Eukaryotic mRNA processing(1-2)
What are ways to reduce degradation while shipping mRNA out of nucleus
-5' cap- 7'-methyl-Gppp placed in reverse 5' end
-3' poly-A tail-10-100 adenosines added to 3' end
Alternative splicing is what
multiple possible mRNA sequence outcomes from single gene based on where mRNA splicing occurs
Eukaryotic Ribosome
40S small subunit
60S large subunit
together make=
80S functional unit
Topic "Ribosomes"
eIF1
prevent large (60S) binding
converting pre-mRNA to mature mRNA
*introns
*exons
eukaryotes used these
what percent of human genes are alternatively spliced
estimated 75%
tRNA must be what
charged
Topic "Amino-acyl transfer RNA"
eIF2
helps initiator tRNA bind 40S
introns start with what?
introns end with what?
start with "GU"
end with "AG"
advantage does not need what?
do not need additional genes
What does a charged tRNA mean and what is it called?
Charged tRNA has the correct amino acid covalently attached to the 3' end of the tRNA and is called "AA-tRNA"
Topic "Amino-acyl transfer RNA"
eIF3
helps assembly of 43S (small subunit)
the "A" in the middle is what and is used for what
is the BRANCHPOINT
this nucleotide is critical for splicing
Disadvantage needs what?
need regulation
1. tRNA & small subunit (40S) bind to mRNA
2. mRNA cap is recognized and bound by small subunit
-facilitated by initiation factors
3. mRNA is "scanned" to find start codon
4. large subunit (60S) binds
eIF4
helps mRNA bind
substrate to make RNA
ATP, CTP, GTP, UTP = NTP
---> added to RNA ( 2 phosphates removed)
---->chop up RNA -----> AMP, CMP, GMP, UMP
RNA processing is only in?
Eukaryotes
Eukaryotes have a specific what?
tRNAiMet
eIF5
prevent large ribosome binding