regulating transcription

what is a transcription factor ?

proteins which travel inot the nucleus & controls the rate of transcription by either activating or repressing RNA polymerase

what is the promotor region ?

binding site of RNA polymerase & therefore is starting point for transcription of the gene

how do transcription factors bind to genes and anable transcription ?

• TF bind to the promotor region & assists the RNA polymerase binding →allowing transcription to occur

how do transcription factors help silence genes ?

• TF binds to the promotor region & prevent RNA polymerase from binding → no transcription occurs

how are transcription factors regulated ?

• TFs can be switched on/ off by an inhibitor molecule

• inhibitor molecules can bind to TF, preventing it from attaching to the promotor region

• if the TF is an activator, the gene may not be expressed

• if the TF is a repressor, the gene may not be silenced

how does oestrogen act as a trancription factor ?

1. oestrogen crosses cell surface membrane

2. TF binds to a TF, forming a homone receptor complex (not all cells have receptor proteins so not all affected)

3. hormoone receptor complex moves from cytoplasm into the nucleus via the nuclear pore

4. the complex binds to the promotor region of the gene, activating/ repressing the transcription

5. the gene is translated, creating new protein molecuels