fus() expressions can be used in place of a namespace value within a gene, RNA, or protein abundance function to represent a hybrid gene, or gene product formed from two previously separate genes.
fusion() expressions take the general form:
ns5:v5 is a namespace and value for the 5' fusion partner,
range5' is the sequence coordinates of the 5' partner,
ns3:v3 is a namespace and value for the 3' partner, and
range3' is the sequence coordinates for the 3' partner.
RNA abundance of fusion with known breakpoints
The r. designation in the range fields indicates that the numbering uses the RNA sequence as the reference. RNA sequence numbering starts at the transcription initiation site.