Non-coding genome Flashcards
What are some examples of noncoding DNA sequences?
Promotors, enhancers, silencers, insulators
Where is a gene’s promoter found?
Upstream of the gene
What is the role of a promoter
Site for binding of molecules, which will then initiate transcription of the gene
What is the role of an enhancer?
Enhance the transcription rate of a gene
What is the end product of non-coding RNA genes?
A functional RNA product
Why is transcriptional control necessary?
Every cell contains every gene, however some cells needs certain genes transcribed more than others, or some genes not transcribed at all
How many types of RNA polymerase are there?
3: I, II, III
What genes does RNA polymerase II transcribe?
All protein coding genes, lncRNA genes,
How many subunits does RNA pol II have?
12
What is recruited to a gene alongside RNA pol II?
General transcription factors and regulatory proteins
What is transcriptional initiation?
The recruitment of RNA pol II and general transcription factors to a gene
How does RNA pol II move along the DNA?
Stepwise
How is the RNA pol II able to unwind the double helix?
One of the general transcription factors has helicase activity
Which DNA strand is used as a template for RNA production?
Antisense
What is elongation in RNA synthesis?
Adding complementary nucleotides to form the RNA strand
What is termination in RNA synthesis?
RNA pol ii stops at the end of a gene and is released from the DNA strand
What is the RNA DNA hybrid region?
The area where the antisense strand of DNA and the RNA strand it is being used as a template for are
What is a cis-regulatory DNA sequence?
A DNA regulatory sequence that is located in the same chromosome as the promoter that they are regulating
What is a trans-regulatory DNA sequence?
A DNA regulatory sequence that is located in a different chromosome as the promoter they are regulating
What is a transcription start site?
A genomic DNA sequence that defines the position where transcription of a gene by RNA pol II begins
Where is the transcription start site typically located in relation to the target gene?
Upstream
How do general transcription factors help RNA pol II?
They position it at the correct location on the genome to initiate transcription
What do transcription start sites contain?
A number of DNA sequence motifs
What (other than GTFs) are required for high levels of accurate transcription from gene promoters?
Additional cis-regulatory sequences such as enhancers or sileners
What is the control region of a gene?
The sequence of DNA that contains all the DNA sequences necessary for its correct expression
Position of control region relative to the gene it controls?
Can be either upstream or downstream of the gene
How can one base sequence that is far upstream/downstream of another regulate/affect the gene?
They may be far apart on the linear DNA sequence, however the linear sequence bends so they may be physically very close to each other.
What is mediator?
A large multi-subunit complex that is needed for the transcription of most genes in the human genome
What do enhancer elements do?
Speed up the rate of RNA pol II-GTF complex assembly in order to promote transcription from a promoter
What can enhancer elements do to chromatin?
Open it
What can silencer elements do to chromatin?
Close it
