Estrogen Receptor Beta (ERβ) and Liver Receptor Homolog-1 (LRH-1) are two nuclear receptors and ligand-activated transcription factors. To explore their interaction with each other and investigate whether they can bind to DNA in the same protein complex, human cell-lines expressing ERβ were modified to express LRH-1 with a Myc-tag by transfection of a pcDNA plasmid. Co-Immunoprecipitation (Co-IP) was performed on the cell lysate to pull-down complexes containing LRH-1 followed by detection of ERβ using Western Blot to determine if ERβ exists in the same complexes as LRH-1. The Western Blot analysis gave a band corresponding to ERβ, suggesting that ERβ and LRH-1 exist in the same complex and can bind DNA together. The band seen was faint compared to the positive control, which could indicate that the interaction is weak in human cells or poor pull-down.

Even though the results indicate that ERβ and LRH-1 bind to DNA in the same complex, further research is needed to confirm this finding and determine the nature of their interaction. Competitive binding between ERβ and LRH-1 cannot be excluded by this study. More detailed studies can give insight into how these transcription factors help regulate gene expression and further our understanding of their role in ovarian dysfunctions and ovarian cancer in granulosa cells.

For further studies we propose Hi-C sequencing, which can provide more information on the spatial interaction between ERB and LRH-1, for example whether the binding of ERß to chromatin-bound LRH-1 enables chromatin loop formation. We also propose reporter transactivation assays to find how LRH-1 and ERß affect gene expression together, and investigate the presence of eventual competitive binding.