BIMM 100 – FINAL questions n
answers rated
RNA Splicing
What are the 3 consensus sequences within pre-RNA necessary for correct splicing? - correct
answer ✔✔ 1. 5' splice site GU begins most introns
2. 3' splice site AG ends most introns
3. Branch point in middle with a conserved A residue (followed by pyrimidine tract of U&C)
Spliceosome - correct answer ✔✔ - consist of hundreds of proteins complexed with 5 different
small nuclear ribonucleoprotein particles (snRNP): U1, U2, U4, U5, U6
- U1: binds to 5' splice site (GU)
- U2: binds to branch point
- U6: binds to 5' splice site at a later point
- SM (smith) and SML (smith like proteins) are important for the proper functioning and
assembly of snRN.
- SM named after patient named Smith with lupus who had antibodies attacking SM protein
Splicing Factors - correct answer ✔✔ modulate the ability of spliceosomes to recognize or
choose the splice sites
- SR Proteins:
+RRM (RNA recognition domain): binds specific RNA regions
+RS (Arg/Ser) domain: binds to other proteins
- BBP (Branching binding protein): binds to branch point
, - U2AF (U2 auxiliary factors): binds to pyrimidine tract/3' splice site
Alternative splicing - correct answer ✔✔ -different combinations of exons through multiple 3'
cleavage sites
- calcitonin vs CGRP
they both come from same gene but just alternatively spliced!
-its tissue specific:
1. splice in thyroid makes calcitonin leading to calcium homeostasis
2. splice in brain makes CGRP leading to vasodilation and pain signals -> migraines
CaMKIIδ alternative splicing - correct answer ✔✔ -splicing at δA targets the membrane
-splicing at δB targets the nucleus (which contains NLS, nuclear localization sequence)
-splicing at δC targets the cytoplasm
CARDIAC DYSFUNCTION:
-excess δC -> excess release Ca2+ from SR -> problems with cardiac muscle contraction
(arrhythmias and heart failure)
**addition of exon 15&16
excess δB -> inactivates HDAC -> increase binding of cardiac transcription factors (MEF2&SRF) ->
over expression of cardiac proteins -> heart hypertrophy
**addition of exon 14
alternative splicing: sex determination in fruit flies - correct answer ✔✔ -sex determined by
ratio of x chromosome to autosomal chromosomes
- if no make Sxl -> no make Tra -> express Dsx Male (x:a; 1:2 lower x ratio)
answers rated
RNA Splicing
What are the 3 consensus sequences within pre-RNA necessary for correct splicing? - correct
answer ✔✔ 1. 5' splice site GU begins most introns
2. 3' splice site AG ends most introns
3. Branch point in middle with a conserved A residue (followed by pyrimidine tract of U&C)
Spliceosome - correct answer ✔✔ - consist of hundreds of proteins complexed with 5 different
small nuclear ribonucleoprotein particles (snRNP): U1, U2, U4, U5, U6
- U1: binds to 5' splice site (GU)
- U2: binds to branch point
- U6: binds to 5' splice site at a later point
- SM (smith) and SML (smith like proteins) are important for the proper functioning and
assembly of snRN.
- SM named after patient named Smith with lupus who had antibodies attacking SM protein
Splicing Factors - correct answer ✔✔ modulate the ability of spliceosomes to recognize or
choose the splice sites
- SR Proteins:
+RRM (RNA recognition domain): binds specific RNA regions
+RS (Arg/Ser) domain: binds to other proteins
- BBP (Branching binding protein): binds to branch point
, - U2AF (U2 auxiliary factors): binds to pyrimidine tract/3' splice site
Alternative splicing - correct answer ✔✔ -different combinations of exons through multiple 3'
cleavage sites
- calcitonin vs CGRP
they both come from same gene but just alternatively spliced!
-its tissue specific:
1. splice in thyroid makes calcitonin leading to calcium homeostasis
2. splice in brain makes CGRP leading to vasodilation and pain signals -> migraines
CaMKIIδ alternative splicing - correct answer ✔✔ -splicing at δA targets the membrane
-splicing at δB targets the nucleus (which contains NLS, nuclear localization sequence)
-splicing at δC targets the cytoplasm
CARDIAC DYSFUNCTION:
-excess δC -> excess release Ca2+ from SR -> problems with cardiac muscle contraction
(arrhythmias and heart failure)
**addition of exon 15&16
excess δB -> inactivates HDAC -> increase binding of cardiac transcription factors (MEF2&SRF) ->
over expression of cardiac proteins -> heart hypertrophy
**addition of exon 14
alternative splicing: sex determination in fruit flies - correct answer ✔✔ -sex determined by
ratio of x chromosome to autosomal chromosomes
- if no make Sxl -> no make Tra -> express Dsx Male (x:a; 1:2 lower x ratio)
