RRC ID 34861
Author Takai H, Matsumura H, Matsui S, Kim KM, Mezawa M, Nakayama Y, Ogata Y.
Title Unliganded estrogen receptor α stimulates bone sialoprotein gene expression.
Journal Gene
Abstract Estrogen is one of the steroid hormones essential for skeletal development. The estrogen receptor (ER) is a transcription factor and a member of the steroid receptor superfamily. There are two different forms of the ER, usually referred to as α and β, each encoded by a separate gene. Hormone-activated ERs form dimers, since the two forms are coexpressed in many cell types. Bone sialoprotein (BSP) is a tissue-specific acidic glycoprotein that is expressed by differentiated osteoblasts, odontoblasts and cementoblasts during the initial formation of mineralized tissue. To determine the molecular basis of the tissue-specific expression of BSP and its regulation by estrogen and the ER, we have analyzed the effects of β-estradiol and ERα on BSP gene transcription. ERα protein levels were increased after ERα overexpression in ROS17/2.8 cells. While BSP mRNA levels were increased by ERα overexpression, the endogenous and overexpressed BSP mRNA levels were not changed by β-estradiol (10(-8)M, 24 h). Luciferase activities of different sized BSP promoter constructs (pLUC3~6) were increased by ERα overexpression, whereas basal and induced luciferase activities by ERα overexpression were not influenced by β-estradiol. Effects of ERα overexpression were abrogated by 2 bp mutations in either the cAMP response element (CRE) or activator protein 1 (AP1)/glucocorticoid response element (GRE). Gel shift analyses showed that ERα overexpression increased binding to the CRE and AP1/GRE elements. Notably, the CRE-protein complexes were disrupted by ERα, CREB and phospho-CREB antibodies. The AP1/GRE-protein complexes were supershifted by the c-Fos antibody. These studies demonstrate that ERα stimulates BSP gene transcription in a ligand-independent manner by targeting the CRE and AP1/GRE elements in the rat BSP gene promoter.
Volume 539(1)
Pages 50-7
Published 2014-4-10
DOI 10.1016/j.gene.2014.01.063
PII S0378-1119(14)00117-6
PMID 24495337
MeSH Animals Bone Development / genetics Bone and Bones Cell Line Cyclic AMP Response Element-Binding Protein / genetics* Cyclic AMP Response Element-Binding Protein / immunology Estradiol / metabolism Estrogen Receptor alpha / biosynthesis Estrogen Receptor alpha / immunology Estrogen Receptor alpha / metabolism* Gene Expression Integrin-Binding Sialoprotein / biosynthesis Integrin-Binding Sialoprotein / genetics* Integrin-Binding Sialoprotein / metabolism Osteoblasts / metabolism* Promoter Regions, Genetic / genetics Proto-Oncogene Proteins c-fos / immunology RNA, Messenger / biosynthesis Rats Regulatory Elements, Transcriptional / genetics Transcription Factor AP-1 / genetics* Transcription Factor AP-1 / immunology Transcription Factor AP-1 / metabolism Transcription, Genetic Transfection
IF 2.984
Times Cited 5
DNA material pLucB (RDB13157) rat BSP pLuc1 (RDB13144) rat BSP pLuc2 (RDB13145) rat BSP pLuc3 (RDB13146) rat BSP pLuc4 (RDB13147) rat BSP pLuc5 (RDB13148) rat BSP pLuc6 (RDB13149) rat BSP pLuc7 (RDB13150) rat BSP pLuc8 (RDB13151) rat BSP pLuc9 (RDB13152) rat BSP pLuc10 (RDB13153) rat BSP pLuc11 (RDB13154) rat BSP pLuc12 (RDB13155) rat BSP pLuc13 (RDB13156).