Gene Expression Flashcards
What regulates gene expression?
proteins (transcriptions factors and co regulators) and miRNA
what is differential mRNA splicing and its significance?
splicing of introns from primary mRNA can occur in many different ways thus mRNA splicing yields in a transcriptome that is much larger than the number of genes in our genome
what is a core promotor?
minimum DNA sequence required for transcription initiation
what are enhancers?
DNA elements that stimulate transcription from a distance
What are silencers?
DNA elements that repress transcription from a distance
What are transcription factors?
proteins that help polyII bind to core promotor and initiate transcription at specific times in specific cell types
Fun facts about transcriptions factors
- main regulators of gene expression and are aided by co factors to modulate transcriptional activity
- bind to promotor or enhancer
- activate or inhibit gene expression
- multiple transcription factors can act in combination
What is a enhancesome ?
multiple enhancers that act in combination on common promotor
What is a CpG island?
proximal promotor elements binding transcription factors like Sp1 to promote initiation of transcription
Hormone receptor, ER, GR, and PR are examples of what?
transcription factors
What are miRNA’s?
short regulatory RNA complementary to other mrNA usually at 3’UTR
What do miRNA’s do?
decrease expression of complimentary mRNA by inhibiting translation or causing degradation of RNA
What are the 2 ways miRNA regulate gene expression?
repress translation
cleave mRNA
What important proteins are involved with the mechanism of miRNA’s?
Drosha & Dicer
How does miRNA control gene expression at the transcriptional level?
binding to promotor region of DNA
What is epigenetics?
heritable changes that are not the result of change of DNA sequence?
What are the mechanisms of epigenetic inheritance?
DNA methylation
histone modification
regulatory non-coding RNA’s (miRNA)
Why is chromatin important?
plays a important role in the regulation of transcription. Gene has to be accessible for it to be transcribed
What are histones?
primary regulatory elements for chromatin structure and gene expression AKA (histones regulate DNA packaging)
What are three ways you can regulate histones?
acetylation, methylation, and phosphorylation
What two enzymes are involved in histone acetylation?
HAT & and HDAC
What happens in histone acetylation?
- charge from amino acid removed
- changes chromatin from a closed state to a open state for transcription.
- increase in gene expression
HDAC’s or histone deacetylases do what?
decrease gene expression
What are sirtuins?
NAD+ dependent HDAC’s
