Previous Article | Next Article ![]()
Mol. Cell. Biol., Feb 1995, 790-795, Vol 15, No. 2
G Zitnik, K Peterson, G Stamatoyannopoulos and T Papayannopoulou
Butyrate and its analogs have been shown to induce fetal hemoglobin in
humans and primates and in erythroid cell cultures. To obtain insights
concerning the cellular mechanisms of butyrate action, we analyzed the
effects of butyrate on human globin gene expression in hybrids produced by
fusing mouse erythroleukemia cells (MEL) with human fetal erythroid cells
(HFE). These hybrids initially express human fetal hemoglobin but
subsequently switch to adult globin expression after several weeks in
culture. We found that alpha-aminobutyric acid, a butyrate analog which
does not induce terminal maturation, strikingly delays the rate of the
gamma- to beta-globin gene (gamma-to-beta) switch in the HFE x MEL hybrids.
The effect of butyrate on globin expression is transient, with the result
that the delay of globin gene switching requires the continuous presence of
this compound in culture. Furthermore, butyrate fails to induce fetal
hemoglobin expression in hybrids which have switched, suggesting that the
effect of this compound on gamma-globin expression is due to inhibition of
gamma gene silencing rather than to induction of gamma gene transcription.
Since in other cellular systems, glucocorticoids antagonize the action of
butyrate, the effect of dexamethasone on the gamma-to-beta switch in HFE x
MEL hybrids was examined. Dexamethasone strikingly accelerated the
gamma-to-beta switch, and its effect was irreversible. The effects of
dexamethasone and butyrate on the gamma-to-beta switch of the HFE x MEL
hybrids appear to be codominant. These results indicate that steroids can
have a direct effect on globin gene switching in erythroid cells.
Copyright © 1995, American Society for Microbiology
Effects of butyrate and glucocorticoids on gamma- to beta-globin gene switching in somatic cell hybrids [published erratum appears in Mol Cell Biol 1995 Jun;15(6):3461]
Department of Medicine, University of Washington, Seattle 98195.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»