Splicing, the removal of non-protein coding introns from pre-mRNA, is a critical step
in eukaryotic gene expression that is facilitated by a large, dynamic ribonucleoprotein
complex known as the spliceosome. The spliceosome is composed of five subcomponents of
small nuclear ribonucleoprotein particles consisting of a snRNA and their associated
proteins; these “snRNPs” are referred to as U1, U2, U4, U5, and U6. Recently, the red alga
Cyanidioschyzon merolae was found to be lacking the U1 snRNA, raising questions of
whether U1 proteins are also absent and to what extent the rest of the spliceosome is reduced.
To address this, I computationally searched for known splicing proteins in C. merolae. In
doing so, I found no U1 proteins and a highly reduced spliceosome consisting of 69 splicing
proteins in the organism. ...
