Topic 8- regulation of transcription Flashcards
What domain use transcription factors?
Eukaryotes
What is the function of transcription factors?
a protein that controls the transcription of genes by binding to a specific region of DNA
What do transcription factors ensure?
genes are being expressed in the correct cells, at the correct time and to the right level
Estimated- 1.____ of human 2.___ code for transcription factors
1.10%
2.genes
What do transcription factors enable organisms to do?
respond to their environment
1.______ types of transcription factors that have 2.____ effects on gene expression
1.several
2.varying
Some 1.______ achieve their 2._____ via transcription factors
1.hormones
2. effect
What does ‘upstream’ refer to?
he DNA before the start of the coding region
What is the promoter region of DNA?
-(In upstream region) the binding site for proteins that control the expression of the genes
Give the 2 proteins which control gene expression
-RNA polymerase
-Transcription factors
Which direction is DNA transcripted and translated in?
Translated= 3-5
Transcribed= 5-3 (to produce mRNA)
How do transcription factors enter the nucleus?
-From cytoplasm
-Through nuclear pores
How are transcription factors activated?
through a signalling pathway that usually starts from outside the cell
Where do transcription factors bind to? what does this binding result in?
-The promoter region of the gene
-Allow or prevent the transcription of the gene from taking place
How do transcription factors interact with RNA polymerase?
-Assist RNA polymerase binding to the gene (stimulate the expression of the gene)
-Preventing it from binding (to inhibit gene expression)
What does the presence of a transcription increase/decrease the rate of?
Rate of transcription of a gene
What is oestrogen?
A steroid hormone found in mammals
What are steroid hormones?
small, hydrophobic, lipid-based hormones that can diffuse through the cell membrane and can pass directly into the nucleus through nuclear pores
What is oestrogen Involved in /responsible for?
-Female fertility cycle
-Stimulation of sperm production in males
What is the first step of the oestrogen stimulation pathway?
Oestrogen diffuses through the cell surface membrane into the cytoplasm
What is the second step of the oestrogen stimulation pathway?
Oestrogen diffuses through a nuclear pore into the nucleus
What is the third step of the oestrogen stimulation pathway?
Within the nucleus, oestrogen attaches to an ERα oestrogen receptor that is held within a protein complex, this causes the ERα oestrogen receptor to undergo a conformational change
What is the 4th step of oestrogen stimulation pathway?
The new shape of the ERα oestrogen receptor allows it to detach from the protein complex and diffuse towards the gene to be expressed
What is the 5th step of oestrogen stimulation pathway?
The ERα oestrogen receptor binds to a cofactor which enables it to bind to the promoter region of the gene, this stimulates RNA polymerase binding and gene transcription
