BCH5413 L20 - RNA Splicing with Complete Solutions
Splicing - ANSWER-removing all introns & stitching together all exons
RNA splicing mechanism - ANSWER-Chemistry is a RNA-based, Chemistry is a RNA-
based, two transesterifications
1. 2′ -OH of branch site adenine attacks the phosphodiester bond at the 5′ splice site. //
branch pt attachs phosphodiester bond linking 5' splice site btw intron/exon energy-free
reaction, occurs spontaneously to create a loop
2. 2′ -OH of branch site adenine attacks the phosphodiester bond at the 5′ splice site. //
have free OH group at 3' end , which is placed close enough to other phosphodiester
bond, attack to release intron w the tail
first indication that splicing occurs - ANSWER-anneal RNA sequence to a gene (red line
is dsDNA; RNA-DNA duplex - more stable than DNA-DNA), when anneal, can replace
DNA sequence so DNA will form a loop and RNA will bind
--the loop of red DNA represents that something is missing in mature mRNA compared
to the gene that is coding
splice site consensus seq - ANSWER-GUAG
GU ------- A ---15bp---- AG
recognized for splicing, these are most important signals that indicate splice sites; within
the intron
5' splice site - ANSWER-GU
branch point - ANSWER-A
about 20-50bp from 3' splice site but can be much further from 5' splice site
3' splice site - ANSWER-AG
splicing mechanism - ANSWER-
evidence of splicing intermediates - ANSWER-sl7 - gel with intron-exon 2, intron, and
spliced exons over time
--over time, intron & spliced exons accumulate
spliceosome - ANSWER-nuclear complexes responsible for removing intron-derived
sequences from hnRNA, many proteins, Many of these are in the
small nuclear ribonuclear proteins (snRNPs).
Splicing - ANSWER-removing all introns & stitching together all exons
RNA splicing mechanism - ANSWER-Chemistry is a RNA-based, Chemistry is a RNA-
based, two transesterifications
1. 2′ -OH of branch site adenine attacks the phosphodiester bond at the 5′ splice site. //
branch pt attachs phosphodiester bond linking 5' splice site btw intron/exon energy-free
reaction, occurs spontaneously to create a loop
2. 2′ -OH of branch site adenine attacks the phosphodiester bond at the 5′ splice site. //
have free OH group at 3' end , which is placed close enough to other phosphodiester
bond, attack to release intron w the tail
first indication that splicing occurs - ANSWER-anneal RNA sequence to a gene (red line
is dsDNA; RNA-DNA duplex - more stable than DNA-DNA), when anneal, can replace
DNA sequence so DNA will form a loop and RNA will bind
--the loop of red DNA represents that something is missing in mature mRNA compared
to the gene that is coding
splice site consensus seq - ANSWER-GUAG
GU ------- A ---15bp---- AG
recognized for splicing, these are most important signals that indicate splice sites; within
the intron
5' splice site - ANSWER-GU
branch point - ANSWER-A
about 20-50bp from 3' splice site but can be much further from 5' splice site
3' splice site - ANSWER-AG
splicing mechanism - ANSWER-
evidence of splicing intermediates - ANSWER-sl7 - gel with intron-exon 2, intron, and
spliced exons over time
--over time, intron & spliced exons accumulate
spliceosome - ANSWER-nuclear complexes responsible for removing intron-derived
sequences from hnRNA, many proteins, Many of these are in the
small nuclear ribonuclear proteins (snRNPs).
