Chapter 4- RNA Trancription 2 Flashcards
What does a pre-mrna consist of?
It consists of a 5’ utr and exons and intons and then a 3’ utr.
What is Rna processing
It is the process by which the premrna is made into a mature rna.
What is the first process in rna processing and why
It is the addition of 7 methyl guanosine cap to the 5’ end. This is done to protect the message and serves as a ribosomal binding site.
What is the second process of rna processing and why
Addition of poly a tail to the 3’ end of the mrna after the endonuclease cuts out a bit of 3’ utr that has the signal and the poly a polymerase adds the tail again to protect the message from degradation.
What is the third process of rna processing
It is the spilicing of introns through spilecsomes (made of snrna and proteins) and the neighbouring exons join
Whats the structure of introns when they are removed during splicing
They come out in lariat structure
What is rna editing
A change in the rna transcript sequence without any other method.
What is rna editing useful for
It gives a large variety of proteins with just small number of genes
What does rna editing consist of
It consists of deletion and insertion which happen when grna hybridizes them and endonuclease cleaves and then tutases add or exoses delete and then ligase do the ligation. We also have substituion which is done from c to u by cytodine deaminase and from a to i by adenosine deaminase.
What is an example of rna editing c to u
Apob 100 to apob 100 and 48
What is alternative splicing
It is a method by which alot of proteins can be generated by just a single gene
What are some examples of tropomyosin
Tropomyosin or troponin, lgm or lgd, membrane bound immunoglobin or secreted immunoglobin
What are some clinical scenarios during splicing defects
B thalessimia due to a mutation in the spilicing causing a defective b chain. Then we have sle that is autoimmune with joint aches, depression, anxeity and face rashes that is due to antibodies against the splicosomes itself. Then we have progeria
How are introns in dystrophin gene and in histones
They are less but long in dystrophin gene therefore cover 99% of the gene. They arent even present in eukaryotic histones.
Where is rna editing targetted
Rna editting is targetted as theurapatics in cns disorders.
