Rapid induction of GATA transcription factors in developing mouse intestine following glucocorticoid administration.
In the developing intestine, transcription of alpha-glucosidase genes such as sucrase-isomaltase and trehalase is stimulated by glucocorticoid administration. The consequent increase of their respective mRNAs is characterized by a 12-h lag, suggesting that the response to glucocorticoids represents a secondary effect. We hypothesized that the primary response of the tissue to glucocorticoids includes induction of one or more intestinal transcription factors. To investigate this hypothesis, we identified a region in the mouse trehalase promoter (located at nucleotides -406 to -377 from the transcription start site) with potential binding sites for three transcription factors: Cdx-2, GATA, and C/EBP. Gel shifts were performed using labeled oligonucleotides from this region with nuclear extracts from jejunums of either control 8-day-old mouse pups or littermates treated with dexamethasone (DEX) 4 h before death. A specific shifted band was observed with DEX extracts but not with control extracts. Supershift assays indicated the presence of GATA-4 and GATA-6 but not GATA-5 nor Cdx-2, C/EBP alpha, C/EBP beta, or C/EBP delta. GATA binding was further implicated by competition studies with mutated oligonucleotides. Finally, Western blot analysis showed GATA-4 and GATA-6 proteins in DEX but not control nuclear extracts. For GATA-4, the same pattern was demonstrated with whole cell extracts and with the cytosol fraction. We conclude that expression of GATA-4 and GATA-6 proteins in the suckling mouse jejunum is stimulated by DEX. This novel finding constitutes an important first step in understanding the molecular mechanism of glucocorticoid action on the developing intestine.
Oesterreicher
Thomas J
TJ
Departmentof Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
Henning
Susan J
SJ
D000818:Animals; D000833:Animals, Suckling / Q000378:metabolism*; D001483:Base Sequence; D017124:Conserved Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D003907:Dexamethasone / Q000494:pharmacology*; D050991:GATA4 Transcription Factor; D050993:GATA6 Transcription Factor; D005938:Glucocorticoids / Q000494:pharmacology*; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D013394:Sucrase-Isomaltase Complex / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis*; D014198:Trehalase / Q000235:genetics
D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; D050993:GATA6 Transcription Factor; C494760:Gata6 protein, mouse; D005938:Glucocorticoids; D014157:Transcription Factors; D003907:Dexamethasone; D013394:Sucrase-Isomaltase Complex; D014198:Trehalase