Lecture 1 - RNA Gene Regulation Flashcards
(36 cards)
When can gene regulation occur?
at every stage of gene expression
RNA can fold into structures that what?
…that perform diverse biological functions
* for ribosomes its a ribozyme
* gene regulation (trp leader)
etc
What directionality does RNA have?
5’ to 3’ directionality (like DNA)
On the ribose sugar, what is located on the 2’?
a 2’ hydroxyl
What is RNA synthesized as?
a single-stranded polymer
Does RNA stay single-stranded?
No, it forms structures… for example, like the transcription terminator hairpin
What is the ribosome?
it is a ribozyme… ribosomal RNA catalyzes peptide bond formation
What is tRNA?
the adapter for translating the genetic information into a polypeptide
What are tRNA’s processed into?
they are processed into a mature form by a ribozyme called RNase P, which is present in all domains of life
What does the spliceosome do?
it catalyzes RNA splicing… it is also a ribozyme
What is a riboswitch?
they are cis-acting RNA chemical sensors
What small molecules and ions can riboswitches sense?
small molecules: purines, amino acids, vitamins etc.
Ions: flourine, iron, manganese, magnesium
What percentage of bacterial genes are thought to be regulated by riboswitches?
3-5%
Riboswitches can control gene expression at several different levels… Name the levels:
transcription, translation, rna stability and rna splicing
In transcription, what does the riboswitch control?
the riboswitch controls whether a terminator hairpin forms
* more rarely, some riboswitches control rho dependent transcription termination
During translation, what does the riboswitch control?
it controls whether the ribosome can bind a Shine-Dalgarno sequence to initiate translation
In RNA stability, what does the riboswitch control?
controls whether an RNA cleaves itself
*self cleavage causes RNA degradation
During RNA splicing, what does the riboswitch control?
whether RNA splicing occurs
What is the riboswitch aptamer?
a chemical sensor that can bind a ligand
What does the expression platform control?
it controls the gene expression based on whether the aptamer bound to its ligand
* it tells the cell to turn gene expression on or off
Without a ligand, what happens to the structure?
only one structure forms
If the ligand is there what happens to the structure then?
both the structures form
In the absence of a metabolite, the terminator hairpin does what and are the genes expressed or not?
- the terminator hairpin terminates transcription before the downstream genes are transcribed
- the genes are not expressed
Give a real life example of of a riboswitch.
the ZTP riboswitch that controls purine biosynthesis
