Unformatted text preview: s (splice junctions),
followed by phosphodiester bond formation between the ends of the
exons. This can occur as one coordinated transfer reaction or as a
sequence of reactions.
Although the breaking of phosphodiester bonds is a common occurrence
in the cell, the formation of phosphodiester bonds between two fragments
of RNA is unique to the RNA splicing process.
RNA splicing can be divided into two principal mechanisms: autocatalytic
and spliceosome-mediated removal of introns from nuclear gene
transcripts (hnRNAs or preRNA).
BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013
BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 30 Spliceosome removal of introns
Spliceosomes assemble in a stepwise
process on the hnRNA prior to splicing.
Splicing of introns in nuclear genes takes
place by transesterification (the
simultaneous cleavage and formation of a
As shown at the rig...
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