Monitoring the Effects of the Oncogenic S250F Mutation on the Intrinsically Disordered C-terminal of FoxA1

Forkhead box protein A1 (FoxA1) belongs to the class of pioneer transcription factors (pTFs) that have the ability to bind and open condensed chromatin and thus establish tissue-specific gene expression. FoxA1 plays a pivotal role for the correct development of various mesoderm derived tissues during embryogenesis and modulates the transcriptional activity of nuclear hormone receptors during adulthood. FoxA1 contains a winged-helix DNA binding domain (DBD) that is flanked by two large intrinsically disordered regions (IDR). The C-terminal IDR is thought to play an important role for the pioneering activity of FoxA1. Mutations in FoxA1 have been strongly correlated with certain cancers, particularly breast cancer. A mutational hotspot found in FoxA1 in breast cancers has been identified in a sub-domain termed Wing 2 that is found on the C-terminal of the DBD. Tumors containing certain Wing2 mutations have shown resistance against endocrine treatments leading to worse survival rate of patients. Therefore, understanding how these mutations can affect the function of FoxA1 and how it can affect the mechanism by which FoxA1 interacts with the nucleosome and could be essential for the development of treatment against hormone therapy resistant breast cancers. In the Wing2 region the S250F mutation is one of the most recurring mutations found in breast cancers and is thought to enhance DNA binding of FoxA1. Still a biophysical characterization of how the mutation affects the function and dynamics of FoxA1 is unclear. In this project FoxA1 containing the S250F mutation was purified and single-molecule FRET measurements conducted to monitor potential changes within the C-terminal, both free in solution and bound to DNA. The data obtained showed that the C-terminal on the mutated FoxA1 behaved differently than on the WT suggesting that the mutation causes the C-terminal to be more compact when free in solution and more extended when bound to DNA. Thus, potentially altering FoxA1´s pioneering activity.

Author dc:creator

• Hafrún Hákonardóttir 1998-

Contributors dc:contributor

• Háskóli Íslands

• Lífefna- og sameindalíffræði
• Stökkbreytingar
• Brjóstakrabbamein
• DNA kjarnsýra

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/1946/48658

OAI identifier oai:identifier

oai:skemman.is:1946/48658