We have located links that may give you full text access.
JOURNAL ARTICLE
RESEARCH SUPPORT, N.I.H., EXTRAMURAL
Early growth response transcription factor EGR-1 regulates Galphaq gene in megakaryocytic cells.
Journal of Thrombosis and Haemostasis : JTH 2006 December
BACKGROUND: Galphaq (Gene GNAQ) plays a major role in platelet signal transduction but little is known regarding its transcriptional regulation.
OBJECTIVES: We studied Galphaq promoter activity using luciferase reporter gene assays in human erythroleukemia (HEL) cells treated with phorbol 12-myristate 13-acetate (PMA) for 24 h to induce megakaryocytic transformation.
METHODS AND RESULTS: PMA-treated HEL cells showed enhanced Galphaq expression. Reporter (luciferase) gene studies on 5' upstream construct (up to -116 bp from ATG) revealed a negative regulatory site at -238/-202 and two positive sites at -203/-138 and -1116/-731. The positive regulatory region -203/-138 contained overlapping Sp1/AP-2/EGR-1 consensus sites. Gel shift studies on Galphaq oligonucleotides 1 (-203/-175) and 2 (-174/-152) using HEL cell extracts demonstrated protein binding that was due to early growth response factor EGR-1 at two sites. Mutations in either EGR-1 site markedly decreased the gene activity, indicating functional relevance. Mutation of consensus E-Box motif (-185/-180) had no effect. Reduction in the expression of endogenous EGR-1 with antisense oligonucleotide to EGR-1 inhibited PMA-induced Galphaq transcription. Correspondingly, Egr-1 deficient mouse platelets also showed approximately 50% reduction in the Galphaq expression relative to wild-type platelets.
CONCLUSIONS: These studies suggest that Galphaq gene is regulated during PMA-induced megakaryocytic differentiation by EGR-1, an early growth response transcription factor that regulates a wide array of genes and plays a major role in diverse activities, including cell proliferation, differentiation and apoptosis, and in vascular response to injury and atherosclerosis.
OBJECTIVES: We studied Galphaq promoter activity using luciferase reporter gene assays in human erythroleukemia (HEL) cells treated with phorbol 12-myristate 13-acetate (PMA) for 24 h to induce megakaryocytic transformation.
METHODS AND RESULTS: PMA-treated HEL cells showed enhanced Galphaq expression. Reporter (luciferase) gene studies on 5' upstream construct (up to -116 bp from ATG) revealed a negative regulatory site at -238/-202 and two positive sites at -203/-138 and -1116/-731. The positive regulatory region -203/-138 contained overlapping Sp1/AP-2/EGR-1 consensus sites. Gel shift studies on Galphaq oligonucleotides 1 (-203/-175) and 2 (-174/-152) using HEL cell extracts demonstrated protein binding that was due to early growth response factor EGR-1 at two sites. Mutations in either EGR-1 site markedly decreased the gene activity, indicating functional relevance. Mutation of consensus E-Box motif (-185/-180) had no effect. Reduction in the expression of endogenous EGR-1 with antisense oligonucleotide to EGR-1 inhibited PMA-induced Galphaq transcription. Correspondingly, Egr-1 deficient mouse platelets also showed approximately 50% reduction in the Galphaq expression relative to wild-type platelets.
CONCLUSIONS: These studies suggest that Galphaq gene is regulated during PMA-induced megakaryocytic differentiation by EGR-1, an early growth response transcription factor that regulates a wide array of genes and plays a major role in diverse activities, including cell proliferation, differentiation and apoptosis, and in vascular response to injury and atherosclerosis.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app