Three SR subfamily proteins were found in Physcomitrella patens; PpSR40, PpSr36 and PpSR39. These three proteins consist of two RRM regions, located in the 5' end and in the middle of the protein, and one SR region in the 3' end.

A phylogenetic analyze showed that the three proteins are a product of two gene duplications after the moss separation. A) Neighbor joining analysis on protein level B) Maximum likelihood analysis on protein level C) Neighbor joining analysis on RRM level D) Maximum likelihood analysis on RRM level

The expression analysis show that different types of stress affect gene expression of the SR genes differently. This suggests that some SR-proteins may have very specialized function but that there also can be a functional overlap. Similar expression patterns have also been shown in Arabidopsis thaliana and Oryza sativa.
 

In addition to differential gene expression, a change in the splicing patterns were seen in PpSR40 and PpSR36.  One AS product was seen for PpSR40 after exposure of NaCl, cold and dehydration and two AS products for PpSR36 after NaCl and cold treatment.