Embryonic stem cells and embryonal carcinoma P19 cells produce erythropoietin (Epo) in an oxygen-independent manner, although lactate dehydrogenase A (LDHA) is hypoxia-inducible. To explore this paradox, we studied the operation of cis-acting sequences from these genes in P19 and Hep3B cells. The Epo gene promoter and 3′ enhancer from P19 cells conveyed hypoxia-inducible responses in Hep3B cells but not in P19 cells. Together with DNA sequencing and the normal transcription start site of P19 Epo gene, this excluded the possibility that the noninducibility of Epo gene in P19 cells was due to mutation in these sequences or unusual initiation of transcription. In contrast, reporter constructs containing LDHA enhancer and promoter were hypoxia inducible in P19 and Hep3B cells, and mutation of a hypoxia- inducible factor 1 (HIF-1) binding site abolished the hypoxic inducibility in both cells, indicating that HIF-1 activation operates normally in P19 cells. Neither forced expression of hepatocyte nuclear factor 4 in P19 cells nor deletion of its binding site from the Epo enhancer was effective in restoring Epo enhancer function. P19 cells may lack an unidentified regulator(s) required for interaction of the Epo enhancer with Epo and LDHA promoters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.