Gene regulation Flashcards
What is a housekeeping gene?
A housekeeping gene is a gene that all cells express, they are necessary for basic function (metabolism, transcription…)
What is the main way of determining cell type?
Cell type can be determined from looking at regulation of transcription
What it the TATA box?
It is the “eukaryotic promoter”
They control where RNA polymerase begins transcription
What are Enhancers and Silencers? How are they entropically favourable to the gene?
- Enhancers bind activators
- Silencers bind repressors
They are able to act at a great distance, work in either orientation, and can be on either side of the promoter
How do histones affect gene regulation?
Histones inhibit the binding of transcription factors; this means it affects the ability of polymerase to transcribe DNA
What is heterochomatin?
Heterochromatin is tightly wound DNA, it therefore stains darkly, it is transcriptionally inactive and more condense
What is euchromatin?
Lightly stained, less tightly wound
Transcriptionally active and is less condensed
How do XY chromosomes work regulation wise?
A cell always inactivates one of its two X chromosomes, it becomes a barr body.
What is a barr body?
An inactivated chromosome that is condensed into a state that prevents transcription
How can the fur colour of Calico Cats be explained? What is the process they undergo called?
They have different coloured patches;
- they express a different colour based on which X chromosome is active in the gene
This is called lyonization
What are 3 post transcriptional mechanisms of gene regulation?
- Alternative Splicing: When part of the exon is spliced out with the intron
- RNA Stability: A cell has mechanisms for recognizing specific mRNA
- Translation Control: Cells will make RNA that is able to bind to complementary RNA and block its translation
Post translation mechanisms of gene regulation?
- Some proteins are “destroyed on schedule” by a proteosome
- Some proteins of phosphylated by kinases
- Some proteins are selectively degraded
What are Kinases?
Enzymes that phosphylate other proteins
