5.4 Regulation of Transcription Part 4 Flashcards
Which RNA polymerases are need all the time and which is under extreme control?
RNA poly I and III are needed all of the time
RNA poly II is under control
What are the ways that RNA poly II is regulated?
- core promoter designates transcription start site
- cis-acting elements that change the expression of genes
What are examples of cis-acting elements that help regulate RNA poly II?
silencers
enhances
What do silencers do?
help turn off the expression of genes
What do enhancers do?
help turn on the expression of genes
Where can cis-acting elements be located?
anywhere in relation to the gene
What are transcription factors?
trans-acting elements
What are the categories of transcription factors?
general transcription factors
transcriptional activators
transcriptional repressors
What are general transcriptional factors?
critical for all RNA poly II transcription; required for binding of RNA poly II to the promoter site
What are activators and repressors?
bind to silencers and enhancers to either help prevent the assembly of RNA initiation complexes and help RNA poly II to dissociate from RNA to allow transcriptional elongation
What is the primary transcript also known as?
pre-RNA
What is the RNA known as that actually makes the proteins?
mature mRNA
What are introns?
noncoding nucleotide sequences in the primary transcript
How do we make mature RNA?
remove introns
What are the sequences left in the mature mRNA to be encoded?
exons
