations of the Oct-1, NF-Y, and/or the previously characterized activating protein 1 (AP-1) binding site (-274/-268). Individual mutations in the Oct-1, NF-Y, and AP-1 sites decreased both basal expression and stimulation by GnRH agonist, and the combined mutation of the Oct-1 and AP-1 binding sites further reduced basal transcriptional activity and abolished GnRH stimulation. Overexpression of NF-YA increased GnRHR promoter activity, whereas expression of a dominant negative NF-YA mutant decreased activity, further supporting a role of NF-Y in regulation of mGnRHR gene transcription. In addition, knockdown of Oct-1 by small interfering RNA confirmed that Oct-1 is important for mGnRHR gene expression. In conclusion, NF-Y and Oct-1 bind to the SURG-1 element to direct basal and GnRH-stimulated expression of the mGnRHR gene.

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