Estradiol regulates alternative splicing of estrogen receptor-alpha mRNA in differentiated NG108-15 neuronal cells.
The biological actions of estrogen are mostly conveyed through interaction with two different types of estrogen receptor (ER), ER-alpha and ER-beta. With regard to ER-alpha, an alternatively spliced form and its translated product, truncated estrogen receptor product-1 (TERP-1), have been identified in the rat pituitary. TERP-1 has the ability to inhibit the ER binding to DNA response element by forming hetero-dimers with the wild-type ER. Furthermore, TERP-1 expression increased concurrently with serum estrogen levels. Although estrogen also plays important roles in the central nervous system, the existence and regulatory mechanism of alternatively spliced ER-alpha mRNA expression has remained unclear. The present study evaluated the expression of the alternatively spliced form of the ER-alpha gene, and examined the influence of a representative ER ligand, 17beta-estradiol (E2), on the expression in differentiated NG108-15 neuronal cells. A real-time RT-PCR analysis using primer sets designed to amplify from exons 3 to 4, exons 4 to 5, exons 5 to 6, exons 6 to 7, and exons 7 to 8 of the mouse ER-alpha gene revealed the existence of alternatively spliced ER-alpha mRNA and its putative transcription initiation site, located between exon 4 and exon 5. Although E2 had no apparent effect on the overall expression of ER-alpha mRNA, it reduced the incidence of the alternatively spliced form of ER-alpha. The down-regulation by E2 predominantly arose via binding to nuclear ERs. The present study demonstrated that alternatively spliced ER-alpha mRNA is expressed in differentiated NG108-15 neuronal cells, and provides evidence for the functional up-regulation of ER-alpha via the ligand-binding activation of ERs.
Aizawa
Shu
S
Department of Animal Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-8510, Japan.
Yamamuro
Yutaka
Y
D017398:Alternative Splicing / Q000187:drug effects*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000235:genetics*; D008024:Ligands; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011960:Receptors, Estrogen / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D047628:Estrogen Receptor alpha; D008024:Ligands; D012333:RNA, Messenger; D011960:Receptors, Estrogen; C118565:TERP-1; D004958:Estradiol