mRNA Processing

mRNA processing starts in the ________

nucleus

,RNA can be ___________ or ___________

monocistronic, polycistronic

monocistronic mRNA encodes _________ polypeptide chain(s)

one

monocistronic mRNA is found in _________

eukaryotes

polycistronic mRNA encodes __________ polypeptide chain(s)

multiple

polycistronic mRNA is found in _________

prokaryotes

in prokaryotes, mrRNA is ready for translation ____________

immediately

in prokaryotes, transcription and translation are not ____________

separated

in eukaryotes transcription yields ____________

pre-mRNA

pre-mRNA is called a __________ __________

primary transcipt

in eukaryotes, transcription and translation are separated by the ________ ___________

nuclear membrane

three possible RNA modifications:

5' cap, 3' poly-A tail, splicing

All mRNA will have a _____

5' cap

the 5' cap is a _________ ____________ at position ___ on the purine ring

methylated guanine, 7

the cap is added after ___________ of RNA synthesis

initiation

the 5' cap helps with _______ _________

self recognition

the 5' cap helps with ___________ mRNA on the __________ for translation

positioning, ribosome

roles for the 5' tail: ________ __________, ________ ___________, ___________ ________, and _________ ________

self recognition, ribosome positioning, signaling splicing, nuclear pore docking

nuclear pore docking is used in __________ of mRNA from the nucleus

export

all of the protein + the mRNA during export is called the __________

mRNP

mRNP stands for ________ __________ __________ ________

messenger ribonuclear protein complex

mRNP is remodeled by ___________ _________ as it leaves the nucleus

RNA helicase

ribosomes can bind during __________

export

most mRNA get a _______ __________

3' poly-A tail

most addition of poly-A tails occur in the __________

nucleus

only mRNA's for major ___________ lack tails

histones

histones have _______ _________ instead of tails

stem loops

_________ and _________ RNA do not get tails

tRNA, rRNA

tails are usually _________ nucleotides long

200-250

splicing is the removal of ___________ ________

pre-mRNA portions

the protein _________ _________ adds the polyA tail

polyadenylate polymerase

polyadenylate polymerase uses _________ as a substrate

ATP

To get a tail, pre-mRNA must have the sequence ___________ (IMPORTANT)

AAUAAA

to add the poly-A tail, first part of the pre-mRNA needs to be _________

cut

The protein ________ binds to AAUAAA

CPSF

The _________ ___________ ________ (_______) binds to a GU/U sequence

cleavage stimulation factor, CstF

Poly-A tails are added after __________

transcription

after cleavage is complete, _________ uses ATP to add tail

PAP

______ protein helps stabilize the tail while it is being added

PABII

the poly-A tail protects mRNA from a _________ _________

nucleus attack

the poly-A tail aids in __________ __________

ribosome recognition

_______ __________ binds near the cleavage site

cleavage factors

Pre-mRNA’s contain _______ and __________

introns, exons

Introns are sequences that are part of the primary transcript, but not part of the ________ __________

functional mRNA

exons are the _________ or ________ region

coding, expressed

pre-mRNAs and mRNA’s contain a sequence (also called a trailer sequence)

3’UTR

the 3’ UTR may signal the relative ________ of the mRNA

stability

Introns are found in most _________ genes

eukaryotic

Introns are not found in _________

histones

to make a functional mRNA, cells must _______ introns and splice exons

remove

__________ mutations can alter the entire reading frame

splicite

there is always a _______ at the 5’ end of an intron

GU

there is always an ________ at the 3’ end of an intron

AG

a mutation in the end bases results in ______ _________

improper splicing

the splicing process is catalyzed by the _________

spliceosome

the spliceosome is a __________ ______________-

RNA-protein complex

spliceosome is made of __________

snRNP

snRNP’s stand for ________ __________ _____________ _________

small nuclear ribonuclear protein

each snRNP is made up of 1-2 _________

snRNA

5 different snRNA in spliceosomes are _____, _______, ________, _______, ________

U1, U2, U4, U5, U6

Spliceosome assembles on the mRNA precursor during __________

transcription

two steps to splicing ________, ____________

separate exon 1, separate intron and splice exon

to separate the first exon, the adenine in the _______ _________ attacks the ____ guanine

lariat point, 5’

U1 binds to _____

GU

U2 binds to _____ _______

lariat A

U5 forms the _______ _________ with the help of ________ and ____________

lariat loop, U4, U6

the ______ ________ is the key to splicing

branchpoint A

the lariat A will form _______ phosphodiester binds

3 (usually 2)

complexes that explain splicing (there’s seven)

E1 complex, A complex, B complex, bact complex, B* complex, C complex, post-splicing complex

The E1 complex involves _______ snRNP

U1

the E1 complex commits _______ to _________ pathway

pre-mRNA, splicing

A complex involves ___ snRNP

U2

A complex is the ______ and _______ complex

retention, splicing

B complex involves _____, _______, and _______ snRNP

U4, U5, U6

The B complex is the _______ _______

pre-catalytic spliceosome

the B complex evolves into ______, then ________ complex

Bact, B*

the two latter B complex involved ________

prp’s

Bact complex stands for ________ _________-

B activated

Bact includes the ____ _____ _______, _________

intron binding complex, Prp19

In Bact complex, the spliceosome is _______

active

B* complex involves __________

Prp2

Prp2 has ________ activity

ATPase

the B* complex is where the ____ _______ ______ or ________ joins

Exon joining complex, EJC

EJC ________ and _______ the spliced exons

joins, marks

B* is the end of _______ _______ of splicing

step 1

complex C uses ______ to _________ RNA

Prp 16, remodel

the post-splicing complex uses _________ and ___________

Prp22, Prp43

the post-splicing complex _________ the spliceosome

disassemble