Role of oestrogen in gene transcription

• Hormones like oestrogen can switch on a gene, and thus start transcription, by combining with a receptor site on the transcriptional factor. This activates the DNA binding site by causing it to change shape.
• Oestrogen is a lipid-soluble molecule and therefore diffuses easily through the phospholipid portion of the cell-surface membrane.
• Once inside the cytoplasm of a cell, oestrogen binds with the site on a receptor molecule on the transcriptional factor. The shape of this site and the shape of the oestrogen molecule complement each another.
• By binding with the site on the receptor of the transcriptional factor, the oestrogen changes the shape of the DNA binding site, which can now bind to DNA.
• Once DNA can bind, the transcriptional factor can now enter the nucleus through a nuclear pore and bind to specific base sequences on DNA. The combination of the transcriptional factor with the DNA stimulates transcription of the gene that makes up the portion of DNA.