FoxO1 and FoxA1/2 form a complex on DNA and cooperate to open chromatin at insulin-regulated genes. Biochem Cell Biol 2019 Apr;97(2):118-129
Date
08/25/2018Pubmed ID
30142277DOI
10.1139/bcb-2018-0104Scopus ID
2-s2.0-85063944415 (requires institutional sign-in at Scopus site) 9 CitationsAbstract
We have previously shown that cooperative, interdependent binding by the pioneer factors FoxO1 and FoxA1/2 is required for recruitment of RNA polymerase II and H3K27 acetylation to the promoters of insulin-regulated genes. However, the underlying mechanisms are unknown. In this study, we demonstrate that, in HepG2 cells, FoxO1 and FoxA2 form a complex on DNA that is disrupted by insulin treatment. Insulin-mediated phosphorylation of FoxO1 and FoxA2 does not impair their cooperative binding to mononucleosome particles assembled from the IGFBP1 promoter, indicating that direct disruption of complex formation by phosphorylation is not responsible for the loss of interdependent FoxO1:FoxA1/2 binding following insulin treatment. Since FoxO1 and FoxA1/2 binding is required for the establishment and maintenance of transcriptionally active chromatin at insulin-regulated genes, we hypothesized that cooperative FoxO1 and FoxA1/2 binding dictates the chromatin remodeling events required for the initial activation of these genes. In support of this idea, we demonstrate that FoxO1 and FoxA2 cooperatively open linker histone compacted chromatin templates containing the IGFBP1 promoter. Taken together, these results provide a mechanism for how interdependent FoxO1:FoxA1/2 binding is negatively impacted by insulin and provide a developmental context for cooperative gene activation by these factors.
Author List
Schill D, Nord J, Cirillo LAAuthor
Lisa A. Cirillo PhD Assistant Dean, Associate Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
ChromatinDNA
Forkhead Box Protein O1
Hep G2 Cells
Hepatocyte Nuclear Factor 3-alpha
Hepatocyte Nuclear Factor 3-beta
Humans
Insulin
Insulin-Like Growth Factor Binding Protein 1
Phosphorylation
RNA Polymerase II
Response Elements
