Estrogen receptor alpha (ER alpha) and ER beta are members of the steroid nuclear receptor family that modulate gene transcription in an estrogen-dependent manner. ER mRNA and protein have been detected both peripherally and in the central nervous system, with most data having come from the rat. Here we report the development of an ER beta-selective antibody that cross-reacts with mouse, rat, and human ER beta protein and its use to determine the distribution of ER beta in the murine brain. Further, a previously characterized polyclonal antibody to ER alpha was used to compare the distribution of the two receptors in the first comprehensive description of ER distribution specifically in the mouse brain. ER beta immunoreactivity (ir) was primarily localized to cell nuclei within select regions of the brain, including the olfactory bulb, cerebral cortex, septum, preoptic area, bed nucleus of the stria terminalis, amygdala, paraventricular hypothalamic nucleus, thalamus, ventral tegmental area, substantia nigra, dorsal raphe, locus coeruleus, and cerebellum. Extranuclear-ir was detected in several areas, including fibers of the olfactory bulb, CA3 stratum lucidum, and CA1 stratum radiatum of the hippocampus and cerebellum. Although both receptors were generally expressed in a similar distribution through the brain, nuclear ER alpha-ir was the predominant subtype in the hippocampus, preoptic area, and most of the hypothalamus, whereas it was sparse or absent from the cerebral cortex and cerebellum. Collectively, these findings demonstrate the region-selective expression of ER beta and ER alpha in the adult ovariectomized mouse brain. These data provide an anatomical framework for understanding the mechanisms by which estrogen regulates specific neural systems in the mouse.

ATTED-II (http://atted.jp) is a database of gene coexpression in Arabidopsis that can be used to design a wide variety of experiments, including the prioritization of genes for functional identification or for studies of regulatory relationships. Here, we report updates of ATTED-II that focus especially on functionalities for constructing gene networks with regard to the following points: (i) introducing a new measure of gene coexpression to retrieve functionally related genes more accurately, (ii) implementing clickable maps for all gene networks for step-by-step navigation, (iii) applying Google Maps API to create a single map for a large network, (iv) including information about protein–protein interactions, (v) identifying conserved patterns of coexpression and (vi) showing and connecting KEGG pathway information to identify functional modules. With these enhanced functions for gene network representation, ATTED-II can help researchers to clarify the functional and regulatory networks of genes in Arabidopsis.

Publicly available database of co-expressed gene sets would be a valuable tool for a wide variety of experimental designs, including targeting of genes for functional identification or for regulatory investigation. Here, we report the construction of an Arabidopsis thaliana trans-factor and cis-element prediction database (ATTED-II) that provides co-regulated gene relationships based on co-expressed genes deduced from microarray data and the predicted cis elements. ATTED-II () includes the following features: (i) lists and networks of co-expressed genes calculated from 58 publicly available experimental series, which are composed of 1388 GeneChip data in A.thaliana; (ii) prediction of cis-regulatory elements in the 200 bp region upstream of the transcription start site to predict co-regulated genes amongst the co-expressed genes; and (iii) visual representation of expression patterns for individual genes. ATTED-II can thus help researchers to clarify the function and regulation of particular genes and gene networks.

Estrogen replacement increases both the number of dendritic spines and the density of axospinous synapses in the hippocampal CA1 region in young rats, yet this is attenuated in aged rats. The estrogen receptor-␣ (ER-␣) is localized within select spines of CA1 pyramidal cells in young animals and thus may be involved locally in this process. The present study investigated the effects of estrogen on the ultrastructural distribution of ER-␣ in the CA1 of young (3-4 months) and aged (22-23 months) Sprague Dawley rats using postembedding immunogold electron microscopy. Within dendritic spines, most ER-␣ immunoreactivity (IR) was seen in plasmalemmal and cytoplasmic regions of spine heads, with a smaller proportion within 60 nm of the postsynaptic density. In presynaptic terminals, ER-␣-IR was clustered and often associated with synaptic vesicles. Significant effects of both aging and estrogen were observed. Quantitative analysis revealed that nonsynaptic pools of ER-␣-IR within the presynaptic and postsynaptic compartments were decreased (35 and 27%, respectively) in the young estrogen-replaced animals compared with those that received vehicle. Such localized regulation of ER-␣ in response to circulating estrogen levels might directly affect synaptic signaling in CA1 pyramidal cells. No estrogen treatment-related differences were observed in the aged animals. However, 50% fewer spines contained ER-␣ in the aged compared with young hippocampus. These data suggest that the decreased responsiveness of hippocampal synapses to estrogen in aged animals may result from age-related decrements in ER-␣ levels and its subcellular localization vis-à -vis the synapse. Such a role for spinous ER-␣ has important implications for age-related attenuation of estrogen-induced hippocampal plasticity.